How to Setup gitStream with GitLab

Prerequisites

GitLab cloud
GitLab runner v15 or higher
Login, or create a free account on the LinearB app, and follow the steps to connect gitStream Using a GitLab Integration.

GitLab Installation Overview

Designate a gitStream user account.
Create a CM configuration file.
Create a GitLab pipeline.
Install the gitStream service.

1. Designate a gitStream User Account

gitStream automation rules are executed on behalf of the user account configured when you install the gitStream service. This account must have the maintainer or owner role to the relevant repos.

We recommend creating a dedicated service account to control access to individual repos easily. You can also use your professional or personal GitLab account for this, which would result in all automations being executed under that account, which might also affect LinearB's metrics.

Use this account when you integrate gitStream

Make sure to use this account when authorizing GitLab in LinearB.

2. Create a CM Configuration File

You can set up gitStream for a single repo or your entire GitLab organization. Select the tab below for the instructions you want.

Single RepoGitLab Group

Single Repo Setup

Create a .cm/gitstream.cm rules file in your repository's default branch (usually master or main). This file will contain a YAML configuration that determines the workflows that run on the repo, and you can name it anything you want as long as it ends in .cm

Example Configuration

Here is an example of a gitStream configuration file you can use to setup some basic workflow automations.

# -*- mode: yaml -*-
# This example configuration for provides basic automations to get started with gitStream.
# View the gitStream quickstart for more examples: https://docs.gitstream.cm/examples/
manifest:
  version: 1.0


automations:
  # Add a label that indicates how many minutes it will take to review the PR.
  estimated_time_to_review:
    if:
      - true
    run:
      - action: add-label@v1
        args:
          label: "{{ calc.etr }} min review"
          color: {{ colors.red if (calc.etr >= 20) else ( colors.yellow if (calc.etr >= 5) else colors.green ) }}
  # Inform PR authors when they fail to reference Jira tickets in the PR title or description.
  label_missing_jira_info:
    if:
      - {{ not (has.jira_ticket_in_title or has.jira_ticket_in_desc) }}
    run:
      - action: add-label@v1
        args:
          label: "missing-jira"
          color: {{ colors.red }}
      - action: add-comment@v1
        args:
          comment: |
            This PR is missing a Jira ticket reference in the title or description.
            Please add a Jira ticket reference to the title or description of this PR.
  # Post a comment that lists the best experts for the files that were modified.
  explain_code_experts:
    if:
      - true
    run:
      - action: explain-code-experts@v1 
        args:
          gt: 10 


# +----------------------------------------------------------------------------+
# | Custom Expressions                                                         |
# | https://docs.gitstream.cm/how-it-works/#custom-expressions                 |
# +----------------------------------------------------------------------------+

calc:
  etr: {{ branch | estimatedReviewTime }}

has:
  jira_ticket_in_title: {{ pr.title | includes(regex=r/\b[A-Za-z]+-\d+\b/) }}
  jira_ticket_in_desc: {{ pr.description | includes(regex=r/atlassian.net\/browse\/\w{1,}-\d{3,4}/) }}

colors:
  red: 'b60205'
  yellow: 'fbca04'
  green: '0e8a16'

GitLab Group Setup

Group rules are ideal when you want to enforce consistent rules across every repo in your GitLab group. You can define them by creating a special repository named cm in the parent group for the git repositories you want to run gitStream on. Here, you can add automation files that will apply to all repositories within that group.

Create a cm project (repository) in your GitLab group, and create a gitstream.cm rules file in the root directory of your cm repository's default branch (usually master or main). This file will contain a YAML configuration that determines the workflows that run on your organization's repos. You can name the CM file anything you want as long as it ends in .cm

Configuration files go in the repo's root directory.

Unlike the set up instructions for a single repo, your .cm files should be placed in the repository's root directory.

Example Configuration

Here is an example of a gitStream configuration file you can use to setup some basic workflow automations.

