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• Log4net 1.2.10 running on .NET 1.1 and 2.0 not compatible

  - by Daniel Williams

  I have old code that uses log4net version 1.2.10 targeted for the .NET 1.1 platform. My current code uses lognet version 1.2.10 targeted for the .NET 2.0 platform When I mix the old and new code all hell breaks loose. Code written today on .NET 4.0 and VS2010 can use the 2.0 log4net dll just fine. but if I put in the 1.1 version, it breaks. Conversely, the old dlls will break if I use the 2.0 log4net dll. I do not want to force my old dlls onto 2.0. Is there a good solution? I guess what bugs me most is that the log4net has the same version number, but I cannot fool my code and dlls into working with a single version.

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• How do I finish this haiku? [closed]

  - by graphicdivine

  Broken old browser, Internet Explorer six, ...

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• ASP.net Associate session with client/request based on ip

  - by ase69s

  In one web page we use a flash upload control but becouse a flash bug in the upload event the session is lost as its posted back with a new session. We have tought of using a table with ip and old session id or a query string with the old session id in order to reassing it in the uploaded event... Knowing the old session id how can i reassign it to the client? (In C#)

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• CSF Unresolved issue

  - by josephmarhee

  I began receiving service failures for CSF/LFD once the limit was reached in iptables preventing the service from working properly. I flushed all iptables rules, and redid by rules using CIDR rather than the individual IPs that were listed and the issue persists. Error: The VPS iptables rule limit (numiptent) is too low (1527/1536) - stopping firewall to prevent iptables blocking all connections, at line 1459 This is after restarting CSF, which gave me: You have an unresolved error when starting csf. You need to restart csf successfully to remove this warning CSF still seems to be trying to enforce rules that no longer exists (lists entire chains upon trying to be restarted,only to fail with that error). Any idea of what's going on?

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• How can I force the server socket to re-accept a request from a client?

  - by Roman

  For those who does not want to read a long question here is a short version: A server has an opened socket for a client. The server gets a request to open a socket from the same client-IP and client-port. I want to fore the server not to refuse such a request but to close the old socket and open a new one. How can I do ti? And here is a long (original) question: I have the following situation. There is an established connection between a server and client. Then an external software (Bonjour) says to my client the it does not see the server in the local network. Well, client does nothing about that because of the following reasons: If Bonjour does not see the server it does not necessarily means that client cannot see the server. Even if the client trusts the Bonjour and close the socket it does not improve the situation ("to have no open socket" is worser that "to have a potentially bad socket"). So, client do nothing if server becomes invisible to Bonjour. But than the server re-appears in the Bonjour and Bonjour notify the client about that. In this situation the following situations are possible: The server reappears on a new IP address. So, the client needs to open a new socket to be able to communicate with the server. The server reappears on the old IP address. In this case we have two subcases: 2.1. The server was restarted (switched off and then switched on). So, it does not remember the old socket (which is still used by the client). So, client needs to close the old socket and open a new one (on the same server-IP address and the same server-port). 2.2. We had a temporal network problem and the server was running the whole time. So, the old socket is still available for the use. In this case the client does not really need to close the old socket and reopen a new one. But to simplify my life I decide to close and reopen the socket on the client side in any case (in spite on the fact that it is not really needed in the last described situation). But I can have problems with that solution. If I close the socket on the client side and than try to reopen a socket from the same client-IP and client-port, server will not accept the call for a new socket. The server will think that such a socket already exists. Can I write the server in such a way, that it does not refuse such calls. For example, if it (the server) sees that a client send a request for a socket from the same client-IP and client-port, it (server) close the available socket, associated with this client-IP and client-port and than it reopens a new socket.

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• ESX Firewall Command Troubles

  - by John

  Hi, I am working on creating some firewall rules to stop some of the SSH brute-force attacks that we have seen recently on our ESX server hosts. I have tried the following rules from the CLI to first block all SSH traffic and then allow the two ranges that I am interested in: esxcfg-firewall --ipruleAdd 0.0.0.0/0,22,tcp,REJECT,"Block_SSH" esxcfg-firewall --ipruleAdd 11.130.0.0/16,22,tcp,ACCEPT,"Allow_PUBLIC_SSH" esxcfg-firewall --ipruleAdd 10.130.0.0/16,22,tcp,ACCEPT,"Allow_PRIVATE_SSH" However, these rules are not working as intended. I know that if you do not enter the block rule first, then the allow rule will not be processed. We are now having the issue where the first entered allow rule is being ignored such that the block rule works and the last entered allow rule works. I was curious if anyone had any ideas on how I could allow a few different ranges of IP's with the esxcfg-firewall --ipruleAdd command? I am at a loss and am having a hard time locating examples or further documentation about this. Thanks in advance for your help with this.

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• Could/Should I use static classes in asp.net/c# for shared data?

  - by death.au

  Here's the situation I have: I'm building an online system to be used by school groups. Only one school can log into the system at any one time, and from that school you'll get about 13 users. They then proceed into a educational application in which they have to co-operate to complete tasks, and from a code point of view, sharing variables all over the place. I was thinking, if I set up a static class with static properties that hold the variables that are required to be shared, this could save me having to store/access the variables in/from a database, as long as the static variables are all properly initialized when the application starts and cleaned up at the end. Of course I would also have to put locks on the get and set methods to make the variables thread safe. Something in the back of my mind is telling me this might be a terrible way of going about things, but I'm not sure exactly why, so if people could give me their thoughts for or against using a static class in this situation, I would be quite appreciative.

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• Detected Dependencies - Where is each dependency coming from?

  - by hawbsl

  I have two detected dependencies with the same name (different paths) showing up in my setup project's detected dependencies. One's the "old" one, at an old path. How can i determine which portion of my primary project is causing the "old" one to show up? I can probably do it by trial and error, but is there a quick/direct way?

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• Apache .shared folder

  - by Kevin

  There are already a bunch of rules in my Apache configuration. What I want to add is the following. There are some shared folders (.shared): /var/www/.shared/ and /var/www/.include/.shared/ and /var/www/.include/(.*)/.shared/. Now when someone visits http://domain.com/test.png it first executes the existing apache rules and will (when the file/folder was not found) look in those .shared folders. So suppose I've got this filesystem: /var/www/.shared/dog.png /var/www/.shared/test.gif and /var/www/domain.com/dog.png. Now when someone visits http://domain.com/test.gif, it must load the test.gif from the .shared folder. Now when someone visits http://domain.com/dog.png it must load the dog.png from the domain.com folder (because the existing apache rules will be executed first).

