GitLab CI template for Google Cloud Platform

This project implements a GitLab CI/CD template to deploy your application to the Google Cloud platform.

Usage

In order to include this template in your project, add the following to your gitlab-ci.yml:

include:
  - project: 'to-be-continuous/gcloud'
    ref: '5.0.1'
    file: '/templates/gitlab-ci-gcloud.yml'

Understand

This chapter introduces key notions and principle to understand how this template works.

Managed deployment environments

This template implements continuous delivery/continuous deployment for projects hosted on Google Cloud Platform.

It allows you to manage automatic deployment & cleanup of standard predefined environments. Each environment can be enabled/disabled by configuration. If you're not satisfied with predefined environments and/or their associated Git workflow, you may implement you own environments and workflow, by reusing/extending the base (hidden) jobs. This is advanced usage and will not be covered by this documentation.

The following chapters present the managed predefined environments and their associated Git workflow.

Review environments

The template supports review environments: those are dynamic and ephemeral environments to deploy your ongoing developments (a.k.a. feature or topic branches).

When enabled, it deploys the result from upstream build stages to a dedicated and temporary environment. It is only active for non-production, non-integration branches.

It is a strict equivalent of GitLab's Review Apps feature.

It also comes with a cleanup job (accessible either from the environments page, or from the pipeline view).

Integration environment

If you're using a Git Workflow with an integration branch (such as Gitflow), the template supports an integration environment.

When enabled, it deploys the result from upstream build stages to a dedicated environment. It is only active for your integration branch (develop by default).

Production environments

Lastly, the template supports 2 environments associated to your production branch (master or main by default):

• a staging environment (an iso-prod environment meant for testing and validation purpose),
• the production environment.

You're free to enable whichever or both, and you can also choose your deployment-to-production policy:

• continuous deployment: automatic deployment to production (when the upstream pipeline is successful),
• continuous delivery: deployment to production can be triggered manually (when the upstream pipeline is successful).

Supported authentication methods

The Google Cloud Platform template supports two kinds of authentication:

1. basic authentication with Service Account key file,
2. or federated authentication using OpenID Connect.

Service account authentication

To use this authentication method, simply generate and provide Service Account key file as secret GitLab CI/CD variables (of type File), using the appropriate variables (see doc below).

Can be provided globally and/or per environment.

Federated authentication using OpenID Connect

The GCP template supports a federated authentication using OpenID Connect.

If you wish to use this authentication mode, please activate and configure the OIDC variant.

Deployment context variables

In order to manage the various deployment environments, this template provides a couple of dynamic variables that you might use in your hook scripts, deployment manifests and other deployment resources:

• ${environment_type}: the current deployment environment type (review, integration, staging or production)
• ${environment_name}: a generated application name to use for the current deployment environment (ex: myapp-review-fix-bug-12 or myapp-staging) - details below

Generated environment name

The ${environment_name} variable is generated to designate each deployment environment with a unique and meaningful application name. By construction, it is suitable for inclusion in DNS, URLs, Kubernetes labels... It is built from:

• the application base name (defaults to $CI_PROJECT_NAME but can be overridden globally and/or per deployment environment - see configuration variables)
• GitLab predefined $CI_ENVIRONMENT_SLUG variable (sluggified name, truncated to 24 characters)

The ${environment_name} variable is then evaluated as:

• <app base name> for the production environment
• <app base name>-$CI_ENVIRONMENT_SLUG for all other deployment environments
• 💡 ${environment_name} can also be overriden per environment with the appropriate configuration variable

Examples (with an application's base name myapp):

Deployment and cleanup scripts

The Google Cloud template requires you to provide a shell script that fully implements your application deployment and cleanup using the gcloud CLI and all other tools available in the selected Docker image.

The deployment script is searched as follows:

1. look for a specific gcp-deploy-$environment_type.sh in the $GCP_SCRIPTS_DIR directory in your project (e.g. gcp-deploy-staging.sh for staging environment),
2. if not found: look for a default gcp-deploy.sh in the $GCP_SCRIPTS_DIR directory in your project,
3. if not found: the deployment job will fail.

