Atlantis YAML Generator

atlantis-yaml-generator is a command-line tool designed to simplify the generation of Atlantis configuration files (atlantis.yaml).

It automates the process of detecting projects within your Terraform codebase, configuring workspaces, and generating the required configuration for the Atlantis CI/CD tool.

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Features

• Generate atlantis.yaml files with ease.
• Automatically detect projects and workspaces based on discovery mode rules.
• Customize configurations such as automerge, parallel plan/apply, and more.
• Flexible project inclusion and exclusion using regular expressions.
• Create an Atlantis project by taking into account the files modified in the PR. This approach ensures that only projects relevant to the current pull request are generated, avoiding the creation of any unrelated projects.

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Usage

Run the tool using the following command: atlantis-yaml-generator [flags]

Flag	Description	Equivalent envVar	Default Value
--automerge	Atlantis automerge config value.	AUTOMERGE	true
-r, --base-repo-name	Github Repo Name.	BASE_REPO_NAME
-o, --base-repo-owner	Github Repo Owner Name.	BASE_REPO_OWNER
-x, --excluded-projects	Atlantis regex filter to exclude projects.	EXCLUDED_PROJECTS
-d, --discovery-mode	mode used to discover projects	DISCOVERY_MODE	single-workspace
-t, --gh-token	Github Token Value.	GH_TOKEN
-h, --help	Help for atlantis-yaml-generator.
-z, --included-projects	Atlantis regex filter to only include projects.	INCLUDED_PROJECTS
-f, --output-file	Atlantis output file name.	OUTPUT_FILE	atlantis.yaml
-e, --output-type	Atlantis YAML output type [file stdout]	OUTPUT_TYPE	file
--parallel-apply	Atlantis parallel apply config value.	PARALLEL_APPLY	true
--parallel-plan	Atlantis parallel plan config value.	PARALLEL_PLAN	true
-q, --pattern-detector	Discover projects based on files or directories names.	PATTERN_DETECTOR	main.tf
-u, --pr-filter	Filter projects based on the PR changes (Only for github SCM).	PR_FILTER	false
-p, --pull-num	Github Pull Request Number to check diffs.	PULL_NUM
--terraform-base-dir	Basedir for terraform resources.	TERRAFORM_BASE_DIR	./
-v, --version	Version for atlantis-yaml-generator.
-m, --when-modified	Atlantis When modified (list of strings) to run autoplan.	WHEN_MODIFIED	**/*.tf,**/*.tfvars,**/*.json,**/*.tpl,**/*.tmpl,**/*.xml
-w, --workflow	Atlantis Workflow to be used.	WORKFLOW

Note that default values and required flags are defined in config.go

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Examples

Multi workspace workflow

# atlantis-yaml-generator -d multi-workspace -w myWorkflow --pattern-detector workspace_vars -e stdout

version: 3
automerge: true
parallel_apply: true
parallel_plan: true
projects:
    - name: project_one-dev
      workspace: dev
      workflow: myWorkflow
      dir: project_one
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'
    - name: project_one-production
      workspace: production
      workflow: myWorkflow
      dir: project_one
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'
    - name: project_one-staging
      workspace: staging
      workflow: myWorkflow
      dir: project_one
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'
    - name: project_two-production
      workspace: production
      workflow: myWorkflow
      dir: project_two
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'
    - name: project_two-staging
      workspace: staging
      workflow: myWorkflow
      dir: project_two
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'

Single workspace discovery mode

# atlantis-yaml-generator -d single-workspace -w myWorkflow -e stdout --pattern-detector main.tf

version: 3
automerge: true
parallel_apply: true
parallel_plan: true
projects:
    - name: project_one
      workspace: default
      workflow: myWorkflow
      dir: project_one
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmp

Multiple workspace workflow with regex project filtering

# atlantis-yaml-generator -w multi-workspace -e stdout --pattern-detector workspace_vars --included-projects "(^project_two-staging|production)$"

version: 3
automerge: true
parallel_apply: true
parallel_plan: true
projects:
    - name: project_one-production
      workspace: production
      workflow: multi-workspace
      dir: project_one
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'
    - name: project_two-production
      workspace: production
      workflow: multi-workspace
      dir: project_two
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'
    - name: project_two-staging
      workspace: staging
      workflow: multi-workspace
      dir: project_two
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'

Multi workspace workflow with PR filter

# atlantis-yaml-generator -w multi-workspace --pattern-detector workspace_vars -e stdout --pr-filter true --pull-num 1 --base-repo-name atlantis-yaml-generator --base-repo-owner totmicro --gh-token ghp_xxxx

version: 3
automerge: true
parallel_apply: true
parallel_plan: true
projects:
    - name: examples-multi-workspace/multiple-projects/project_one-dev
      workspace: dev
      workflow: multi-workspace
      dir: examples/multi-workspace/multiple-projects/project_one
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'

PR used in the above example

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Use environment variables to pass the sensitive args

When you run this command within an Atlantis workflow, it will make an effort to automatically identify the GitHub token by extracting it from the URL in the .git/config file.