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• SVN Version Rollback Question

  - by phimuemue

  Hello, I'm using SVN (TortoiseSVN) and often came into the following situation: I wanted to discard any changes since a specific (old) revision and turn all files back to this specific (old) version. Then I wanted to work further as if this specific (old) revision was the newest one, i.e. I wanted to be able to commit the specific old revision as a new revision. I found several solutions for this problem (for example stackoverflow.com/questions/402159/roll-back-or-revert-entire-svn-repository-to-an-older-revision or rustyrazorblade.com/2007/04/how-to-roll-back-commits-to-an-earlier-version-of-a-repository-in-svn/). However, I wonder if there is a simple way to roll back to a specific revision. I thought version control is just good for such things (or am I misunderstanding something?). Is there a simple command/button/etc. that takes an updates my local repository to an old revision and declares it to be the newest one? Since I suppose that there is no "built-in" function to do this, I wanted to know what reason lead the developers to the decision not to integrate this feature. Does anybody know this?

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• Shell script syntax error: unexpected end of line

  - by user1557674

  I wrote a simple shell script to check for the existence of a xml file and if it exists, then rename an old xml file to be backup and then move the new xml file to where the old xml file was stored. #!/bin/sh oldFile="/Documents/sampleFolder/sampleFile.xml" newFile="/Documents/sampleFile.xml" backupFileName="/Documents/sampleFolder/sampleFile2.backup" oldFileLocation="/Documents/sampleFolder" if [ -f "$newFile" ] ; then echo "File found" #Rename old file mv $oldFile $backupFileName #move new file to old file's location mv $newFile $oldFileLocation else echo "File not found, do nothing" fi However, every time I try to run the script, I get 4 command not found messages and a syntax error: unexpected end of file. Any suggestions on why I get these command not found errors or the unexpected end of file? I double checked that I closed all my double quotes, I have code highlight :) EDIT: output from running script: : command not found: : command not found: : command not found1: : command not found6: replaceXML.sh: line 26: syntax error: unexpected end of file

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• Transfer Data between databases with postgres

  - by user227932

  I need to transfer some data from another Database. The old database is called paw1.moviesDB and the new database is paw1. The schema of each table are the following Awards (name of the table)(new DB) Id [PK] Serial Award Nominations (name of the table) (old DB) Id [PK] Serial nominations I want to copy the data from old DB to the new DB.

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• Is the syntax written in descrition is correct for MySQL Triggers? will it work?

  - by Parth

  Is the syntax written in descrition is correct for MySQL Triggers? will it work? CREATE OR REPLACE TRIGGER myTableAuditTrigger 2 AFTER INSERT OR DELETE OR UPDATE ON myTable 3 FOR EACH ROW 4 BEGIN 5 IF INSERTING THEN 6 INSERT INTO myTableAudit (id, Operation, NewName, NewPhone) 7 VALUES (1, 'Insert ', :NEW.Name, :NEW.PhoneNo); 8 ELSIF DELETING THEN 9 INSERT INTO myTableAudit (id, Operation, OldName, OldPhone) 10 VALUES (1, 'Delete ', :OLD.Name, :OLD.PhoneNo); 11 ELSIF UPDATING THEN 12 INSERT INTO myTableAudit (id, Operation, 13 OldName, OldPhone, NewName, NewPhone) 14 VALUES (1, 'Update ', 15 :OLD.Name, :OLD.PhoneNo, :NEW.Name, :NEW.PhoneNo); 16 END IF; 17 END; 18 /

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• Opening a port to make a connection in Windows 7 [closed]

  - by jannes braet

  Possible Duplicate: trouble with opening a port to make a connection I have watched a video on how to open my ports in Windows 7. I followed the example by going to my "firewall" in "advanced settings" and I made new rules in "inbound rules" and in "outbound rules". I chose to allow connections to all ports, but if I try it with canyouseeme, then it says I can't find the configured port. Maybe it is because the site is wrong, but I don't really believe so. Could someone tell me how I open my ports so that I can connect to them and others to connect to them via the internet (if they have my ip-adress of course)?

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• Returning string in java using 3 parameters

  - by user2905118

  Need to write a method describePerson() that takes 3 parameters, a String giving a person’s name, a boolean indicating their gender (true for female, false for male), and an integer giving their age. The method should return a String formatted as in the following examples: Lark is female. She is 2 years old. Or Jay is male. He is 1 year old. I am not sure how to write it correctly (my code): int describePerson(String name, boolean gender, int age) { String words=""; if(gender==true) return (name + "is "+gender+". "+"She is"+age+ "years old.); else return (name + "is "+gender+". "+"She is"+age+ "years old.); } The outcome "year" and "years" is also differs, but i don't know how to make it correct..

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• wordpress not properly functioning anymore after moving it to another domain

  - by Andy

  Hi, I followed the instructions on http://codex.wordpress.org/Moving_WordPress under 'Moving WordPress to a New Server' and 'If You Want Your Old Blog To Still Work' So I made a copy of everything marked is as old, then changed the domain under the WP settings, made a new copy. And now put the first copy back but when I go to the login page I can reach it, but it's without the usual markup as first. It's all skinned out. After I login, worpress uses the new domain instead of the old domain which the old copy of wordpress used!! what went wrong?? thanks.

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• How to configure Unity/Compiz in 12.04 so that Update Manager opens maximized w/screen bigger than 1024×600?

  - by Jani Uusitalo

  In Precise, window auto-maximize is disabled on monitors with a resolution above 1024 × 600 [1]. I have a bigger resolution, but I prefer maximized windows anyway. I want Update Manager to start maximized. What I've tried so far: In Compiz Config Settings Manager, I have Place Windows activated and 'Windows with fixed placement mode' has windows matching the rule "(name=gnome-terminal) | (name=update-manager)" set to 'Maximize'. With this, Gnome Terminal starts maximized, Update Manager does not. In Compiz Config Settings Manager, I have set a Window Rules [2] rule to match "name=update-manager". Irregardless of any rules set or not, activating Window Rules results in not being able to bring out Unity Launcher anymore, Alt+Tab window switching becoming slow or nonfunctional entirely and the screen sporadically freezing completely. Not a viable option apparently. I've installed Maximus [3] and started it. Update Manager ignores it (or vice versa). I've not tried devilspie and would prefer not to. Having to configure something external for this would seem stupidly redundant with (the no-brainer) Maximus and all these Compiz options already available. I just can't seem to make them work. [1] https://bugs.launchpad.net/ayatana-design/+bug/797808 [2] http://askubuntu.com/a/53657/34756 [3] How to configure my system so that all windows start maximized?