# -*- mode: yaml -*-
# This example configuration for provides basic automations to get started with gitStream.
# View the gitStream quickstart for more examples: https://docs.gitstream.cm/examples/
manifest:
  version: 1.0


automations:
  # Add a label that indicates how many minutes it will take to review the PR.
  estimated_time_to_review:
    if:
      - true
    run:
      - action: add-label@v1
        args:
          label: "{{ calc.etr }} min review"
          color: {{ colors.red if (calc.etr >= 20) else ( colors.yellow if (calc.etr >= 5) else colors.green ) }}
  # Inform PR authors when they fail to reference Jira tickets in the PR title or description.
  label_missing_jira_info:
    if:
      - {{ not (has.jira_ticket_in_title or has.jira_ticket_in_desc) }}
    run:
      - action: add-label@v1
        args:
          label: "missing-jira"
          color: {{ colors.red }}
      - action: add-comment@v1
        args:
          comment: |
            This PR is missing a Jira ticket reference in the title or description.
            Please add a Jira ticket reference to the title or description of this PR.
  # Post a comment that lists the best experts for the files that were modified.
  explain_code_experts:
    if:
      - true
    run:
      - action: explain-code-experts@v1 
        args:
          gt: 10 


# +----------------------------------------------------------------------------+
# | Custom Expressions                                                         |
# | https://docs.gitstream.cm/how-it-works/#custom-expressions                 |
# +----------------------------------------------------------------------------+

calc:
  etr: {{ branch | estimatedReviewTime }}

has:
  jira_ticket_in_title: {{ pr.title | includes(regex=r/\b[A-Za-z]+-\d+\b/) }}
  jira_ticket_in_desc: {{ pr.description | includes(regex=r/atlassian.net\/browse\/\w{1,}-\d{3,4}/) }}

colors:
  red: 'b60205'
  yellow: 'fbca04'
  green: '0e8a16'

3. Create a GitLab Pipeline

Once your gitStream configuration file is set up, you need a GitLab CI configuration file to trigger gitStream automations. If you haven't already, create a cm project (repository) in your GitLab group. It should be created in the same group or a parent group of the target repositories. Create a .gitlab-ci.yml file in your new cm repository's default branch (usually master or main) and add the following configuration:

GitLab-Hosted runnersSelf-Managed Runners - ShellSelf-Managed Runners - Kubernetes

Gitlab-Hosted Runners

Use the following .gitlab-ci.yml

# Code generated by gitStream - DO NOT EDIT
stages:
  - gitstream-main
image: docker:latest
services:
  - docker:dind
before_script:
  - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY

gitstream-job:
  stage: gitstream-main
  only:
    variables:
      - $GITSTREAM_MAIN_JOB
  except:
    variables:
      - $GITSTREAM_BLOCK_MERGE
  script:
    - apk update && apk add git && apk add docker
    - git clone https://gitlab-ci-token:${CI_JOB_TOKEN}${repoUrl} gitstream/repo
    - git clone https://gitlab-ci-token:${CI_JOB_TOKEN}${cmUrl} gitstream/cm
    - cd gitstream && cd repo && git fetch --all && git checkout $base_ref && git pull && ls && git checkout $head_ref && git pull && ls
    - docker pull gitstream/rules-engine:latest
    - |
      docker run -v $CI_PROJECT_DIR/gitstream:/code \
      -e HEAD_REF=$head_ref \
      -e BASE_REF=$base_ref \
      -e CLIENT_PAYLOAD="$client_payload" \
      -e RULES_RESOLVER_URL=$resolver_url \
      -e RULES_RESOLVER_TOKEN=$resolver_token \
      -e DEBUG_MODE=true  gitstream/rules-engine:latest

Self-Managed Runners

First, register the runner with a tag, and use the named tag in the .gitlab-ci.yml file

Shell executors

Use the tag created above in the workflow file cm/.gitlab-ci.yml instead REGISTERED-TAG

