Mono-repo support using Trigger Directories
When first getting started with a Serverless Framework project it is common to have a single serverless.yml
file in a single Github repo. As the project grows it is common to split up the single mono-service into micro-services in individual serverless.yml
files by placing them into different directories in the same repo. In some cases, another directory may exist (e.g. /shared
) which may contain shared libraries used by those services.
As an example, you may end up with a directory structure like this:
/service1
/service2
/shared
In this case, there is a /service1/serverless.yml
and a /service2/serverless.yml
. The services in those two directories may have a dependency on code defined in the /shared
directory. We want to avoid redeploying ALL services every time any of the files change. Instead, we want to run tests and redeploy when the relevant changes are made, in particular:
- If there is a change in
/service1
only deploy/service1/serverless.yml
. - If there is a change in
/service2
only deploy/service2/serverless.yml
. - If there is a change in
/shared
deploy both/service1/serverless.yml
and/service2/serverless.yml
.
In your Serverless CI/CD settings there is a section called “Trigger Directories”. This enables you to limit the changes in a git commit which trigger a deployment by identifying the directories containing the relevant changes. A deployment will occur only if changes in the specified directories are identified. If the changes are in a different directory, the service will not be deployed.
By default the option Always trigger a deployment is checked, which causes ALL changes in the repository to trigger a deployment, which means that all services will get redeployed. Instead we want to uncheck the option and only trigger deployments if changes are detected in the relevant directories.
Once unchecked, the base directory is added by default. This means that only changes in /service1
will cause /service1/serverless.yml
to be deployed, and /service2
for /service2/serverless.yml
respectively. Additionally we also want to deploy both services if changes in /shared
are detected. As such, we’ll add ./shared
as a trigger directory to both services.
With this configuration the changes in /service2
will not cause /service1
to be redeployed, and vice-versa and changes to /shared
will result in both services getting deployed.