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Using Cloud Storage for TechDocs generated files

In the TechDocs architecture you have the option to choose where you want to store the Generated static files which TechDocs uses to render documentation. In both the "Basic" and "Recommended" setup, you can add cloud storage providers like Google GCS, Amazon AWS S3, etc. By default, TechDocs uses the local filesystem of the techdocs-backend plugin in the "Basic" setup. And in the recommended setup, having one of the cloud storage is a prerequisite. Read more on the TechDocs Architecture documentation page.

On this page you can read how to enable them.

Configuring Google GCS Bucket with TechDocs

Follow the official Google Cloud documentation for the latest instructions on the following steps involving GCP.

1. Set techdocs.publisher.type config in your app-config.yaml

Set techdocs.publisher.type to 'googleGcs'.

techdocs:
  publisher:
    type: 'googleGcs'

2. Create a GCS Bucket

Create a dedicated Google Cloud Storage bucket for TechDocs sites. techdocs-backend will publish documentation to this bucket. TechDocs will fetch files from here to serve documentation in Backstage. Note that the bucket names are globally unique.

Set the config techdocs.publisher.googleGcs.bucketName in your app-config.yaml to the name of the bucket you just created.

techdocs:
  publisher:
    type: 'googleGcs'
    googleGcs:
      bucketName: 'name-of-techdocs-storage-bucket'

3a. (Recommended) Authentication using environment variable

The GCS Node.js client will automatically use the environment variable GOOGLE_APPLICATION_CREDENTIALS to authenticate with Google Cloud. It might already be set in Compute Engine, Google Kubernetes Engine, etc. Read https://cloud.google.com/docs/authentication/production for more details.

3b. Authentication using app-config.yaml

If you do not prefer (3a) and optionally like to use a service account, you can follow these steps.

Create a new Service Account and a key associated with it. In roles of the service account, use "Storage Object Admin".

If you want to create a custom role, make sure to include both get and create permissions for both "Objects" and "Buckets". See https://cloud.google.com/storage/docs/access-control/iam-permissions

A service account can have many keys. Open your newly created account's page (in IAM & Admin console), and create a new key. Use JSON format for the key.

A <GCP-PROJECT-ID-random-uid>.json file will be downloaded. This is the secret key TechDocs will use to make API calls. Make it available in your Backstage server and/or your local development server and set it in the app config techdocs.publisher.googleGcs.credentials.

techdocs:
  publisher:
    type: 'googleGcs'
    googleGcs:
      bucketName: 'name-of-techdocs-storage-bucket'
      credentials:
        $file: '/path/to/google_application_credentials.json'

Note: If you are finding it difficult to make the file google_application_credentials.json available on a server, you could use the file's content and set as an environment variable. And then use

techdocs:
  publisher:
    type: 'googleGcs'
    googleGcs:
      bucketName: 'name-of-techdocs-storage-bucket'
      credentials: ${GOOGLE_APPLICATION_CREDENTIALS}

4. That's it!

Your Backstage app is now ready to use Google Cloud Storage for TechDocs, to store and read the static generated documentation files.

Configuring AWS S3 Bucket with TechDocs

1. Set techdocs.publisher.type config in your app-config.yaml

Set techdocs.publisher.type to 'awsS3'.

techdocs:
  publisher:
    type: 'awsS3'

2. Create an S3 Bucket

Create a dedicated AWS S3 bucket for the storage of TechDocs sites. Refer to the official documentation. Terraform example.

TechDocs will publish documentation to this bucket and will fetch files from here to serve documentation in Backstage. Note that the bucket names are globally unique.

Set the config techdocs.publisher.awsS3.bucketName in your app-config.yaml to the name of the bucket you just created.

techdocs:
  publisher:
    type: 'awsS3'
    awsS3:
      bucketName: 'name-of-techdocs-storage-bucket'

3. Create minimal AWS IAM policies to manage TechDocs

To write TechDocs into the S3 bucket the IAM policy needs to have at a minimum permissions to:

  • s3:ListBucket to retrieve bucket metadata
  • s3:PutObject to upload files to the bucket
  • s3:DeleteObject and s3:DeleteObjectVersion to delete stale content during re-publishing

To read TechDocs from the S3 bucket the IAM policy needs to have at a minimum permissions to:

  • s3:ListBucket - To retrieve bucket metadata
  • s3:GetObject - To retrieve files from the bucket

Note: If you need to migrate documentation objects from an older-style path format including case-sensitive entity metadata, you will need to add some additional permissions to be able to perform the migration, including:

  • s3:PutBucketAcl (for copying files, more info here)
  • s3:DeleteObject and s3:DeleteObjectVersion (for deleting migrated files, more info here)

...And you will need to ensure the permissions apply to the bucket itself, as well as all resources under the bucket. See the example policy below.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "TechDocsWithMigration",
      "Effect": "Allow",
      "Action": [
        "s3:PutObject",
        "s3:GetObject",
        "s3:DeleteObjectVersion",
        "s3:ListBucket",
        "s3:DeleteObject",
        "s3:PutObjectAcl"
      ],
      "Resource": ["arn:aws:s3:::your-bucket", "arn:aws:s3:::your-bucket/*"]
    }
  ]
}

4a. (Recommended) Setup authentication the AWS way, using environment variables

You should follow the AWS security best practices guide for authentication.