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• Windows Azure Evolution &ndash; Preview Developer Portal

  - by Shaun

  With the MEET Windows Azure event on 7th June, there are many new features and updates in windows azure platform. In the coming several posts I will try to cover some of them. And in the first post here I would like to just have a quick walkthrough of the new preview developer portal.   History of the Developer Portal If you have been working with windows azure since 2009 or 2010, you should remember the first version of the developer portal. It was built in HTML with very limited features. I have the impression when I was using is old one. The layout is not that attractive and you have very limited features. On November, 2010 alone with the SDK 1.3 release, the developer portal was getting a big jump. In order to give more usability and features this it turned to be built on Silverlight. Hence it runs like a desktop application with many windows, lists, commands and context menus. From 2010 till now many features were involved into this portal, such as the remote desktop, co-admin, virtual connect, VM role, etc.. And the portal itself became more and more complicated. But it brought some problems by using the Silverlight. The first one is the browser capability. As you know in most mobile and tablet device the browser doesn’t allow the rich content plugin, such as Flash and Silverlight. This means people cannot open and configure their azure services from their iPad, iPhone and Windows Phone, etc., even though what they need may just be restart a hosted service, or view the status of their databases. Another problem is the performance. Silverlight provides rich experience to the users, but also needs more bandwidth. So in this upgrade the preview developer portal will be back to use HTML, with JavaScript, as a mobile friendly, cross browser, interactively web site.   Preview Portal vs. Silverlight Portal Before I started to talk about the new preview portal I’d better highlight that, this preview portal is a PREVIEW version, which means even though you can do almost all features that already in the old one, as long as some cool new features I will mention in the coming several posts, there are something still under developed and migrated. So sometimes you need to switch back to the old one. For example, in preview portal there is no co-admin manage function, no remote desktop function and the SQL database manage function will take you back to the old SQL Azure Manage Portal. But as Microsoft said these missing features will be moved in the preview portal in the couple of next few months. Since the public URL of the developer portal, https://windows.azure.com/, had been changed to point to this preview one, you need to click to preview button on top of the page and click the “Take me to the previous portal” link.   Overview There are four parts in the preview portal. On the top is the header which shows the account you are currently logging in. If you click on the header it will show the top menu of windows azure, where you can navigate to the windows azure home page, the price information page, community and account, etc.. The navigation bar is on the left hand side, with the categories listed below. ALL ITEMS All items in your windows azure account, includes the web sites, services, databases, etc.. WEB SITES The web sites in your windows azure account. It will only show the web sites you have. The linked resources will be shown if you drill down into a web site. VIRTUAL MACHINES The virtual machines that you had been deployed to azure. CLOUD SERVICES All windows azure hosted services in your account. SQL DATABASES All SQL databases (SQL Azure) in your account. STORAGE All windows azure storage services in your account. NETWORKS The virtual network (Windows Azure Connect) you had been created. The available items will be listed in the main part of the page based on which category your currently selected. If there’s no item it will show the link to you to quick create. At the bottom of the page there will be the command and information bar. Based on what is selected and what is performed by the user, it will show the related information and commands. For example, in the image below when I was creating a new web site, the information bar told me that my web site is being provisioned; and there are two commands in the command bar. And once it ready the command bar will show some commands that I can do to my new web site. The “Web Sites” is a new feature introduced alone with this upgrade. It gives us an easier and quicker way to establish a website from the scratch or from some existing library. I will introduce it more details in the coming next post. Also in the command bar you can create a service by clicking the NEW button. It will slide the creation panel up to you.   Where’s My Hosted Services The Windows Azure Hosted Services had been renamed to the Cloud Services. Create a new service would be very easy. Just click the NEW button at the bottom of the page, and select the CLOUD SERVICE and QIUICK CREATE. This will create a blank hosted service without deployment and certificate. It just needs you to specify the service URL and the affinity/region. Then the service will be shown in the list. If you clicked the item all information will be shown in the main part. Since there’s no package deployed to this service so currently we cannot see any information about it. But we can upload the package by using the command at the bottom. And as you can see, we could manage the configuration, instances, certificates and we can scale up and down (change the VM size), in and out (increase and decrease the instance count) to our service. Assuming I had created an ASP.NET MVC 3 web role project in Visual Studio and completed the package. Then I can click the UPLOAD button in this page to deploy my package. In the popping up window I just specify my deployment name, package file and configure file. Also I can check the box below so that it will NOT warn me if only one instance of this deployment. Once we clicked the OK button our package will be uploaded and provisioned by the platform. After a while we can see the service was ready from the information bar. We can have the basic information about this service and deployment if we to the dashboard page. For example the usage overview diagram, status, URL, public IP address, etc.. In the configure page we can view and change the CSCFG content such as the monitor setting, connection strings, OS family. In scale page we can increase and decrease the count of the instances. And in the instances page we can view all instances status. And, if your services is using some SQL databases and storages they will be shown as the linked resources under the linked resources page. And you can manage the certificates of this service as well under the certificates page.   How About My Storage Services The storage service can be managed by clicking into the STORAGES link in the navigation bar. And we can create a new storage service from the NEW button. After specify the storage name and region it will be previsioned by the platform. If you want to copy or manage the storage key you can just click the Manage Keys button at the bottom, which is very easy. What I want to highlight here is that, you can monitor your storage service by enabling the monitor configuration. Click the storage item in the list and navigate to the configure page. As you can see in the page you can enable the monitoring for blob, table and queue. And you can also enable the logging when any requests come to the storage. But as the tooltip shown in the page, enabling the monitoring and logging will increase the usage of the storage, which means increase the bill of them. So make sure you enable them properly.   And My SQL Databases (SQL Azure) The last thing I want to quick introduce is the SQL databases, which was formally named SQL Azure. You can create a new SQL Database Server and a new database by clicking the ADD button under the SQL Database navigation item. In the popping up windows just specify the database name, the edition, size, collation and the server. You can select an existing SQL Database Server if you have, or cerate a new one. If you selected to create a new server, there will be another step you need to do, which is specify the server login, password and the region. Once it ready you can mange your databases as well as the servers in the portal. In a particular server you can update the firewall settings in its Configure page. So, What Else There are some other area on the preview portal I didn’t cover, such as the virtual machines, virtual network and web sites. Regarding the virtual machines and web sites I will talk about them in the future separated post. Regarding the virtual network, it the Windows Azure Connect we are familiar with. But as I mention in the beginning of this post, the preview portal is still under developed. Some features are not available here. For example, you cannot manage the co-admin of your subscriptions, you cannot open the remote desktop on your hosted services, and you cannot navigate to the Windows Azure Service Bus, Access Control and Caching, which formally named Windows Azure AppFabric directly. In these cases you need to navigate back to the old portal. So in the coming several months we might need to use both these two sites.   Summary In this post I quick introduced the new windows azure developer portal. Since it had been rearranged and renamed I demonstrated some features that existing in the old portal, such as how to create and deploy a hosted service, how to provision a storage service and SQL database. All features in the old portal had been, is being and will be migrated into this new portal, but some of them were in a different category and page we need to figure out.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• Oracle Technology Network Virtual Developer Day: Service Oriented Architecture (SOA)