The cleanup script is searched as follows:

1. look for a specific gcp-cleanup-$environment_type.sh in the $GCP_SCRIPTS_DIR directory in your project (e.g. gcp-cleanup-staging.sh for staging environment),
2. if not found: look for a default gcp-cleanup.sh in the $GCP_SCRIPTS_DIR directory in your project,
3. if not found: the cleanup job will fail.

ℹ️ Your deployment (and cleanup) scripts have to be able to cope with various environments, each with different application names, exposed routes, settings, ... Part of this complexity can be handled by the lookup policies described above (ex: one script per env) and also by using available environment variables:

1. deployment context variables provided by the template:
   • ${environment_type}: the current environment type (review, integration, staging or production)
   • ${environment_name}: the application name to use for the current environment (ex: myproject-review-fix-bug-12 or myproject-staging)
   • ${hostname}: the environment hostname, extracted from the current environment url (after late variable expansion - see below)
2. any GitLab CI variable
3. any custom variable (ex: ${SECRET_TOKEN} that you have set in your project CI/CD variables)

Environments URL management

The GCP template supports two ways of providing your environments url:

• a static way: when the environments url can be determined in advance, probably because you're exposing your routes through a DNS you manage,
• a dynamic way: when the url cannot be known before the deployment job is executed.

The static way can be implemented simply by setting the appropriate configuration variable(s) depending on the environment (see environments configuration chapters):

• $GCP_ENVIRONMENT_URL to define a default url pattern for all your envs,
• $GCP_REVIEW_ENVIRONMENT_URL, $GCP_INTEG_ENVIRONMENT_URL, $GCP_STAGING_ENVIRONMENT_URL and $GCP_PROD_ENVIRONMENT_URL to override the default.

ℹ️ Each of those variables support a late variable expansion mechanism with the %{somevar} syntax, allowing you to use any dynamically evaluated variables such as ${environment_name}.

Example:

variables:
  GCP_BASE_APP_NAME: "wonderapp"
  # global url for all environments
  GCP_ENVIRONMENT_URL: "https://%{environment_name}.nonprod.acme.domain"
  # override for prod (late expansion of $GCP_BASE_APP_NAME not needed here)
  GCP_PROD_ENVIRONMENT_URL: "https://$GCP_BASE_APP_NAME.acme.domain"
  # override for review (using separate resource paths)
  GCP_REVIEW_ENVIRONMENT_URL: "https://wonderapp-review.nonprod.acme.domain/%{environment_name}"

To implement the dynamic way, your deployment script shall simply generate a environment_url.txt file in the working directory, containing only the dynamically generated url. When detected by the template, it will use it as the newly deployed environment url.

Deployment output variables

Each deployment job produces output variables that are propagated to downstream jobs (using dotenv artifacts):

• $environment_type: set to the type of environment (review, integration, staging or production),
• $environment_name: the application name (see below),
• $environment_url: set to the environment URL (whether determined statically or dynamically).

Those variables may be freely used in downstream jobs (for instance to run acceptance tests against the latest deployed environment).

You may also add and propagate your own custom variables, by pushing them to the gcloud.env file in your deployment script.

Configuration reference

Secrets management

Here are some advices about your secrets (variables marked with a 🔒):

1. Manage them as project or group CI/CD variables:
   • masked to prevent them from being inadvertently displayed in your job logs,
   • protected if you want to secure some secrets you don't want everyone in the project to have access to (for instance production secrets).
2. In case a secret contains characters that prevent it from being masked, simply define its value as the Base64 encoded value prefixed with @b64@: it will then be possible to mask it and the template will automatically decode it prior to using it.
3. Don't forget to escape special characters (ex: $ -> $$).

Global configuration

The Google Cloud template uses some global configuration used throughout all jobs.

Review environments configuration

Review environments are dynamic and ephemeral environments to deploy your ongoing developments (a.k.a. feature or topic branches).

