terraform-google-pubsub-topic

A Terraform module for creating a Pub/Sub topic with GCP Monitoring notification channel integration and IAM bindings.

Features

• Create Pub/Sub topic for monitoring alerts
• Automatic GCP Monitoring notification channel creation
• IAM binding for GCP Monitoring service account
• Configurable message retention
• Ready for alert policy integration

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Assumptions

The project assumes the following:

• A basic understanding of Git.
• Git version >= 2.33.0.
• An existing GCP IAM user or role with access to create/update/delete resources defined in main.tf.
• GCloud CLI >= 465.0.0.
• A basic understanding of Terraform.
• Terraform version >= 1.3.0.
• (Optional - for local testing) A basic understanding of Make.
  • Make version >= GNU Make 3.81.
  • Important Note: This project includes a Makefile to speed up local development in Terraform. The make targets act as a wrapper around Terraform commands. As such, make has only been tested/verified on Linux/Mac OS. Though, it is possible to install make using Chocolatey, we do not guarantee this approach as it has not been tested/verified. You may use the commands in the Makefile as a guide to run each Terraform command locally on Windows.

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Test

Important Note: This project includes a Makefile to speed up local development in Terraform. The make targets act as a wrapper around Terraform commands. As such, make has only been tested/verified on Linux/Mac OS. Though, it is possible to install make using Chocolatey, we do not guarantee this approach as it has not been tested/verified. You may use the commands in the Makefile as a guide to run each Terraform command locally on Windows.

gcloud init # https://cloud.google.com/docs/authentication/gcloud
gcloud auth application-default login

# Copy the example tfvars and customize it
cp examples/simple/examples.tfvars examples/simple/terraform.tfvars
# Edit terraform.tfvars with your values

# Run terraform commands
make plan SVC=simple
make apply SVC=simple
make destroy SVC=simple

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Contributions

Contributions are always welcome. As such, this project uses the main branch as the source of truth to track changes.

Step 1. Clone this project.

# Using SSH
$ git clone git@github.com:nurdsoft/terraform-google-pubsub-topic.git

# Using HTTPS
$ git clone https://github.com/nurdsoft/terraform-google-pubsub-topic.git

Step 2. Checkout a feature branch: git checkout -b feature/abc.

Step 3. Validate the change/s locally by executing the steps defined under Test.

Step 4. If testing is successful, commit and push the new change/s to the remote.

$ git add file1 file2 ...

$ git commit -m "Adding some change"

$ git push --set-upstream origin feature/abc

Step 5. Once pushed, create a PR and assign it to a member for review.

• Important Note: It can be helpful to attach the terraform plan output in the PR.

Step 6. A team member reviews/approves/merges the change/s.

Step 7. Once merged, deploy the required changes as needed.

Step 8. Once deployed, verify that the changes have been deployed.

• If possible, please add a plan output using the feature branch so the member reviewing the PR has better visibility into the changes.

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Usage

module "pubsub_topic" {
  source = "git::https://github.com/nurdsoft/terraform-google-pubsub-topic.git?ref=main"

  project_id = "my-project"
  topic_name = "monitoring-alerts"
}

Resources Created

The module provisions the following resources:

Resource	Description
google_pubsub_topic	The Pub/Sub topic that receives alert payloads from GCP Monitoring
google_monitoring_notification_channel	A GCP Monitoring notification channel of type pubsub pointing to the topic
google_pubsub_topic_iam_member	Grants roles/pubsub.publisher to the GCP Monitoring service account so it can publish alerts to the topic

Examples

Example	Description
simple	Create a Pub/Sub topic with monitoring notification channel

Requirements

Name	Version
terraform	>= 1.3
google	>= 5.0

Providers

Name	Version
google	>= 5.0

Inputs

Required

Name	Description	Type	Default	Required
project_id	The GCP project ID to deploy resources into	string	n/a	yes

Optional

Name	Description	Type	Default	Required
topic_name	The name of the Pub/Sub topic that receives GCP Monitoring alert notifications	string	"monitoring-alerts"	no
message_retention_duration	How long to retain unacknowledged messages in the topic (e.g. "86400s" for 1 day)	string	"86400s"	no
notification_channel_display_name	Display name for the GCP Monitoring notification channel that publishes alerts to the Pub/Sub topic	string	"Monitoring Alerts Pub/Sub Channel"	no
monitoring_publisher_role	The IAM role granted to the GCP Monitoring service account to allow it to publish alert messages to the Pub/Sub topic	string	"roles/pubsub.publisher"	no

Outputs

Name	Description
topic_id	The fully-qualified ID of the Pub/Sub topic (e.g. projects/my-project/topics/my-topic)
topic_name	The short name of the Pub/Sub topic
notification_channel_id	The fully-qualified ID of the GCP Monitoring notification channel
notification_channel_name	The resource name of the GCP Monitoring notification channel. Pass this as notification_channels to the alert-policies module

Authors

Module is maintained by Nurdsoft.

License

Apache 2 Licensed. See LICENSE for full details.