  - by programmarketingOTN

  Register now! Oracle Technology Network Virtual Developer Day: Service Oriented Architecture (SOA) - Discover the Power of Oracle SOA Suite 11gTuesday July 12, 2011 - ?9:00 a.m. PT – 1:30 p.m. PT / 12 Noon EDT - 4:30 p.m. EDTOTN is proud to host another Virtual Developer Day, this time focusing on SOA (click here to check out on-demand version of Rich Enterprise Applications and WebLogic)  Save yourself/company some money and join us online for this hands-on virtual workshop. Through developer-focused product presentations and demonstrations delivered by Oracle product and technology experts, there is no faster or more efficient way to jumpstart your Oracle SOA suite learning.Over the course of the Virtual Developer Day, you will learn how an SOA approach can be implemented, whether starting fresh with new services or reusing existing services. Using Oracle SOA Suite 11g components, you will explore, modify, execute, and monitor an SOA composite application. Topics include SCA, BPEL process execution, adapters, business rules and more.Java and WebLogic experience not required for the presentations or demonstrations but it is a plus for the hands-on lab.Come to this event if you are    •    Exploring ways to deliver services faster    •    Integrating packaged and/or legacy applications    •    Developing service orchestration    •    Planning or starting new development projectsRegister online now for this FREE event.AGENDA - Tuesday July 12, 2011?9:00 a.m. PT – 1:30 p.m. PT / 12 Noon EDT - 4:30 p.m. PT EDT  Time  Title  9:00 AM Keynote  9:15 AM Presentation 1 Service Oriented Architecture (SOA) Overview  9:45 AM Demonstration 1 Mediator and Adapters  10:15 AM Presentation 2 BPEL Service Orchestration and Business Rules  10:45 AM Demonstration 2 BPEL Service Orchestration  11:15 AM Demonstration 3 Oracle Business Rules  11:45 AM Hands-on Lab time  1:30 PM Close Register online now for this FREE event.

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• Juju Zookeeper & Provisioning Agent Not Deployed

