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Project and Folder Factory

This module implements end-to-end creation processes for a folder hierarchy, projects and billing budgets via YAML data configurations.

It supports

  • filesystem-driven folder hierarchy exposing the full configuration options available in the folder module
  • multiple project creation and management exposing the full configuration options available in the project module, including KMS key grants and VPC-SC perimeter membership
  • optional per-project service account and bucket management including basic IAM grants
  • optional billing budgets factory and budget/project associations
  • cross-referencing of hierarchy folders in projects
  • optional per-project IaC configuration

The factory is implemented as a thin data translation layer for the underlying modules, so that no "magic" or hidden side effects are implemented in code, and debugging or integration of new features are simple.

The code is meant to be executed by a high level service accounts with powerful permissions:

  • folder admin permissions for the hierarchy
  • project creation on the nodes (folder or org) where projects will be defined
  • Shared VPC connection if service project attachment is desired
  • billing cost manager permissions to manage budgets and monitoring permissions if notifications should also be managed here

Contents

Folder hierarchy

The hierarchy supports up to three levels of folders, which are defined via filesystem directories each including a _config.yaml files detailing their attributes.

The hierarchy factory is configured via the factories_config.folders_data_path variable, which sets the the path containing the YAML definitions for folders.

Parent ids for top-level folders can either be set explicitly (e.g. folders/12345678) or via substitutions, by referring to keys in the context.folder_ids variable. The special default key in the substitutions folder variable is used if present and no folder id/key has been specified in the YAML.

Filesystem directories can also contain project definitions in the same YAML format described below. This approach must be used with caution and is best adopted for stable scenarios, as problems in the filesystem hierarchy definitions might result in the project files not being read and the resources being deleted by Terraform.

Refer to the example below for actual examples of the YAML definitions.

Projects

The project factory is configured via the factories_config.projects_data_path variable, and project files are also read from the hierarchy describe in the previous section when enabled. The YAML format mirrors the project module, refer to the example below for actual examples of the YAML definitions.

Factory-wide project defaults, merges, optionals

In addition to the YAML-based project configurations, the factory accepts three additional sets of inputs via Terraform variables:

  • the data_defaults variable allows defining defaults for specific project attributes, which are only used if the attributes are not passed in via YAML
  • the data_overrides variable works similarly to defaults, but the values specified here take precedence over those in YAML files
  • the data_merges variable allows specifying additional values for map or set based variables, which are merged with the data coming from YAML

Some examples on where to use each of the three sets are provided below.

Service accounts and buckets

Service accounts and GCS buckets can be managed as part of each project's YAML configuration. This allows creation of default service accounts used for GCE instances, in firewall rules, or for application-level credentials without resorting to a separate Terraform configuration.

Each service account is represented by one key and a set of optional key/value pairs in the service_accounts top-level YAML map, which exposes most of the variables available in the iam-service-account module. Both the display_name and iam_self_roles attributes are optional.

service_accounts:
  be-0: {}
  fe-1:
    display_name: GCE frontend service account.
    iam_self_roles:
      - roles/storage.objectViewer
    iam_project_roles:
      my-host-project:
        - roles/compute.networkUser
  terraform-rw: {}

Each bucket is represented by one key and a set of optional key/value pairs in the buckets top-level YAML map, which exposes most of the variables available in the gcs module. Bucket location, storage class and a few other attributes can be defaulted/enforced via project factory level variables.

buckets:
  state:
    location: europe-west8
    iam:
      roles/storage.admin:
        - terraform-rw

Automation project and resources

Other than creating automation resources within the project via the service_accounts and buckets attributes, this module also support management of automation resources created in a separate controlling project. This allows grating broad roles on the project, while still making sure that the automation resources used for Terraform cannot be manipulated from the same identities.

Automation resources are defined via the automation attribute in project configurations, which supports:

  • a mandatory project attribute to define the external controlling project; this attribute does not support interpolation and needs to be explicit
  • an optional service_accounts list where each element defines a service account in the controlling project
  • an optional bucket which defines a bucket in the controlling project, and the map of roles/principals in the corresponding value assigned on the created bucket; principals can refer to the created service accounts by key

Service accounts and buckets are prefixed with the project name. Service accounts use the key specified in the YAML file as a suffix, while buckets use a default tf-state suffix.