When you run this command within an Atlantis workflow, base-repo base-repo-owner and pull-num parameters will be automatically identified. (Only github SCM)

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Discovery Modes

Currenlty atlantis-yaml-generator support 2 discovery modes:

• single-workspace: Intended for Terraform configurations that do not utilize multiple workspaces. In this context, the pattern detector parameters establish the criteria for identifying project folders. For instance, if the pattern-detector is set to main.tf (file), and this file is located at database/dev/main.tf, the resulting project would be labeled as database-env. Consequently, Terraform commands would be executed within the database/dev folder.
• multiple-workspace: Intended for Terraform configurations that utilize multiple workspaces. In this context, the pattern detector parameters establish the criteria for identifying project folders. For instance, if the pattern-detector is set to workspace_vars (folder), and there are several files located in this folder, i.e. (database/workspace_vars/dev.tf |database/workspace_vars/staging.tf ), the resulting projects would be labeled as (database-dev|database-staging). Consequently, Terraform commands would be executed within the database folder. Please be aware that in this scenario, the Atlantis workflow requires the use of the -var-file parameter, specifically in the form of -var-file=(workspace_vars/dev.tf|workspace_vars/staging.tf).

If there is the need for additional discovery modes, they can be easily added at code level. Current code is ready to easily add new discovery modes, while sharing common actions.

func detectProjectWorkspaces(foldersList []ProjectFolder, discoveryMode string, patternDetector string, changedFiles []string) (updatedFoldersList []ProjectFolder, err error) {
	// Detect project workspaces based on the discovery mode
	switch workflow {
	case "single-workspace":
		updatedFoldersList, err = singleWorkspaceDetectProjectWorkspaces(foldersList)
	case "multi-workspace":
		updatedFoldersList, err = multiWorkspaceDetectProjectWorkspaces(changedFiles, foldersList, patternDetector)
	}
	// You can add more workflows rules here if required
	return updatedFoldersList, err
}

Note that atlantis-yaml-detector will scan all files and folders under the current path. Alternatively you can pass the base path of terraform folders using --terraform-base-dir arg.

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Atlantis integration

Incorporating this generator into Atlantis requires setting up a pre-workflow-run as follows:

pre_workflow_hooks:
  - run: >
      atlantis-yaml-generator  -d single-workspace -w myWorkflow --pattern-detector main.tf

Sample output:

Files changed in the PR

project/one/main.tf
project/two/main.tf

Rendered atlantis.yaml file

version: 3
automerge: true
parallel_apply: true
parallel_plan: true
projects:
    - name: project-one
      workspace: default
      workflow: myWorkflow
      dir: project/one
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'
    - name: project-two
      workspace: default
      workflow: myWorkflow
      dir: project/two
      autoplan:
        enabled: true
        when_modified:
            - '**/*.tf'
            - '**/*.tfvars'
            - '**/*.json'
            - '**/*.tpl'
            - '**/*.tmpl'
            - '**/*.xml'

Additionally, it's essential to ensure that the atlantis-yaml-generator binary is included on your Atlantis server.

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Build

Prerequisites

Before you proceed, ensure you have the following installed:

• Go (1.20 or later)
• Make

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Quick Start

Clone this repository:

# git clone https://github.com/totmicro/atlantis-yaml-generator.git
# cd atlantis-yaml-generator

Install missing dependencies:

# make install

Run tests:

# make tests

Build the project:

# make build

To build binaries for different platforms:

# make build-all

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Makefile Commands

Here are the available commands in the Makefile:

• install: Install missing dependencies.
• tests: Run tests.
• coverage: Run tests and get coverage.
• build: Build the project.
• build-all: Build amd64 and arm64 binaries for Linux and Darwin.

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Limitations

• pr-filter parameter is specifically designed for use with the GitHub SCM.

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Contributing

Feel free to contribute to this project. We welcome your input!