TechDocs needs access to read files and metadata of the S3 bucket. So if you are creating a policy for a user you want to make sure it is granted access to ListBucket, GetObject and PutObject.

If the environment variables

  • AWS_ACCESS_KEY_ID
  • AWS_SECRET_ACCESS_KEY
  • AWS_REGION

are set and can be used to access the bucket you created in step 2, they will be used by the AWS SDK V2 Node.js client for authentication. Refer to the official documentation for loading credentials in Node.js from environment variables.

If the environment variables are missing, the AWS SDK tries to read the ~/.aws/credentials file for credentials. Refer to the official documentation.

If you are using Amazon EC2 instance to deploy Backstage, you do not need to obtain the access keys separately. They can be made available in the environment automatically by defining appropriate IAM role with access to the bucket. Read more in official AWS documentation for using IAM roles..

The AWS Region of the bucket is optional since TechDocs uses AWS SDK V2 and not V3.

4b. Authentication using app-config.yaml

AWS credentials and region can be provided to the AWS SDK via app-config.yaml. If the configs below are present, they will be used over existing AWS_* environment variables and the ~/.aws/credentials config file.

techdocs:
  publisher:
    type: 'awsS3'
    awsS3:
      bucketName: 'name-of-techdocs-storage-bucket'
      region: ${AWS_REGION}
      credentials:
        accessKeyId: ${AWS_ACCESS_KEY_ID}
        secretAccessKey: ${AWS_SECRET_ACCESS_KEY}

Refer to the official AWS documentation for obtaining the credentials.

4c. Authentication using an assumed role Users with multiple AWS accounts may want to use a role for S3 storage that is in a different AWS account. Using the roleArn parameter as seen below, you can instruct the TechDocs publisher to assume a role before accessing S3.

techdocs:
  publisher:
    type: 'awsS3'
    awsS3:
      bucketName: 'name-of-techdocs-storage-bucket'
      region: ${AWS_REGION}
      credentials:
        roleArn: arn:aws:iam::123456789012:role/my-backstage-role

Note: Assuming a role requires that primary credentials are already configured at AWS.config.credentials. Read more about assuming roles in AWS.

5. That's it!

Your Backstage app is now ready to use AWS S3 for TechDocs, to store and read the static generated documentation files. When you start the backend of the app, you should be able to see techdocs info Successfully connected to the AWS S3 bucket in the logs.

Configuring Azure Blob Storage Container with TechDocs

Follow the official Azure Blob Storage documentation for the latest instructions on the following steps involving Azure Blob Storage.

1. Set techdocs.publisher.type config in your app-config.yaml

Set techdocs.publisher.type to 'azureBlobStorage'.

techdocs:
  publisher:
    type: 'azureBlobStorage'

2. Create an Azure Blob Storage Container

Create a dedicated container for TechDocs sites. Refer to the official documentation.

TechDocs will publish documentation to this container and will fetch files from here to serve documentation in Backstage. Note that the container names are globally unique.

Set the config techdocs.publisher.azureBlobStorage.containerName in your app-config.yaml to the name of the container you just created.

techdocs:
  publisher:
    type: 'azureBlobStorage'
    azureBlobStorage:
      containerName: 'name-of-techdocs-storage-container'

3a. (Recommended) Authentication using environment variable

If you do not prefer (3a) and optionally like to use a service account, you can set the config techdocs.publisher.azureBlobStorage.credentials.accountName in your app-config.yaml to the your account name.

The storage blob client will automatically use the environment variable AZURE_TENANT_ID, AZURE_CLIENT_ID, AZURE_CLIENT_SECRET to authenticate with Azure Blob Storage. Steps to create the service where the variables can be retrieved from.

https://docs.microsoft.com/en-us/azure/storage/common/storage-auth-aad for more details.

techdocs:
  publisher:
    type: 'azureBlobStorage'
    azureBlobStorage:
      containerName: 'name-of-techdocs-storage-bucket'
      credentials:
        accountName: ${TECHDOCS_AZURE_BLOB_STORAGE_ACCOUNT_NAME}

3b. Authentication using app-config.yaml

If you do not prefer (3a) and optionally like to use a service account, you can follow these steps.