# file name: prod-app-example-0
# prefix via factory defaults: foo
# project id: foo-prod-app-example-0
billing_account: 012345-67890A-BCDEF0
parent: folders/12345678
services:
  - compute.googleapis.com
  - stackdriver.googleapis.com
iam:
  roles/owner:
    - rw
  roles/viewer:
    - ro
automation:
  project: foo-prod-iac-core-0
  service_accounts:
    # sa name: foo-prod-app-example-0-rw
    rw:
      description: Read/write automation sa for app example 0.
    # sa name: foo-prod-app-example-0-ro
    ro:
      description: Read-only automation sa for app example 0.
  bucket:
    # bucket name: foo-prod-app-example-0-tf-state
    description: Terraform state bucket for app example 0.
    iam:
      roles/storage.objectCreator:
        - rw
      roles/storage.objectViewer:
        - rw
        - ro
        - group:[email protected]

Billing budgets

The billing budgets factory integrates the [billing-account`](../billing-account/) module functionality, and adds support for easy referencing budgets in project files.

To enable support for billing budgets, set the billing account id, optional notification channels, and the data folder for budgets in the factories_config.budgets variable, then create billing budgets using YAML definitions following the format described in the billing-account module.

Once budgets are defined, they can be referenced in a project file using their file name:

billing_account: 012345-67890A-BCDEF0
labels:
 app: app-1
 team: foo
parent: folders/12345678
services:
  - container.googleapis.com
  - storage.googleapis.com
billing_budgets:
  - test-100

A simple billing budget example is show in the example below.

Interpolation in YAML configuration attributes

Interpolation allow referring via short mnemonic names to resources which are either created at runtime, or externally managed.

This feature has two main benefits:

  • being able to refer to resource ids which cannot be known before creation, for example project automation service accounts in IAM bindings
  • making YAML configuration files more easily readable and portable, by using mnemonic keys which are not specific to an organization or project

One example of both types of contexts is in this project snippet. The automation service account is used in IAM bindings via its rw key, while the parent folder is set by referring to its path in the hierarchy factory.

parent: teams/team-a
iam:
  "roles/owner":
    - rw
automation:
  project: ta-app0-0
  service_accounts:
    rw:
      description: Read/write automation sa for team a app 0.
  buckets:
    state:
      description: Terraform state bucket for team a app 0.
      iam:
        roles/storage.objectCreator:
          - rw

Interpolations leverage contexts from two separate sources: an internal set for resources managed by the project factory (folders, service accounts, etc.), and an external user-defined set passed in via the factories_config.context variable.

The following table lists the available context interpolations. External contexts are passed in via the factories_config.contexts variable. IAM principals are interpolated in all IAM attributes except iam_by_principal. First two columns show for which attribute of which resource context is interpolated. external contexts column show in which map passed as var.factories_config.context key will be looked up.

  • Internally created folders creates keys under ${folder_name_1}[/${folder_name_2}/${folder_name_3}]
  • IAM principals are resolved within context of managed project or use ${project}/${service_account} to refer service account from other projects managed by the same project factory instance.
resource attribute external contexts internal contexts
folder parent folder_ids implicit through folder structure
folder IAM principals iam_principals
folder tag bindings tag_values
project parent folder_ids internally created folders
project Shared VPC host vpc_host_projects
project Shared VPC IAM iam_principals project service accounts
IaC service accounts
other project service accounts
other project IaC service accounts
project tag bindings tag_values
project IAM principals iam_principals project service accounts
IaC service accounts
other project service accounts
other project IaC service accounts
bucket IAM principals iam_principals project service accounts
IaC service accounts
other project service accounts
other project IaC service accounts
service account IAM projects vpc_host_projects
IaC bucket IAM principals iam_principals IaC service accounts
IaC service account IAM principals iam_principals