  - by Keith Tobin

  I am using juju with the openstack provider, i expected that when i bootstrap that zookeeper and provisioning agent would get deployed on the bootstrap vm in openstack. This dose not seem to be the case. the bootstrap vm gets deployed but it seems that nothing gets deployed to the VM. See logs below, I may be missing something, also how is it possible to log on the bootstrap vm. Could I manual deploy, if so what do I need to do. Juju Bootstrap commend root@cinder01:/home/cinder# juju -v bootstrap 2012-10-12 03:21:20,976 DEBUG Initializing juju bootstrap runtime 2012-10-12 03:21:20,982 WARNING Verification of xxxxS certificates is disabled for this environment. Set 'ssl-hostname-verification' to ensure secure communication. 2012-10-12 03:21:20,982 DEBUG openstack: using auth-mode 'userpass' with xxxx:xxxxxx.10:35357/v2.0/ 2012-10-12 03:21:21,064 DEBUG openstack: authenticated til u'2012-10-13T08:21:13Z' 2012-10-12 03:21:21,064 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors' 2012-10-12 03:21:21,091 DEBUG openstack: 200 '{"flavors": [{"id": "3", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/3", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/3", "rel": "bookmark"}], "name": "m1.medium"}, {"id": "4", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/4", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/4", "rel": "bookmark"}], "name": "m1.large"}, {"id": "1", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "bookmark"}], "name": "m1.tiny"}, {"id": "5", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/5", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/5", "rel": "bookmark"}], "name": "m1.xlarge"}, {"id": "2", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/2", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/2", "rel": "bookmark"}], "name": "m1.small"}]}' 2012-10-12 03:21:21,091 INFO Bootstrapping environment 'openstack' (origin: ppa type: openstack)... 2012-10-12 03:21:21,091 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state 2012-10-12 03:21:21,092 DEBUG openstack: GET 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state' 2012-10-12 03:21:21,165 DEBUG openstack: 200 '{}\n' 2012-10-12 03:21:21,165 DEBUG Verifying writable storage 2012-10-12 03:21:21,165 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/bootstrap-verify 2012-10-12 03:21:21,166 DEBUG openstack: PUT 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/bootstrap-verify' 2012-10-12 03:21:21,251 DEBUG openstack: 201 '201 Created\n\n\n\n ' 2012-10-12 03:21:21,251 DEBUG Launching juju bootstrap instance. 2012-10-12 03:21:21,271 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/juju_master_id 2012-10-12 03:21:21,273 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-groups 2012-10-12 03:21:21,273 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-groups' 2012-10-12 03:21:21,321 DEBUG openstack: 200 '{"security_groups": [{"rules": [{"from_port": -1, "group": {}, "ip_protocol": "icmp", "to_port": -1, "parent_group_id": 1, "ip_range": {"cidr": "0.0.0.0/0"}, "id": 7}, {"from_port": 22, "group": {}, "ip_protocol": "tcp", "to_port": 22, "parent_group_id": 1, "ip_range": {"cidr": "0.0.0.0/0"}, "id": 38}], "tenant_id": "d5f52673953f49e595279e89ddde979d", "id": 1, "name": "default", "description": "default"}]}' 2012-10-12 03:21:21,322 DEBUG Creating juju security group juju-openstack 2012-10-12 03:21:21,322 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-groups' 2012-10-12 03:21:21,401 DEBUG openstack: 200 '{"security_group": {"rules": [], "tenant_id": "d5f52673953f49e595279e89ddde979d", "id": 48, "name": "juju-openstack", "description": "juju group for openstack"}}' 2012-10-12 03:21:21,401 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-group-rules' 2012-10-12 03:21:21,504 DEBUG openstack: 200 '{"security_group_rule": {"from_port": 22, "group": {}, "ip_protocol": "tcp", "to_port": 22, "parent_group_id": 48, "ip_range": {"cidr": "0.0.0.0/0"}, "id": 54}}' 2012-10-12 03:21:21,504 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-group-rules' 2012-10-12 03:21:21,647 DEBUG openstack: 200 '{"security_group_rule": {"from_port": 1, "group": {"tenant_id": "d5f52673953f49e595279e89ddde979d", "name": "juju-openstack"}, "ip_protocol": "tcp", "to_port": 65535, "parent_group_id": 48, "ip_range": {}, "id": 55}}' 2012-10-12 03:21:21,647 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-group-rules' 2012-10-12 03:21:21,791 DEBUG openstack: 200 '{"security_group_rule": {"from_port": 1, "group": {"tenant_id": "d5f52673953f49e595279e89ddde979d", "name": "juju-openstack"}, "ip_protocol": "udp", "to_port": 65535, "parent_group_id": 48, "ip_range": {}, "id": 56}}' 2012-10-12 03:21:21,792 DEBUG Creating machine security group juju-openstack-0 2012-10-12 03:21:21,792 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-security-groups' 2012-10-12 03:21:21,871 DEBUG openstack: 200 '{"security_group": {"rules": [], "tenant_id": "d5f52673953f49e595279e89ddde979d", "id": 49, "name": "juju-openstack-0", "description": "juju group for openstack machine 0"}}' 2012-10-12 03:21:21,871 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/detail 2012-10-12 03:21:21,871 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/detail' 2012-10-12 03:21:21,906 DEBUG openstack: 200 '{"flavors": [{"vcpus": 2, "disk": 10, "name": "m1.medium", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/3", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/3", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 40, "ram": 4096, "id": "3", "swap": ""}, {"vcpus": 4, "disk": 10, "name": "m1.large", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/4", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/4", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 80, "ram": 8192, "id": "4", "swap": ""}, {"vcpus": 1, "disk": 0, "name": "m1.tiny", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 0, "ram": 512, "id": "1", "swap": ""}, {"vcpus": 8, "disk": 10, "name": "m1.xlarge", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/5", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/5", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 160, "ram": 16384, "id": "5", "swap": ""}, {"vcpus": 1, "disk": 10, "name": "m1.small", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/flavors/2", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/2", "rel": "bookmark"}], "rxtx_factor": 1.0, "OS-FLV-EXT-DATA:ephemeral": 20, "ram": 2048, "id": "2", "swap": ""}]}' 2012-10-12 03:21:21,907 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers 2012-10-12 03:21:21,907 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers' 2012-10-12 03:21:22,284 DEBUG openstack: 202 '{"server": {"OS-DCF:diskConfig": "MANUAL", "id": "a598b402-8678-4447-baeb-59255409a023", "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "bookmark"}], "adminPass": "SuFp48cZzdo4"}}' 2012-10-12 03:21:22,284 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/juju_master_id 2012-10-12 03:21:22,285 DEBUG openstack: PUT 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/juju_master_id' 2012-10-12 03:21:22,375 DEBUG openstack: 201 '201 Created\n\n\n\n ' 2012-10-12 03:21:27,379 DEBUG Waited for 5 seconds for networking on server u'a598b402-8678-4447-baeb-59255409a023' 2012-10-12 