philips-labs-github-runners

This component provisions the surrounding infrastructure for GitHub self-hosted runners.

Prerequisites

GitHub App installed on the organization
- For more details see Philips Lab's Setting up a GitHub App
- Ensure you create a PRIVATE KEY and store it in SSM, NOT to be confused with a Client Secret. Private Keys are created in the GitHub App Configuration and scrolling to the bottom.
GitHub App ID and private key stored in SSM under /pl-github-runners/id (or the value of var.github_app_id_ssm_path)
GitHub App Private Key stored in SSM (base64 encoded) under /pl-github-runners/key (or the value of var.github_app_key_ssm_path)

Usage

Stack Level: Regional Here's an example snippet for how to use this component.

components:
  terraform:
    philips-labs-github-runners:
      vars:
        enabled: true

The following will create

An API Gateway
Lambdas
SQS Queue
EC2 Launch Template instances

The API Gateway is registered as a webhook within the GitHub app. Which scales up or down, via lambdas, the EC2 Launch Template by the number of messages in the SQS queue.

Architecture

Modules

`webhook-github-app`

This is a fork of https://github.com/philips-labs/terraform-aws-github-runner/tree/main/modules/webhook-github-app.

We customized it until this PR is resolved as it does not update the GitHub App webhook until this is merged.

https://github.com/philips-labs/terraform-aws-github-runner/pull/3625

This module also requires an environment variable:

GH_TOKEN — a GitHub token must be set

This module also requires the gh CLI to be installed. Your Dockerfile can be updated to include the following to install it:

ARG GH_CLI_VERSION=2.39.1
# ...
ARG GH_CLI_VERSION
RUN apt-get update && apt-get install -y --allow-downgrades \
    gh="${GH_CLI_VERSION}-*"

By default, we leave this disabled, as it requires a GitHub token to be set. You can enable it by setting var.enable_update_github_app_webhook to true. When enabled, it will update the GitHub App webhook to point to the API Gateway. This can occur if the API Gateway is deleted and recreated.

When disabled, you will need to manually update the GitHub App webhook to point to the API Gateway. This is output by the component, and available via the webhook output under endpoint.

Variables

Required Variables

region (string) required: AWS region

Optional Variables

create_service_linked_role_spot (bool) optional

(optional) create the service linked role for spot instances that is required by the scale-up lambda.

Default value: true

enable_update_github_app_webhook (bool) optional

Enable updating the github app webhook

Default value: false

github_app_id_ssm_path (string) optional

Path to the github app id in SSM

Default value: "/pl-github-runners/id"

github_app_key_ssm_path (string) optional

Path to the github key in SSM

Default value: "/pl-github-runners/key"

instance_target_capacity_type (string) optional

Default lifecycle used for runner instances, can be either spot or on-demand.

Default value: "spot"

release_version (string) optional

Version of the application

Default value: "v5.4.0"

runner_extra_labels (list(string)) optional

Extra (custom) labels for the runners (GitHub). Labels checks on the webhook can be enforced by setting enable_workflow_job_labels_check. GitHub read-only labels should not be provided.

Default value:

[
  "default"
]

scale_up_reserved_concurrent_executions (number) optional

Amount of reserved concurrent executions for the scale-up lambda function. A value of 0 disables lambda from being triggered and -1 removes any concurrency limitations.

Default value: -1

ssm_paths optional

The root path used in SSM to store configuration and secrets.

Type:

object({
root       = optional(string, "github-action-runners")
app        = optional(string, "app")
runners    = optional(string, "runners")
use_prefix = optional(bool, true)
})

Default value: { }

Context Variables

The following variables are defined in the context.tf file of this module and part of the terraform-null-label pattern.

additional_tag_map (map(string)) optional

Additional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id.
This is for some rare cases where resources want additional configuration of tags
and therefore take a list of maps with tag key, value, and additional configuration.

Required: No

Default value: { }

attributes (list(string)) optional

ID element. Additional attributes (e.g. workers or cluster) to add to id,
in the order they appear in the list. New attributes are appended to the
end of the list. The elements of the list are joined by the delimiter
and treated as a single ID element.

Required: No

Default value: [ ]

context (any) optional

Single object for setting entire context at once.
See description of individual variables for details.
Leave string and numeric variables as null to use default value.
Individual variable settings (non-null) override settings in context object,
except for attributes, tags, and additional_tag_map, which are merged.

Required: No

Default value:

{
  "additional_tag_map": {},
  "attributes": [],
  "delimiter": null,
  "descriptor_formats": {},
  "enabled": true,
  "environment": null,
  "id_length_limit": null,
  "label_key_case": null,
  "label_order": [],
  "label_value_case": null,
  "labels_as_tags": [
    "unset"
  ],
  "name": null,
  "namespace": null,
  "regex_replace_chars": null,
  "stage": null,
  "tags": {},
  "tenant": null
}

delimiter (string) optional

Delimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.

