Agola secrets and variables are a powerful way to provide secret data to a run (that cannot be stored inside the run definition or it'll leak important secrets)
They are designed to achieve multiple goals:
- Ability to execute a run on different environments reusing the same run definition (avoiding as much as possible creating conditional tasks based on the environment). The idea is that users could "test" a run on a testing environment when opening a PR or committing to a development branch and then use the same run definition when merging the PR/branch or creating a tag to deploy on the production environemt. This is achieved by the variable values conditions: a variable will have a different value based on the first matching condition (branch, tag, ref).
- Ability to inherit secret/variables on multiple project. I.E. define the secrets/variable on a project group and have them inherited by all the child projects/projectgroups. In this way user don't have to redefine the same secret/variable multiple times on every project and manage to keep them updated when something changes.
Every project group or project can have some secrets assigned. These secrets can be:
- local secrets
- remote secrets: secrets provided by a remote secret manager (like hashicorp vault)
Secrets are "inherited" by child projectgroups/projects
Currently only local secrets are implemented (see the related enhancement tracking issue)
Every project group or project can have some variables defined. Variables can have multiple values and the final value assigned to a run depends on the matched value condition. The variable value references a secret. The first secret with the referenced name starting from the current project and walking up until the root project group will be used. Currently if no secret is found the variable values will be empty.
Like secrets also variables are "inherited" by child projectgroups/projects
Suppose we have a project group called "product01" and two sub projects "service01" and "service02". These projects will have a run definition that, after successful build and tests will build a docker image and push it to a docker registry and then deploy the service to a kubernetes cluster.
We'll use a git based workflow where the master branch is the primary branch, users will create PRs (tests and code review) and then merge PRs on the master branch. When master is ready for a release a tag will be pushed.
PRs will use their own test environments, master will use it's own staging environment and tags will use the production environment.
We could create 3 different secrets with all the related key/value pairs (docker registry auth, k8s cluster auth etc...) for testing/staging/production
We'll then define a variable containing the docker credential with some condition that will choose the right variable. Example using the cli.
Create the secrets
dockerpassword: secretdockerpassword kubecfg: kubecfgbase64
agola projectgroup secret create --projectgroup org/org01/product01 --name secret-testing -f secret-testing.yml
Then we'll do the same for the staging and production secrets.
Create the variable
- secret_name: secret-testing secret_var: dockerpassword when: ref: '#/refs/pull/.*#' - secret_name: secret-staging secret_var: dockerpassword when: branch: master - secret_name: secret-production secret_var: dockerpassword when: tag: '#v1\..*'
agola projectgroup variable create --projectgroup org/org01/product01 --name dockerpassword -f dockerpassword.yml
Then we'll do the same for the other variables (i.e. kubecfg)
Our run definition can be the same. An excerpt defining the docker registry auth could be something like:
runs: - name: deploy docker_registries_auth: 'myprivateregistry.example.com': username: 'username' password: from_variable: dockerpassword tasks: - ... - name: build docker image environment: DOCKERAUTH: from_variable: dockerpassword steps: # Steps to build and push the docker image - ... ...
When a run is created, the variable condition will be evaluated and the matching variable value will be used, then a secret matching the secret name will be used and the registry password will be set to its value. In this case the "dockerpassword" variable will be set both as the docker registries auth entry (all the images fetched by the executor for a task will use these credential) and also exported as an environment variable for a task.