03:21:27,380 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023 2012-10-12 03:21:27,380 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023' 2012-10-12 03:21:27,556 DEBUG openstack: 200 '{"server": {"OS-EXT-STS:task_state": "networking", "addresses": {"private": [{"version": 4, "addr": "10.0.0.8"}]}, "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "bookmark"}], "image": {"id": "5bf60467-0136-4471-9818-e13ade75a0a1", "links": [{"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/images/5bf60467-0136-4471-9818-e13ade75a0a1", "rel": "bookmark"}]}, "OS-EXT-STS:vm_state": "building", "OS-EXT-SRV-ATTR:instance_name": "instance-00000060", "flavor": {"id": "1", "links": [{"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "bookmark"}]}, "id": "a598b402-8678-4447-baeb-59255409a023", "user_id": "01610f73d0fb4922aefff09f2627e50c", "OS-DCF:diskConfig": "MANUAL", "accessIPv4": "", "accessIPv6": "", "progress": 0, "OS-EXT-STS:power_state": 0, "config_drive": "", "status": "BUILD", "updated": "2012-10-12T08:21:23Z", "hostId": "1cdb25708fb8e464d83a69fe4a024dcd5a80baf24a82ec28f9d9f866", "OS-EXT-SRV-ATTR:host": "nova01", "key_name": "", "OS-EXT-SRV-ATTR:hypervisor_hostname": null, "name": "juju openstack instance 0", "created": "2012-10-12T08:21:22Z", "tenant_id": "d5f52673953f49e595279e89ddde979d", "metadata": {}}}' 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 2012-10-12 03:21:27,557 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-floating-ips 2012-10-12 03:21:27,557 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/os-floating-ips' 2012-10-12 03:21:27,815 DEBUG openstack: 200 '{"floating_ips": [{"instance_id": "a0e0df11-91c0-4801-95b3-62d910d729e9", "ip": "xxxx.35", "fixed_ip": "10.0.0.5", "id": 447, "pool": "nova"}, {"instance_id": "b84f1a42-7192-415e-8650-ebb1aa56e97f", "ip": "xxxx.36", "fixed_ip": "10.0.0.6", "id": 448, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.37", "fixed_ip": null, "id": 449, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.38", "fixed_ip": null, "id": 450, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.39", "fixed_ip": null, "id": 451, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.40", "fixed_ip": null, "id": 452, "pool": "nova"}, {"instance_id": null, "ip": "xxxx.41", "fixed_ip": null, "id": 453, "pool": "nova"}]}' 2012-10-12 03:21:27,815 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023/action 2012-10-12 03:21:27,816 DEBUG openstack: POST 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023/action' 2012-10-12 03:21:28,356 DEBUG openstack: 202 '' 2012-10-12 03:21:28,356 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state 2012-10-12 03:21:28,357 DEBUG openstack: PUT 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state' 2012-10-12 03:21:28,446 DEBUG openstack: 201 '201 Created\n\n\n\n ' 2012-10-12 03:21:28,446 INFO 'bootstrap' command finished successfully Juju Status Command root@cinder01:/home/cinder# juju -v status 2012-10-12 03:23:28,314 DEBUG Initializing juju status runtime 2012-10-12 03:23:28,320 WARNING Verification of xxxxS certificates is disabled for this environment. Set 'ssl-hostname-verification' to ensure secure communication. 2012-10-12 03:23:28,320 DEBUG openstack: using auth-mode 'userpass' with xxxx:xxxxxx.10:35357/v2.0/ 2012-10-12 03:23:28,320 INFO Connecting to environment... 2012-10-12 03:23:28,403 DEBUG openstack: authenticated til u'2012-10-13T08:23:20Z' 2012-10-12 03:23:28,403 DEBUG access object-store @ xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state 2012-10-12 03:23:28,403 DEBUG openstack: GET 'xxxx:xx10.49.113.11:8080/v1/AUTH_d5f52673953f49e595279e89ddde979d/juju-hpc-az1-cb/provider-state' 2012-10-12 03:23:35,480 DEBUG openstack: 200 'zookeeper-instances: [a598b402-8678-4447-baeb-59255409a023]\n' 2012-10-12 03:23:35,480 DEBUG access compute @ xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023 2012-10-12 03:23:35,480 DEBUG openstack: GET 'xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023' 2012-10-12 03:23:35,662 DEBUG openstack: 200 '{"server": {"OS-EXT-STS:task_state": null, "addresses": {"private": [{"version": 4, "addr": "10.0.0.8"}, {"version": 4, "addr": "xxxx.37"}]}, "links": [{"href": "xxxx:xxxxxx.15:8774/v1.1/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "self"}, {"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/servers/a598b402-8678-4447-baeb-59255409a023", "rel": "bookmark"}], "image": {"id": "5bf60467-0136-4471-9818-e13ade75a0a1", "links": [{"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/images/5bf60467-0136-4471-9818-e13ade75a0a1", "rel": "bookmark"}]}, "OS-EXT-STS:vm_state": "active", "OS-EXT-SRV-ATTR:instance_name": "instance-00000060", "flavor": {"id": "1", "links": [{"href": "xxxx:xxxxxx.15:8774/d5f52673953f49e595279e89ddde979d/flavors/1", "rel": "bookmark"}]}, "id": "a598b402-8678-4447-baeb-59255409a023", "user_id": "01610f73d0fb4922aefff09f2627e50c", "OS-DCF:diskConfig": "MANUAL", "accessIPv4": "", "accessIPv6": "", "progress": 0, "OS-EXT-STS:power_state": 1, "config_drive": "", "status": "ACTIVE", "updated": "2012-10-12T08:21:40Z", "hostId": "1cdb25708fb8e464d83a69fe4a024dcd5a80baf24a82ec28f9d9f866", "OS-EXT-SRV-ATTR:host": "nova01", "key_name": "", "OS-EXT-SRV-ATTR:hypervisor_hostname": null, "name": "juju openstack instance 0", "created": "2012-10-12T08:21:22Z", "tenant_id": "d5f52673953f49e595279e89ddde979d", "metadata": {}}}' 2012-10-12 03:23:35,663 DEBUG Connecting to environment using xxxx.37... 2012-10-12 03:23:35,663 DEBUG Spawning SSH process with remote_user="ubuntu" remote_host="xxxx.37" remote_port="2181" local_port="45859". 2012-10-12 03:23:36,173:4355(0x7fd581973700):ZOO_INFO@log_env@658: Client environment:zookeeper.version=zookeeper C client 3.3.5 2012-10-12 03:23:36,173:4355(0x7fd581973700):ZOO_INFO@log_env@662: Client environment:host.name=cinder01 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@669: Client environment:os.name=Linux 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@670: Client environment:os.arch=3.2.0-23-generic 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@671: Client environment:os.version=#36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@679: Client environment:user.name=cinder 2012-10-12 03:23:36,174:4355(0x7fd581973700):ZOO_INFO@log_env@687: Client environment:user.home=/root 2012-10-12 03:23:36,175:4355(0x7fd581973700):ZOO_INFO@log_env@699: Client environment:user.dir=/home/cinder 2012-10-12 03:23:36,175:4355(0x7fd581973700):ZOO_INFO@zookeeper_init@727: Initiating client connection, host=localhost:45859 sessionTimeout=10000 watcher=0x7fd57f9146b0 sessionId=0 sessionPasswd= context=0x2c1dab0 flags=0 2012-10-12 03:23:36,175:4355(0x7fd577fff700):ZOO_ERROR@handle_socket_error_msg@1579: Socket [127.0.0.1:45859] zk retcode=-4, errno=111(Connection refused): server refused to accept the client 2012-10-12 03:23:39,512:4355(0x7fd577fff700):ZOO_ERROR@handle_socket_error_msg@1579: Socket [127.0.0.1:45859] zk retcode=-4, errno=111(Connection refused): server refused to accept the client 2012-10-12 03:23:42,848:4355(0x7fd577fff700):ZOO_ERROR@handle_socket_error_msg@1579: Socket [127.0.0.1:45859] zk retcode=-4, errno=111(Connection refused): server refused to accept the client ^Croot@cinder01:/home/cinder#