Example

The module invocation using all optional features:

module "project-factory" {
  source = "./fabric/modules/project-factory"
  # use a default billing account if none is specified via yaml
  data_defaults = {
    billing_account  = var.billing_account_id
    storage_location = "EU"
  }
  # make sure the environment label and stackdriver service are always added
  data_merges = {
    labels = {
      environment = "test"
    }
    services = [
      "stackdriver.googleapis.com"
    ]
  }
  # always use this contacts and prefix, regardless of what is in the yaml file
  data_overrides = {
    contacts = {
      "[email protected]" = ["ALL"]
    }
    prefix = "test-pf"
  }
  # location where the yaml files are read from
  factories_config = {
    budgets = {
      billing_account   = var.billing_account_id
      budgets_data_path = "data/budgets"
      notification_channels = {
        billing-default = {
          project_id = "foo-billing-audit"
          type       = "email"
          labels = {
            email_address = "[email protected]"
          }
        }
      }
    }
    folders_data_path  = "data/hierarchy"
    projects_data_path = "data/projects"
    context = {
      folder_ids = {
        default = "folders/5678901234"
        teams   = "folders/5678901234"
      }
      iam_principals = {
        gcp-devops = "group:[email protected]"
      }
      tag_values = {
        "org-policies/drs-allow-all" = "tagValues/123456"
      }
      vpc_host_projects = {
        dev-spoke-0 = "test-pf-dev-net-spoke-0"
      }
    }
  }
}
# tftest files=0,1,2,3,4,5,6,7,8,9 inventory=example.yaml

A simple hierarchy of folders:

name: Team A
# implicit parent definition via 'default' key
iam:
  roles/viewer:
    - group:[email protected]
    - gcp-devops
# tftest-file id=0 path=data/hierarchy/team-a/_config.yaml schema=folder.schema.json
name: Team B
# explicit parent definition via key
parent: teams
# tftest-file id=1 path=data/hierarchy/team-b/_config.yaml schema=folder.schema.json
name: Team C
# explicit parent definition via folder id
parent: folders/5678901234
# tftest-file id=2 path=data/hierarchy/team-c/_config.yaml schema=folder.schema.json
name: App 0
# tftest-file id=3 path=data/hierarchy/team-a/app-0/_config.yaml schema=folder.schema.json
name: App 0
tag_bindings:
  drs-allow-all: org-policies/drs-allow-all
# tftest-file id=4 path=data/hierarchy/team-b/app-0/_config.yaml schema=folder.schema.json

One project defined within the folder hierarchy:

billing_account: 012345-67890A-BCDEF0
services:
  - container.googleapis.com
  - storage.googleapis.com
# tftest-file id=5 path=data/hierarchy/teams-iac-0.yaml schema=project.schema.json

More traditional project definitions via the project factory data:

billing_account: 012345-67890A-BCDEF0
labels:
 app: app-0
 team: team-a
parent: team-a/app-0
service_encryption_key_ids:
 storage.googleapis.com:
  - projects/kms-central-prj/locations/europe-west3/keyRings/my-keyring/cryptoKeys/europe3-gce
services:
  - container.googleapis.com
  - storage.googleapis.com
service_accounts:
  app-0-be:
    display_name: "Backend instances."
    iam_project_roles:
      dev-spoke-0:
        - roles/compute.networkUser
    iam_self_roles:
      - roles/logging.logWriter
      - roles/monitoring.metricWriter
  app-0-fe:
    display_name: "Frontend instances."
    iam_project_roles:
      dev-spoke-0:
        - roles/compute.networkUser
    iam_self_roles:
      - roles/logging.logWriter
      - roles/monitoring.metricWriter
shared_vpc_service_config:
  host_project: dev-spoke-0
  network_users:
    - gcp-devops
  service_agent_iam:
    "roles/container.hostServiceAgentUser":
      - container-engine
    "roles/compute.networkUser":
      - container-engine
billing_budgets:
  - test-100
# tftest-file id=6 path=data/projects/dev-ta-app0-be.yaml schema=project.schema.json