They are disabled by default and can be enabled by setting the GCP_REVIEW_PROJECT variable (see below).

Here are variables supported to configure review environments:

Integration environment configuration

The integration environment is the environment associated to your integration branch (develop by default).

It is disabled by default and can be enabled by setting the GCP_INTEG_PROJECT variable (see below).

Here are variables supported to configure the integration environment:

Staging environment configuration

The staging environment is an iso-prod environment meant for testing and validation purpose associated to your production branch (main or master by default).

It is disabled by default and can be enabled by setting the GCP_STAGING_PROJECT variable (see below).

Here are variables supported to configure the staging environment:

Production environment configuration

The production environment is the final deployment environment associated with your production branch (main or master by default).

It is disabled by default and can be enabled by setting the GCP_PROD_PROJECT variable (see below).

Here are variables supported to configure the production environment:

Examples

Google AppEngine application

Context

Let's imagine a backend service:

• named coockedoodledoo,
• developped in whichever language,
• part of project named farmvoices
• hosted on Google AppEngine with project ID farmvoices-12345
• with review, staging and production environments enabled.

.gitlab-ci.yml

include:
  # Include Google Cloud template
  - project: 'to-be-continuous/gcloud'
    ref: '5.0.1'
    file: '/templates/gitlab-ci-gcloud.yml'
  ...

# Global variables
variables:
  ...

  # Google Cloud
  # GCP_KEY_FILE defined as secret CI/CD variable
  GCP_REVIEW_PROJECT: "farm-12345" # enable review env
  GCP_STAGING_PROJECT: "farm-12345" # enable staging env
  GCP_PROD_PROJECT: "farm-12345" # enable production env
  GCP_STAGING_ENVIRONMENT_URL: "https://staging-dot-coockedoodledoo-dot-farmvoices-12345.ew.r.appspot.com"
  GCP_PROD_ENVIRONMENT_URL: "https://coockedoodledoo-dot-farmvoices-12345.ew.r.appspot.com"

  # Postman
  REVIEW_ENABLED: "true"

# define review environment url (uses $CI_ENVIRONMENT_SLUG as app version)
gcp-review:
  environment:
    url: "https://$CI_ENVIRONMENT_SLUG-dot-coockedoodledoo-dot-farmvoices-12345.ew.r.appspot.com"

AppEngine manifest

# Google AppEngine manifest
# see: https://cloud.google.com/appengine/docs/standard/java11/config/appref
runtime: TODO # depends on languages
instance_class: F2
service: coockedoodledoo

...

variables:
  # this is an example of hardcoded (non-sensitive) configuration variable
  SOME_CONFIG: "some-value"
  # this is an example of variabilized (secret) configuration variable
  # will be replaced programmatically during deployment
  SOME_SECRET: "${SOME_SECRET}"

hook scripts

gcp-deploy.sh

This script is executed by the template to perform the application(s) deployment based on gcloud CLI.

#!/usr/bin/env bash
echo "[gcp-deploy] Deploy burger/$CI_ENVIRONMENT_SLUG..."

# prepare GAE deployment directory (copy build output)
mkdir -p gae
cp build/* gae

# copy manifest with variables substitution
awk '{while(match($0,"[$]{[^}]*}")) {var=substr($0,RSTART+2,RLENGTH-3);gsub("[$]{"var"}",ENVIRON[var])}}1' < src/app.yaml > gae/app.yaml

# gcloud deploy
# use $CI_ENVIRONMENT_SLUG as the version
cd gae

if [[ "$CI_ENVIRONMENT_SLUG" == "production" ]]
then
  promote_opt="--promote"
else
  promote_opt="--no-promote"
fi

gcloud --quiet app deploy --project=${gcp_project_id} --version=${CI_ENVIRONMENT_SLUG} $promote_opt

gcp-cleanup.sh

This script is executed by the template to perform the application(s) cleanup based on gcloud CLI (review env only).