Required: No

Default value: null

descriptor_formats (any) optional

Describe additional descriptors to be output in the descriptors output map.
Map of maps. Keys are names of descriptors. Values are maps of the form
\{<br/> format = string<br/> labels = list(string)<br/> \}
(Type is any so the map values can later be enhanced to provide additional options.)
format is a Terraform format string to be passed to the format() function.
labels is a list of labels, in order, to pass to format() function.
Label values will be normalized before being passed to format() so they will be
identical to how they appear in id.
Default is {} (descriptors output will be empty).

Required: No

Default value: { }

enabled (bool) optional

Set to false to prevent the module from creating any resources
Required: No

Default value: null

environment (string) optional

ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'
Required: No

Default value: null

id_length_limit (number) optional

Limit id to this many characters (minimum 6).
Set to 0 for unlimited length.
Set to null for keep the existing setting, which defaults to 0.
Does not affect id_full.

Required: No

Default value: null

label_key_case (string) optional

Controls the letter case of the tags keys (label names) for tags generated by this module.
Does not affect keys of tags passed in via the tags input.
Possible values: lower, title, upper.
Default value: title.

Required: No

Default value: null

label_order (list(string)) optional

The order in which the labels (ID elements) appear in the id.
Defaults to ["namespace", "environment", "stage", "name", "attributes"].
You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.

Required: No

Default value: null

label_value_case (string) optional

Controls the letter case of ID elements (labels) as included in id,
set as tag values, and output by this module individually.
Does not affect values of tags passed in via the tags input.
Possible values: lower, title, upper and none (no transformation).
Set this to title and set delimiter to "" to yield Pascal Case IDs.
Default value: lower.

Required: No

Default value: null

labels_as_tags (set(string)) optional

Set of labels (ID elements) to include as tags in the tags output.
Default is to include all labels.
Tags with empty values will not be included in the tags output.
Set to [] to suppress all generated tags.
Notes:
The value of the name tag, if included, will be the id, not the name.
Unlike other null-label inputs, the initial setting of labels_as_tags cannot be
changed in later chained modules. Attempts to change it will be silently ignored.

Required: No

Default value:

[
  "default"
]

name (string) optional

ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.
This is the only ID element not also included as a tag.
The "name" tag is set to the full id string. There is no tag with the value of the name input.

Required: No

Default value: null

namespace (string) optional

ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique
Required: No

Default value: null

regex_replace_chars (string) optional

Terraform regular expression (regex) string.
Characters matching the regex will be removed from the ID elements.
If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.

Required: No

Default value: null

stage (string) optional

ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'
Required: No

Default value: null

tags (map(string)) optional

Additional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.

Required: No

Default value: { }

tenant (string) optional

ID element (Rarely used, not included by default). A customer identifier, indicating who this instance of a resource is for
Required: No

Default value: null

Outputs

github_runners: Information about the GitHub runners.
queues: Information about the GitHub runner queues. Such as build_queue_arn the ARN of the SQS queue to use for the build queue.
ssm_parameters: Information about the SSM parameters to use to register the runner.
webhook: Information about the webhook to use to register the runner.

Dependencies

Requirements

terraform, version: >= 1.0.0
aws, version: >= 4.9.0, < 6.0.0
local, version: >= 2.4.0
random, version: >= 3.0

Providers

random, version: >= 3.0

Modules

Name	Version	Source	Description
`github_runner`	6.1.0	`philips-labs/github-runner/aws`	n/a
`iam_roles`	latest	`../account-map/modules/iam-roles`	n/a
`module_artifact`	0.8.0	`cloudposse/module-artifact/external`	n/a
`store_read`	0.13.0	`cloudposse/ssm-parameter-store/aws`	n/a
`this`	0.25.0	`cloudposse/label/null`	n/a
`vpc`	1.8.0	`cloudposse/stack-config/yaml//modules/remote-state`	n/a
`webhook_github_app`	6.1.0	`philips-labs/github-runner/aws//modules/webhook-github-app`	n/a

Resources

The following resources are used by this module:

random_id.webhook_secret (resource)

Data Sources

The following data sources are used by this module:

Prerequisites​

Usage​

Modules​

webhook-github-app​

Variables​

Required Variables​

Optional Variables​

Context Variables​

Outputs​

Dependencies​

Requirements​

Providers​

Modules​

Resources​

Data Sources​

Prerequisites

Usage

Modules

`webhook-github-app`

Variables

Required Variables

Optional Variables

Context Variables

Outputs

Dependencies

Requirements

Providers

Modules

Resources

Data Sources