# Code generated by gitStream - DO NOT EDIT
stages:
  - gitstream-main
image: docker:latest
services:
  - docker:dind
before_script:
  - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY

gitstream-job:
  stage: gitstream-main
  tags:
    - REGISTERED-TAG
  only:
    variables:
      - $GITSTREAM_MAIN_JOB
  except:
    variables:
      - $GITSTREAM_BLOCK_MERGE
  script:
    - apk update && apk add git && apk add docker
    - git clone https://gitlab-ci-token:${CI_JOB_TOKEN}${repoUrl} gitstream/repo
    - git clone https://gitlab-ci-token:${CI_JOB_TOKEN}${cmUrl} gitstream/cm
    - cd gitstream && cd repo && git fetch --all && git checkout $base_ref && git pull && ls && git checkout $head_ref && git pull && ls
    - docker pull gitstream/rules-engine:latest
    - |
      docker run -v $CI_PROJECT_DIR/gitstream:/code \
      -e HEAD_REF=$head_ref \
      -e BASE_REF=$base_ref \
      -e CLIENT_PAYLOAD="$client_payload" \
      -e RULES_RESOLVER_URL=$resolver_url \
      -e RULES_RESOLVER_TOKEN=$resolver_token \
      -e DEBUG_MODE=true  gitstream/rules-engine:latest

Self-Managed Runners

First, register the runner with a tag, and use the named tag in the .gitlab-ci.yml file

Kubernetes executors

Ensure your runner configuration (config.toml for example) has the followig:
```
[runners.kubernetes]
privileged = true
```

Use the tag created above in the workflow file cm/.gitlab-ci.yml instead REGISTERED-TAG

# Code generated by gitStream - DO NOT EDIT
variables:
  DOCKER_DRIVER: overlay2
  DOCKER_HOST: tcp://docker:2375
  DOCKER_TLS_CERTDIR: ""
stages:
  - gitstream-main

image: docker:latest
services:
  - name: docker:dind
    command: ["--mtu=1450", "--tls=false"]
before_script:
  - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY

gitstream-job:
  stage: gitstream-main
  tags:
    - REGISTERED-TAG
  only:
    variables:
      - $GITSTREAM_MAIN_JOB
  except:
    variables:
      - $GITSTREAM_BLOCK_MERGE
  script:
    - apk update && apk add git && apk add docker
    - git clone https://gitlab-ci-token:${CI_JOB_TOKEN}${repoUrl} gitstream/repo
    - git clone https://gitlab-ci-token:${CI_JOB_TOKEN}${cmUrl} gitstream/cm
    - cd gitstream && cd repo && git fetch --all && git checkout $base_ref && git pull && ls && git checkout $head_ref && git pull && ls
    - docker pull gitstream/rules-engine:latest
    - |
      docker run -v $CI_PROJECT_DIR/gitstream:/code \
      -e HEAD_REF=$head_ref \
      -e BASE_REF=$base_ref \
      -e CLIENT_PAYLOAD="$client_payload" \
      -e RULES_RESOLVER_URL=$resolver_url \
      -e RULES_RESOLVER_TOKEN=$resolver_token \
      -e DEBUG_MODE=true  gitstream/rules-engine:latest

Configuring the image location

By default, gitStream pulls the image from DockerHub each time it is invoked. You can configure gitStream to pull the docker image from your own registry, to allow faster build times and reduced bandwidth usage - especially for teams with high CI/CD throughput, by downloading the image and storing it in your own registry (ECR or K8S registry, for example) and changing the cm/.gitlab-ci.yml accordingly:

script:
- ...
- docker pull YOUR-REGISTRY-URL/gitstream/rules-engine:latest

The docker image can be pulled to your private repository from DockerHub.

Next Step

If you successfully complete these instructions, gitStream will now do these two things.

When a PR is created or changed, apply or update a label that provides an estimated time to review. Estimated Review Time label

When a suggest-reviewers label is applied to a PR, gitStream will comment with a list of code experts. Suggested reviewers

How gitStream Works

Read our guide, How gitStream Works, for a deeper understanding of gitStream's capabilities and how to leverage them fully and to get an overview of the gitStream syntax and automation lifecycle.

Additional Resources

Required GitLab Permissions

The required permissions are:

Permissions	Reason
Read/Write API	To get notified on MR changes and allow gitStream to approve MRs once all conditions are met
Read repository	To read and check rules over the code changes on monitored repositories
Read user profile	Used to identify users