DevLab 1.7 - Links and Exec on Services

If you’ve used DevLab you know a core capability is spinning up services. Services get linked into your container and make them available ephemerally for easy testing of databases, APIs, micro-services, etc.

With version 1.7.0 we’ve extended the capabilities of these services allowing you to link services and exec tasks after the services start.

Linking

The new link config allows you to link multiple services. This is extremely powerful if, for instance, you want to run several micro-services and have them share a datasource.

In the services section of your /devlab.yml file this looks like:

services:
  - someDatabase:
      name: foo
      persist: false
  - someApplication:
      name: bar
      persist: false
      link:
        - foo

Note the link in someApplication (named bar) references the earlier created someDatabase via it’s name (foo). It’s that simple. When someApplication loads up it will have someDatabase available.

Keep in mind the loading of services is done synchronously so you need to have the services in right order so they are available for the other (later) services to reference them.

Exec

As of version 1.6.0 DevLab supports an exec config for any of the services. This is similar in format to the tasks defined at the end of your /devlab.yml except that this will be called immediately after the service container is started.

services:
  - mongo:3.0:
      name: mongodb
      env:
        - DB_ROOT_PASSWORD=foo
      expose:
        - 27017:27017
      persist: false
      exec: |
        echo "Some task"

In the above snippet the exec task would simply run echo "Some task" after the container for Mongo successfully started.

We’re continuing to come up with new ways to improve the capabilites and power of DevLab. Check back on this blog for updates frequently!