#!/usr/bin/env bash
echo "[gcp-cleanup] Cleanup burger/$CI_ENVIRONMENT_SLUG..."

# use $CI_ENVIRONMENT_SLUG as the version
gcloud --quiet app versions delete --project=${gcp_project_id} --service=coockedoodledoo ${CI_ENVIRONMENT_SLUG}

Variants

The Google Cloud template can be used in conjunction with template variants to cover specific cases.

OIDC variant

This variant enables federated authentication using OpenID Connect.

If you wish to use this authentication mode, please follow carefully the GitLab guide, then configure appropriately the related variables:

• GPC_OIDC_PROVIDER / GPC_OIDC_ACCOUNT for any global/common access,
• GPC_<env>_OIDC_PROVIDER / GPC_<env>_OIDC_ACCOUNT if you wish to use separate settings with any of your environments.

The GPC_OIDC_PROVIDER & GPC_<env>_OIDC_PROVIDER variable shall be of the form:

projects/<PROJECT_NUMBER>/locations/global/workloadIdentityPools/<POOL_ID>/providers/<PROVIDER_ID>

The following commands may help you retrieve the different values:

• gcloud projects describe $GCP_PROJECT --format="value(projectNumber)" will return the PROJECT_NUMBER value
• gcloud iam workload-identity-pools list --location=global --format="value(name)" will list you POOL_IDs available on your GCP_PROJECT
• gcloud iam workload-identity-pools providers list --workload-identity-pool=<my-pool> --location=global --format="value(name)" will return the list of available PROVIDER_ID for one POOL_ID

Configuration

The variant supports the following configuration:

Example

include:
  # main template
  - project: 'to-be-continuous/gcloud'
    ref: '5.0.1'
    file: '/templates/gitlab-ci-gcloud.yml'
  # Vault variant
  - project: 'to-be-continuous/gcloud'
    ref: '5.0.1'
    file: '/templates/gitlab-ci-gcloud-oidc.yml'

variables:
  # audience claim for JWT
  GCP_OIDC_AUD: "https://iam.googleapis.com"
  # common OIDC config for non-prod envs
  GCP_OIDC_PROVIDER: "projects/<gcp_nonprod_proj_id>/locations/global/workloadIdentityPools/<pool_id>/providers/<provider_id>"
  GCP_OIDC_ACCOUNT: "<name>@$<gcp_nonprod_proj_id>.iam.gserviceaccount.com"
  # specific OIDC config for prod
  GCP_PROD_OIDC_PROVIDER: "projects/<gcp_prod_proj_id>/locations/global/workloadIdentityPools/<pool_id>/providers/<provider_id>"
  GCP_PROD_OIDC_ACCOUNT: "<name>@$<gcp_prod_proj_id>.iam.gserviceaccount.com"

Vault variant

This variant allows delegating your secrets management to a Vault server.

Configuration

In order to be able to communicate with the Vault server, the variant requires the additional configuration parameters:

Usage

Then you may retrieve any of your secret(s) from Vault using the following syntax:

@url@http://vault-secrets-provider/api/secrets/{secret_path}?field={field}

With:

Example

include:
  # main template
  - project: 'to-be-continuous/gcloud'
    ref: '5.0.1'
    file: '/templates/gitlab-ci-gcloud.yml'
  # Vault variant
  - project: 'to-be-continuous/gcloud'
    ref: '5.0.1'
    file: '/templates/gitlab-ci-gcloud-vault.yml'

variables:
    # audience claim for JWT
    VAULT_OIDC_AUD: "https://vault.acme.host"
    # Secrets managed by Vault
    SOME_SECRET_USED_IN_MY_APP: "@url@http://vault-secrets-provider/api/secrets/b7ecb6ebabc231/prod/gcloud/secret?field=my.app.secret"
    VAULT_BASE_URL: "https://vault.acme.host/v1"
    # $VAULT_ROLE_ID and $VAULT_SECRET_ID defined as a secret CI/CD variable