# Managing an Application ## Track Application Changes Drycc Workflow tracks all changes to your application. Application changes are the result of either new application code pushed to the platform (via `git push drycc master`), or an update to application configuration (via `drycc config:set KEY=VAL`). Each time a build or config change is made to your application a new [release][] is created. These release numbers increase monotonically. You can see a record of changes to your application using `drycc releases`: ``` $ drycc releases === peachy-waxworks Releases v4 3 minutes ago gabrtv deployed d3ccc05 v3 1 hour 17 minutes ago gabrtv added DATABASE_URL v2 6 hours 2 minutes ago gabrtv deployed 7cb3321 v1 6 hours 2 minutes ago gabrtv deployed drycc/helloworld ``` ## Rollback a Release Drycc Workflow also supports rolling back go previous releases. If buggy code or an errant configuration change is pushed to your application, you may rollback to a previously known, good release. !!! note All rollbacks create a new, numbered release. But will reference the build/code and configuration from the desired rollback point. In this example, the application is currently running release v4. Using `drycc rollback v2` tells Workflow to deploy the build and configuration that was used for release v2. This creates a new release named v5 whose contents are the source and configuration from release v2: ``` $ drycc releases === folksy-offshoot Releases v4 4 minutes ago gabrtv deployed d3ccc05 v3 1 hour 18 minutes ago gabrtv added DATABASE_URL v2 6 hours 2 minutes ago gabrtv deployed 7cb3321 v1 6 hours 3 minutes ago gabrtv deployed drycc/helloworld $ drycc rollback v2 Rolled back to v2 $ drycc releases === folksy-offshoot Releases v5 Just now gabrtv rolled back to v2 v4 4 minutes ago gabrtv deployed d3ccc05 v3 1 hour 18 minutes ago gabrtv added DATABASE_URL v2 6 hours 2 minutes ago gabrtv deployed 7cb3321 v1 6 hours 3 minutes ago gabrtv deployed drycc/helloworld ``` ## Run One-off Administration Tasks Drycc applications [use one-off processes for admin tasks][] like database migrations and other commands that must run against the live application. Use `drycc run` to execute commands on the deployed application. $ drycc run 'ls -l' Running `ls -l`... total 28 -rw-r--r-- 1 root root 553 Dec 2 23:59 LICENSE -rw-r--r-- 1 root root 60 Dec 2 23:59 Procfile -rw-r--r-- 1 root root 33 Dec 2 23:59 README.md -rw-r--r-- 1 root root 1622 Dec 2 23:59 pom.xml drwxr-xr-x 3 root root 4096 Dec 2 23:59 src -rw-r--r-- 1 root root 25 Dec 2 23:59 system.properties drwxr-xr-x 6 root root 4096 Dec 3 00:00 target ## Share an Application Use `drycc perms:create` to allow another Drycc user to collaborate on your application. ``` $ drycc perms:create otheruser Adding otheruser to peachy-waxworks collaborators... done ``` Use `drycc perms` to see who an application is currently shared with, and `drycc perms:remove` to remove a collaborator. !!! note Collaborators can do anything with an application that its owner can do, except delete the application. When working with an application that has been shared with you, clone the original repository and add Drycc' git remote entry before attempting to `git push` any changes to Drycc. ``` $ git clone https://github.com/drycc/example-java-jetty.git Cloning into 'example-java-jetty'... done $ cd example-java-jetty $ git remote add -f drycc ssh://git@local3.dryccapp.com:2222/peachy-waxworks.git Updating drycc From drycc-controller.local:peachy-waxworks * [new branch] master -> drycc/master ``` ## Application Maintenance Maintenance mode for applications is useful to perform certain migrations or upgrades during which we don't want to serve client requests. Drycc Workflow supports maintenance mode for an app during which the access to the app is blocked. Blocking access to the application means all the requests to the app are served with an error code of `503` and a static maintenance page by the router but the app will still be running and one-off commands can still be run. Currently the maintenance page is not configurable and is present as part of the router component. To enable maintenance mode for app, use `drycc maintenance`: $ drycc maintenance:on Enabling maintenance for drafty-zaniness... done This will make the [router][] answer all requests to the application with a 503, although the app is still running. To disable maintenance mode: $ drycc maintenance:off Disabling maintenance for drafty-zaniness... done ## Application Troubleshooting Applications deployed on Drycc Workflow [treat logs as event streams][]. Drycc Workflow aggregates `stdout` and `stderr` from every [Container][] making it easy to troubleshoot problems with your application. Use `drycc logs` to view the log output from your deployed application. $ drycc logs | tail Dec 3 00:30:31 ip-10-250-15-201 peachy-waxworks[web.5]: INFO:oejsh.ContextHandler:started o.e.j.s.ServletContextHandler{/,null} Dec 3 00:30:31 ip-10-250-15-201 peachy-waxworks[web.8]: INFO:oejs.Server:jetty-7.6.0.v20120127 Dec 3 00:30:31 ip-10-250-15-201 peachy-waxworks[web.5]: INFO:oejs.AbstractConnector:Started SelectChannelConnector@0.0.0.0:10005 Dec 3 00:30:31 ip-10-250-15-201 peachy-waxworks[web.6]: INFO:oejsh.ContextHandler:started o.e.j.s.ServletContextHandler{/,null} Dec 3 00:30:31 ip-10-250-15-201 peachy-waxworks[web.7]: INFO:oejsh.ContextHandler:started o.e.j.s.ServletContextHandler{/,null} Dec 3 00:30:31 ip-10-250-15-201 peachy-waxworks[web.6]: INFO:oejs.AbstractConnector:Started SelectChannelConnector@0.0.0.0:10006 Dec 3 00:30:31 ip-10-250-15-201 peachy-waxworks[web.8]: INFO:oejsh.ContextHandler:started o.e.j.s.ServletContextHandler{/,null} Dec 3 00:30:31 ip-10-250-15-201 peachy-waxworks[web.7]: INFO:oejs.AbstractConnector:Started SelectChannelConnector@0.0.0.0:10007 Dec 3 00:30:31 ip-10-250-15-201 peachy-waxworks[web.8]: INFO:oejs.AbstractConnector:Started SelectChannelConnector@0.0.0.0:10008 [application]: ../reference-guide/terms.md#application [container]: ../reference-guide/terms.md#container [release]: ../reference-guide/terms.md#release [store config in environment variables]: http://12factor.net/config [decoupled from the application]: http://12factor.net/backing-services [scale out via the process model]: http://12factor.net/concurrency [treat logs as event streams]: http://12factor.net/logs [use one-off processes for admin tasks]: http://12factor.net/admin-processes [Procfile]: http://ddollar.github.io/foreman/#PROCFILE [router]: ../understanding-workflow/components.md#router