  Read the article

• Evil DRY

  - by StefanSteinegger

  DRY (Don't Repeat Yourself) is a basic software design and coding principle. But there is just no silver bullet. While DRY should increase maintainability by avoiding common design mistakes, it could lead to huge maintenance problems when misunderstood. The root of the problem is most probably that many developers believe that DRY means that any piece of code that is written more then once should be made reusable. But the principle is stated as "Every piece of knowledge must have a single, unambiguous, authoritative representation within a system." So the important thing here is "knowledge". Nobody ever said "every piece of code". I try to give some examples of misusing the DRY principle. Code Repetitions by Coincidence There is code that is repeated by pure coincidence. It is not the same code because it is based on the same piece of knowledge, it is just the same by coincidence. It's hard to give an example of such a case. Just think about some lines of code the developer thinks "I already wrote something similar". Then he takes the original code, puts it into a public method, even worse into a base class where none had been there before, puts some weird arguments and some if or switch statements into it to support all special cases and calls this "increasing maintainability based on the DRY principle". The resulting "reusable method" is usually something the developer not even can give a meaningful name, because its contents isn't anything specific, it is just a bunch of code. For the same reason, nobody will really understand this piece of code. Typically this method only makes sense to call after some other method had been called. All the symptoms of really bad design is evident. Fact is, writing this kind of "reusable methods" is worse then copy pasting! Believe me. What will happen when you change this weird piece of code? You can't say what'll happen, because you can't understand what the code is actually doing. So better don't touch it anymore. Maintainability just died. Of course this problem is with any badly designed code. But because the developer tried to make this method as reusable as possible, large parts of the system get dependent on it. Completely independent parts get tightly coupled by this common piece of code. Changing on the single common place will have effects anywhere in the system, a typical symptom of too tight coupling. Without trying to dogmatically (and wrongly) apply the DRY principle, you just had a system with a weak design. Now you get a system which just can't be maintained anymore. So what can you do against it? When making code reusable, always identify the generally reusable parts of it. Find the reason why the code is repeated, find the common "piece of knowledge". If you have to search too far, it's probably not really there. Explain it to a colleague, if you can't explain or the explanation is to complicated, it's probably not worth to reuse. If you identify the piece of knowledge, don't forget to carefully find the place where it should be implemented. Reusing code is never worth giving up a clean design. Methods always need to do something specific. If you can't give it a simple and explanatory name, you did probably something weird. If you can't find the common piece of knowledge, try to make the code simpler. For instance, if you have some complicated string or collection operations within this code, write some general-purpose operations into a helper class. If your code gets simple enough, its not so bad if it can't be reused. If you are not able to find anything simple and reasonable, copy paste it. Put a comment into the code to reference the other copies. You may find a solution later. Requirements Repetitions by Coincidence Let's assume that you need to implement complex tax calculations for many countries. It's possible that some countries have very similar tax rules. These rules are still completely independent from each other, since every country can change it of its own. (Assumed that this similarity is actually by coincidence and not by political membership. There might be basic rules applying to all European countries. etc.) Let's assume that there are similarities between an Asian country and an African country. Moving the common part to a central place will cause problems. What happens if one of the countries changes its rules? Or - more likely - what happens if users of one country complain about an error in the calculation? If there is shared code, it is very risky to change it, even for a bugfix. It is hard to find requirements to be repeated by coincidence. Then there is not much you can do against the repetition of the code. What you really should consider is to make coding of the rules as simple as possible. So this independent knowledge "Tax Rules in Timbuktu" or wherever should be as pure as possible, without much overhead and stuff that does not belong to it. So you can write every independent requirement short and clean. DRYing try-catch and using Blocks This is a technical issue. Blocks like try-catch or using (e.g. in C#) are very hard to DRY. Imagine a complex exception handling, including several catch blocks. When the contents of the try block as well as the contents of the individual catch block are trivial, but the whole structure is repeated on many places in the code, there is almost no reasonable way to DRY it. try { // trivial code here using (Thingy thing = new thingy) { //trivial, but always different line of code } } catch(FooException foo) { // trivial foo handling } catch (BarException bar) { // trivial bar handling } catch { // trivial common handling } finally { // trivial finally block } The key here is that every block is trivial, so there is nothing to just move into a separate method. The only part that differs from case to case is the line of code in the body of the using block (or any other block). The situation is especially interesting if the many occurrences of this structure are completely independent: they appear in classes with no common base class, they don't aggregate each other and so on. Let's assume that this is a common pattern in service methods within the whole system. Examples of Evil DRYing in this situation: Put a if or switch statement into the method to choose the line of code to execute. There are several reasons why this is not a good idea: The close coupling of the formerly independent implementation is the strongest. Also the readability of the code and the use of a parameter to control the logic. Put everything into a method which takes a delegate as argument to call. The caller just passes his "specific line of code" to this method. The code will be very unreadable. The same maintainability problems apply as for any "Code Repetition by Coincidence" situations. Enforce a base class to all the classes where this pattern appears and use the template method pattern. It's the same readability and maintainability problem as above, but additionally complex and tightly coupled because of the base class. I would call this "Inheritance by Coincidence" which will not lead to great software design. What can you do against it: Ideally, the individual line of code is a call to a class or interface, which could be made individual by inheritance. If this would be the case, it wouldn't be a problem at all. I assume that it is no such a trivial case. Consider to refactor the error concept to make error handling easier. The last but not worst option is to keep the replications. Some pattern of code must be maintained in consistency, there is nothing we can do against it. And no reason to make it unreadable. Conclusion The DRY-principle is an important and basic principle every software developer should master. The key is to identify the "pieces of knowledge". There is code which can't be reused easily because of technical reasons. This requires quite a bit flexibility and creativity to make code simple and maintainable. It's not the problem of the principle, it is the problem of blindly applying a principle without understanding the problem it should solve. The result is mostly much worse then ignoring the principle.

