nick4fake / terraform-google-dataflow

Google Dataflow Terraform Module

This module handles opiniated Dataflow job configuration and deployments.

The resources/services/activations/deletions that this module will create/trigger are:

• Create a GCS bucket for temporary job data
• Create a Dataflow job

Usage

Before using this module, one should get familiar with the google_dataflow_job’s Notes on “destroy”/”apply” as the behavior is atypical when compared to other resources.

Assumption

The module is made to be used with the template_gcs_path as the staging location. Hence, one assumption is that, before using this module, you already have working Dataflow job template(s) in GCS staging location(s).

There are examples included in the examples folder but simple usage is as follows:

module "dataflow-job" {
  source  = "terraform-google-modules/dataflow/google"
  version = "0.1.0"
 
  project_id  = "<project_id>"
  job_name = "<job_name>"
  on_delete = "cancel"
  zone = "us-central1-a"
  max_workers = 1
  template_gcs_path =  "gs://<path-to-template>"
  temp_gcs_location = "gs://<gcs_path_temp_data_bucket"
  parameters = {
        bar = "example string"
        foo = 123
  }
}

Then perform the following commands on the root folder:

• terraform init to get the plugins
• terraform plan to see the infrastructure plan
• terraform apply to apply the infrastructure build
• terraform destroy to destroy the built infrastructure

Inputs

Name	Description	Type	Default	Required
machine_type	The machine type to use for the job.	string	""	no
max_workers	The number of workers permitted to work on the job. More workers may improve processing speed at additional cost.	string	"1"	no
name	The name of the dataflow job	string	n/a	yes
network_self_link	The network self link to which VMs will be assigned.	string	"default"	no
on_delete	One of drain or cancel. Specifies behavior of deletion during terraform destroy. The default is cancel.	string	"cancel"	no
parameters	Key/Value pairs to be passed to the Dataflow job (as used in the template).	map	<map>	no
project_id	The project in which the resource belongs. If it is not provided, the provider project is used.	string	n/a	yes
region	The bucket's region location	string	"us-central1"	no
service_account_email	The Service Account email that will be used to identify the VMs in which the jobs are running	string	""	no
subnetwork_self_link	The subnetwork self link to which VMs will be assigned.	string	""	no
temp_gcs_location	A writeable location on GCS for the Dataflow job to dump its temporary data.	string	n/a	yes
template_gcs_path	The GCS path to the Dataflow job template.	string	n/a	yes
zone	The zone in which the created job should run. If it is not provided, the provider zone is used.	string	"us-central1-a"	no

Outputs

Name	Description
id	The unique Id of the newly created Dataflow job
name	The name of the dataflow job
state	The state of the newly created Dataflow job
temp_gcs_location	The GCS path for the Dataflow job's temporary data.
template_gcs_path	The GCS path to the Dataflow job template.

Requirements

Before this module can be used on a project, you must ensure that the following pre-requisites are fulfilled:

1. Terraform is installed on the machine where Terraform is executed.
2. The Service Account you execute the module with has the right permissions.
3. The necessary APIs are active on the project.
4. A working Dataflow template in uploaded in a GCS bucket

The project factory can be used to provision projects with the correct APIs active.

Software Dependencies

Terraform

• Terraform 0.11.x
• terraform-provider-google plugin v2.0.0

Configure a Service Account to execute the module

In order to execute this module you must have a Service Account with the following project roles:

• roles/dataflow.admin
• roles/iam.serviceAccountUser
• roles/storage.admin

Configure a Controller Service Account to create the job

If you want to use the service_account_email input to specify a service account that will identify the VMs in which the jobs are running, the service account will need the following project roles:

• roles/dataflow.worker
• roles/storage.objectAdmin

Enable APIs

In order to launch a Dataflow Job, the Dataflow API must be enabled:

• Dataflow API - dataflow.googleapis.com
• Compute Engine API: compute.googleapis.com

Install

Terraform

Be sure you have the correct Terraform version (0.11.x), you can choose the binary here:

• https://releases.hashicorp.com/terraform/

Testing

Requirements

• bundler
• gcloud
• terraform-docs 0.6.0

Autogeneration of documentation from .tf files

Run

make generate_docs

Integration test

Integration tests are run though test-kitchen, kitchen-terraform, and InSpec.

test-kitchen instances are defined in .kitchen.yml. The test-kitchen instances in test/fixtures/ wrap identically-named examples in the examples/ directory.

Setup

1. Configure the test fixtures
2. Download a Service Account key with the necessary permissions and put it in the module's root directory with the name credentials.json.
3. Build the Docker container for testing:

make docker_build_kitchen_terraform

4. Run the testing container in interactive mode:

make docker_run

The module root directory will be loaded into the Docker container at /cft/workdir/. 5. Run kitchen-terraform to test the infrastructure:

1. kitchen create creates Terraform state and downloads modules, if applicable.
2. kitchen converge creates the underlying resources. Run kitchen converge <INSTANCE_NAME> to create resources for a specific test case.
3. kitchen verify tests the created infrastructure. Run kitchen verify <INSTANCE_NAME> to run a specific test case.
4. kitchen destroy tears down the underlying resources created by kitchen converge. Run kitchen destroy <INSTANCE_NAME> to tear down resources for a specific test case.

Alternatively, you can simply run make test_integration_docker to run all the test steps non-interactively.

Test configuration

Each test-kitchen instance is configured with a variables.tfvars file in the test fixture directory. For convenience, since all of the variables are project-specific, these files have been symlinked to test/fixtures/shared/terraform.tfvars. Similarly, each test fixture has a variables.tf to define these variables, and an outputs.tf to facilitate providing necessary information for inspec to locate and query against created resources.

Each test-kitchen instance creates necessary fixtures to house resources.

Autogeneration of documentation from .tf files

Run

make generate_docs

Linting

The makefile in this project will lint or sometimes just format any shell, Python, golang, Terraform, or Dockerfiles. The linters will only be run if the makefile finds files with the appropriate file extension.

All of the linter checks are in the default make target, so you just have to run

make -s

The -s is for 'silent'. Successful output looks like this

Running shellcheck
Running flake8
Running go fmt and go vet
Running terraform validate
Running hadolint on Dockerfiles
Checking for required files
Testing the validity of the header check
..
----------------------------------------------------------------------
Ran 2 tests in 0.026s

OK
Checking file headers
The following lines have trailing whitespace

The linters are as follows:

• Shell - shellcheck. Can be found in homebrew
• Python - flake8. Can be installed with 'pip install flake8'
• Golang - gofmt. gofmt comes with the standard golang installation. golang is a compiled language so there is no standard linter.
• Terraform - terraform has a built-in linter in the 'terraform validate' command.
• Dockerfiles - hadolint. Can be found in homebrew