This project defines a controlling project via the automation attributes:

parent: team-b/app-0
services:
- run.googleapis.com
- storage.googleapis.com
iam:
  "roles/owner":
    - rw
  "roles/viewer":
    - ro
shared_vpc_host_config:
  enabled: true
automation:
  project: test-pf-teams-iac-0
  service_accounts:
    rw:
      description: Team B app 0 read/write automation sa.
    ro:
      description: Team B app 0 read-only automation sa.
  bucket:
    description: Team B app 0 Terraform state bucket.
    iam:
      roles/storage.objectCreator:
        - rw
      roles/storage.objectViewer:
        - gcp-devops
        - group:[email protected]
        - rw
        - ro

# tftest-file id=7 path=data/projects/dev-tb-app0-0.yaml schema=project.schema.json

A billing budget:

# billing budget test-100
display_name: 100 dollars in current spend
amount:
  units: 100
filter:
  period:
    calendar: MONTH
  resource_ancestors:
  - folders/1234567890
threshold_rules:
- percent: 0.5
- percent: 0.75
update_rules:
  default:
    disable_default_iam_recipients: true
    monitoring_notification_channels:
    - billing-default
# tftest-file id=8 path=data/budgets/test-100.yaml schema=budget.schema.json

Granting permissions to service accounts defined in other project through interpolation:

billing_account: 012345-67890A-BCDEF0
labels:
 app: app-0
 team: team-b
parent: team-b/app-0
services:
  - container.googleapis.com
  - storage.googleapis.com
iam:
  "roles/run.admin":
    - dev-ta-app0-be/app-0-be # interpolate to app-0-be service account in project defined in file dev-ta-app0-be
  "roles/run.developer":
    - app-0-be # interpolate to app-0-be service account within the same project
service_accounts:
  app-0-be:
    display_name: "Backend instances."
    iam_self_roles:
      - roles/logging.logWriter
      - roles/monitoring.metricWriter
# tftest-file id=9 path=data/projects/dev-tb-app0-1.yaml schema=project.schema.json

Files

name description modules
automation.tf Automation projects locals and resources. gcs · iam-service-account
factory-budgets.tf Billing budget factory locals.
factory-folders.tf Folder hierarchy factory locals.
factory-projects-object.tf None
factory-projects.tf Projects factory locals.
folders.tf Folder hierarchy factory resources. folder
main.tf Projects and billing budgets factory resources. billing-account · gcs · iam-service-account · project
outputs.tf Module outputs.
variables.tf Module variables.

Variables

name description type required default
factories_config Path to folder with YAML resource description data files. object({…}) ✓
data_defaults Optional default values used when corresponding project data from files are missing. object({…}) {}
data_merges Optional values that will be merged with corresponding data from files. Combines with data_defaults, file data, and data_overrides. object({…}) {}
data_overrides Optional values that override corresponding data from files. Takes precedence over file data and data_defaults. object({…}) {}

Outputs

name description sensitive
buckets Bucket names.
folders Folder ids.
projects Created projects.
service_accounts Service account emails.

Tests

These tests validate fixes to the project factory.

module "project-factory" {
  source = "./fabric/modules/project-factory"
  data_defaults = {
    billing_account = "012345-67890A-ABCDEF"
  }
  data_merges = {
    labels = {
      owner = "foo"
    }
    services = [
      "compute.googleapis.com"
    ]
  }
  data_overrides = {
    prefix = "foo"
  }
  factories_config = {
    projects_data_path = "data/projects"
  }
}
# tftest modules=4 resources=22 files=test-0,test-1,test-2
parent: folders/1234567890
services:
  - iam.googleapis.com
  - contactcenteraiplatform.googleapis.com
  - container.googleapis.com
# tftest-file id=test-0 path=data/projects/test-0.yaml
parent: folders/1234567890
services:
  - iam.googleapis.com
  - contactcenteraiplatform.googleapis.com
# tftest-file id=test-1 path=data/projects/test-1.yaml
parent: folders/1234567890
services:
  - iam.googleapis.com
  - storage.googleapis.com
# tftest-file id=test-2 path=data/projects/test-2.yaml