To get credentials, access the Azure Portal and go to "Settings > Access Keys", and get your Storage account name and Primary Key. https://docs.microsoft.com/en-us/rest/api/storageservices/authorize-with-shared-key for more details.

techdocs:
  publisher:
    type: 'azureBlobStorage'
    azureBlobStorage:
      containerName: 'name-of-techdocs-storage-bucket'
      credentials:
        accountName: ${TECHDOCS_AZURE_BLOB_STORAGE_ACCOUNT_NAME}
        accountKey: ${TECHDOCS_AZURE_BLOB_STORAGE_ACCOUNT_KEY}

In either case, the account or credentials used to access your container and all TechDocs objects underneath it should have the Storage Blog Data Owner role applied, in order to read, write, and delete objects as needed.

4. That's it!

Your Backstage app is now ready to use Azure Blob Storage for TechDocs, to store and read the static generated documentation files. When you start the backend of the app, you should be able to see techdocs info Successfully connected to the Azure Blob Storage container in the logs.

Configuring OpenStack Swift Container with TechDocs

Follow the official OpenStack Api documentation for the latest instructions on the following steps involving OpenStack Storage.

1. Set techdocs.publisher.type config in your app-config.yaml

Set techdocs.publisher.type to 'openStackSwift'.

techdocs:
  publisher:
    type: 'openStackSwift'

2. Create an OpenStack Swift Storage Container

Create a dedicated container for TechDocs sites. Refer to the official documentation.

TechDocs will publish documentation to this container and will fetch files from here to serve documentation in Backstage. Note that the container names are globally unique.

Set the config techdocs.publisher.openStackSwift.containerName in your app-config.yaml to the name of the container you just created.

techdocs:
  publisher:
    type: 'openStackSwift'
    openStackSwift:
      containerName: 'name-of-techdocs-storage-container'

3. Authentication using app-config.yaml

Set the configs in your app-config.yaml to point to your container name.

https://docs.openstack.org/api-ref/identity/v3/?expanded=password-authentication-with-unscoped-authorization-detail,authenticating-with-an-application-credential-detail#authenticating-with-an-application-credential for more details.

techdocs:
  publisher:
    type: 'openStackSwift'
    openStackSwift:
      containerName: 'name-of-techdocs-storage-bucket'
      credentials:
        id: ${OPENSTACK_SWIFT_STORAGE_APPLICATION_CREDENTIALS_ID}
        secret: ${OPENSTACK_SWIFT_STORAGE_APPLICATION_CREDENTIALS_SECRET}
      authUrl: ${OPENSTACK_SWIFT_STORAGE_AUTH_URL}
      swiftUrl: ${OPENSTACK_SWIFT_STORAGE_SWIFT_URL}

4. That's it!

Your Backstage app is now ready to use OpenStack Swift Storage for TechDocs, to store and read the static generated documentation files. When you start the backend of the app, you should be able to see techdocs info Successfully connected to the OpenStack Swift Storage container in the logs.

Bonus: Migration from old OpenStack Swift Configuration

Let's assume we have the old OpenStack Swift configuration here.

techdocs:
  publisher:
    type: 'openStackSwift'
    openStackSwift:
      containerName: 'name-of-techdocs-storage-bucket'
      credentials:
        username: ${OPENSTACK_SWIFT_STORAGE_USERNAME}
        password: ${OPENSTACK_SWIFT_STORAGE_PASSWORD}
      authUrl: ${OPENSTACK_SWIFT_STORAGE_AUTH_URL}
      keystoneAuthVersion: ${OPENSTACK_SWIFT_STORAGE_AUTH_VERSION}
      domainId: ${OPENSTACK_SWIFT_STORAGE_DOMAIN_ID}
      domainName: ${OPENSTACK_SWIFT_STORAGE_DOMAIN_NAME}
      region: ${OPENSTACK_SWIFT_STORAGE_REGION}
Step 1: Change the credential keys

Since the new SDK uses Application Credentials to authenticate OpenStack, we need to change the keys credentials.username to credentials.id, credentials.password to credentials.secret and use Application Credential ID and secret here. For more detail about credentials look here.

Step 2: Remove the unused keys

Since the new SDK doesn't use the old way authentication, we don't need the keys openStackSwift.keystoneAuthVersion, openStackSwift.domainId, openStackSwift.domainName and openStackSwift.region. So you can remove them.

Step 3: Add Swift URL

The new SDK needs the OpenStack Swift connection URL for connecting the Swift. So you need to add a new key called openStackSwift.swiftUrl and give the OpenStack Swift url here. Example url should look like that: https://example.com:6780/swift/v1

That's it!

Your new configuration should look like that!

techdocs:
  publisher:
    type: 'openStackSwift'
    openStackSwift:
      containerName: 'name-of-techdocs-storage-bucket'
      credentials:
        id: ${OPENSTACK_SWIFT_STORAGE_APPLICATION_CREDENTIALS_ID}
        secret: ${OPENSTACK_SWIFT_STORAGE_APPLICATION_CREDENTIALS_SECRET}
      authUrl: ${OPENSTACK_SWIFT_STORAGE_AUTH_URL}
      swiftUrl: ${OPENSTACK_SWIFT_STORAGE_SWIFT_URL}
Last updated on 1/17/2022
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