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• Developing a Configurable Pricing Program

  - by Ben DeMott

  The organization I work at has some interesting requirements when it comes to pricing for online commerce. Currently the developers write different 'pricing rules' and those rules can be applied to our items based on attributes of the items. For Example: INPUTS: [cost, sug_retail, discontinued, warehouse_qty, orderable_qty, brand, type, days_available, shipping_rate, weight, map_protected, map_discount] MATCH: brand=x, warehouse_qty 1, discontinued=True, map_protected=False SET: retail_price = (sug_retail * 0.95), offer_price1 = (cost * 1.25 + shipping_rate) I am looking to allow the merchandising team to have more control over the pricing and formulas - they are afterall technical enough to write excel formulas. I've been looking at writing a desktop application that uses something like numexpr http://code.google.com/p/numexpr/ or http://sympy.org/en/index.html to allow non-programmers to integrate their own logic into our pricing backend. We have multiple price-tiers we have to set, for multiple markets, so an elegant solution is needed. It's getting frustrating for the dev team to continually tweak/manage all of the pricing rules (we sell over 200 brands in 3 markets). My question is; does this seem like a decent approach? Can you think of a better way to parse string-mathematical-grammer? Can you think of a different way for users to provide formula's to integrate into a automated pricing system? Does anyone know of any examples of existing applications that do this? Excel, and Access are out of the question - the volume of data we manipulate has already proven the need to automate it - now we just need some visibility into that automation.

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• NetworkManager broken after upgrade to Kubuntu Saucy

  - by queueoverflow

  I had Kubuntu 13.04 on my ThinkPad X220, and I upgraded to 13.10 and I am not able to connect to a wired or wireless connection. The new network tray icon does not show any entries at all. In the menu of the tray icon, there is an error saying: Require NetworkManager 0.9.8, found . I then tried the following: nmcli con ** (process:3695): WARNING **: Could not initialize NMClient /org/freedesktop/NetworkManager: Rejected send message, 3 matched rules; type="method_call", sender=":1.64" (uid=1000 pid=3695 comm="nmcli con ") interface="org.freedesktop.DBus.Properties" member="GetAll" error name="(unset)" requested_reply="0" destination="org.freedesktop.NetworkManager" (uid=0 pid=1116 comm="NetworkManager ") Error: nmcli (0.9.8.0) and NetworkManager (unknown) versions don't match. Force execution using --nocheck, but the results are unpredictable. nmcli dev ** (process:3700): WARNING **: Could not initialize NMClient /org/freedesktop/NetworkManager: Rejected send message, 3 matched rules; type="method_call", sender=":1.65" (uid=1000 pid=3700 comm="nmcli dev ") interface="org.freedesktop.DBus.Properties" member="GetAll" error name="(unset)" requested_reply="0" destination="org.freedesktop.NetworkManager" (uid=0 pid=1116 comm="NetworkManager ") Error: nmcli (0.9.8.0) and NetworkManager (unknown) versions don't match. Force execution using --nocheck, but the results are unpredictable. nm-tool ** (process:3705): WARNING **: Could not initialize NMClient /org/freedesktop/NetworkManager: Rejected send message, 3 matched rules; type="method_call", sender=":1.66" (uid=1000 pid=3705 comm="nm-tool ") interface="org.freedesktop.DBus.Properties" member="GetAll" error name="(unset)" requested_reply="0" destination="org.freedesktop.NetworkManager" (uid=0 pid=1116 comm="NetworkManager ") NetworkManager Tool State: unknown ** (process:3705): WARNING **: error: could not connect to NetworkManager Running those as root works, however. I was also able to run nmcli con up id DHCP which got my DHCP connection working and giving me internet access. That did not work using a Wifi connection though, and I do need those. How can I get networking back to work without a reinstall?

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• Error when running debuild on package source

  - by Chris Wilson

  I'm attempting to build the squeak-vm source but am getting an error every time I do so. The output is: dpkg-buildpackage -rfakeroot -D -us -uc dpkg-buildpackage: export CFLAGS from dpkg-buildflags (origin: vendor): -g -O2 dpkg-buildpackage: export CPPFLAGS from dpkg-buildflags (origin: vendor): dpkg-buildpackage: export CXXFLAGS from dpkg-buildflags (origin: vendor): -g -O2 dpkg-buildpackage: export FFLAGS from dpkg-buildflags (origin: vendor): -g -O2 dpkg-buildpackage: export LDFLAGS from dpkg-buildflags (origin: vendor): -Wl,-Bsymbolic-functions dpkg-buildpackage: source package squeak-vm dpkg-buildpackage: source version 1:4.0.3.2202-2 dpkg-buildpackage: source changed by José L. Redrejo Rodríguez <[email protected]> dpkg-source --before-build squeak-vm-4.0.3.2202 dpkg-buildpackage: host architecture i386 fakeroot debian/rules clean dh_testdir dh_testroot rm -f build-stamp configure-stamp rm -f unix/cmake/config.sub unix/cmake/config.guess /usr/bin/make -f debian/rules unpatch make[1]: Entering directory `/home/notgary/Projects/squeak/squeak-vm-4.0.3.2202' QUILT_PATCHES=debian/patches \ quilt --quiltrc /dev/null pop -a -R || test $? = 2 Patch linex.patch does not remove cleanly (refresh it or enforce with -f) make[1]: *** [unpatch] Error 1 make[1]: Leaving directory `/home/notgary/Projects/squeak/squeak-vm-4.0.3.2202' make: *** [clean] Error 2 dpkg-buildpackage: error: fakeroot debian/rules clean gave error exit status 2 debuild: fatal error at line 1337: dpkg-buildpackage -rfakeroot -D -us -uc failed

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• How to balance a non-symmetric "extension" based game?

  - by Klaim

  Most strategy games have fixed units and possible behaviours. However, think of a game like Magic The Gathering : each card is a set of rules. Regularly, new sets of card types are created. I remember that the firsts editions of the game have been said to be prohibited in official tournaments because the cards were often too powerful. Later extensions of the game provided more subtle effects/rules in cards and they managed to balance the game apparently effectively, even if there is thousands of different cards possible. I'm working on a strategy game that is a bit in the same position : every units are provided by extensions and the game is thought to be extended for some years, at least. The effects variety of the units are very large even with some basic design limitations set to be sure it's manageable. Each player choose a set of units to play with (defining their global strategy) before playing (like chooseing a themed deck of Magic cards). As it's a strategy game (you can think of Magic as a strategy game too in some POV), it's essentially skirmish based so the game have to be fair, even if the players don't choose the same units before starting to play. So, how do you proceed to balance this type of non-symmetric (strategy) game when you know it will always be extended? For the moment, I'm trying to apply those rules but I'm not sure it's right because I don't have enough design experience to know : each unit would provide one unique effect; each unit should have an opposite unit that have an opposite effect that would cancel each others; some limitations based on the gameplay; try to get a lot of beta tests before each extension release? Looks like I'm in the most complex case?

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