Google Cloud Secret Manager Backend

This topic describes how to configure Airflow to use Secret Manager as a secret backend and how to manage secrets.

Before you begin

Before you start, make sure you have performed the following tasks:

  1. Include google subpackage as an extra of your Airflow installation

    pip install apache-airflow[google]

  2. Configure Secret Manager and your local environment, once per project.

Enabling the secret backend

To enable the secret backend for Google Cloud Secrets Manager to retrieve connection/variables, specify CloudSecretManagerBackend as the backend in [secrets] section of airflow.cfg.

Here is a sample configuration if you want to use it:

[secrets]
backend = airflow.providers.google.cloud.secrets.secret_manager.CloudSecretManagerBackend

You can also set this with environment variables.

export AIRFLOW__SECRETS__BACKEND=airflow.providers.google.cloud.secrets.secret_manager.CloudSecretManagerBackend

You can verify the correct setting of the configuration options with the airflow config get-value command.

$ airflow config get-value secrets backend
airflow.providers.google.cloud.secrets.secret_manager.CloudSecretManagerBackend

Backend parameters

The next step is to configure backend parameters using the backend_kwargs options. You can pass the following parameters:

  • connections_prefix: Specifies the prefix of the secret to read to get Connections. Default: "airflow-connections"

  • variables_prefix: Specifies the prefix of the secret to read to get Variables. Default: "airflow-variables"

  • gcp_key_path: Path to Google Cloud Service Account Key file (JSON).

  • gcp_keyfile_dict: Dictionary of keyfile parameters.

  • gcp_scopes: Comma-separated string containing OAuth2 scopes.

  • sep: Separator used to concatenate connections_prefix and conn_id. Default: "-"

  • project_id: Project ID to read the secrets from. If not passed, the project ID from credentials will be used.

All options should be passed as a JSON dictionary.

For example, if you want to set parameter connections_prefix to "example-connections-prefix" and parameter variables_prefix to "example-variables-prefix", your configuration file should look like this:

[secrets]
backend = airflow.providers.google.cloud.secrets.secret_manager.CloudSecretManagerBackend
backend_kwargs = {"connections_prefix": "example-connections-prefix", "variables_prefix": "example-variables-prefix"}

Set-up credentials

You can configure the credentials in three ways:

  • By default, Application Default Credentials (ADC) is used obtain credentials.

  • gcp_key_path option in backend_kwargs option - allows you to configure authorizations with a service account stored in local file.

  • gcp_keyfile_dict option in backend_kwargs option - allows you to configure authorizations with a service account stored in Airflow configuration.

Note

For more information about the Application Default Credentials (ADC), see:

Managing secrets

If you want to configure a connection, you need to save it as a connection URI representation. Variables should be saved as plain text.

In order to manage secrets, you can use the gcloud tool or other supported tools. For more information, take a look at: Managing secrets in Google Cloud Documentation.

The name of the secret must fit the following formats:

  • for connections: [connections_prefix][sep][connection_name]

  • for variables: [variables_prefix][sep][variable_name]

  • for Airflow config: [config_prefix][sep][config_name]

where:

  • connections_prefix - fixed value defined in the connections_prefix parameter in backend configuration. Default: airflow-connections.

  • variables_prefix - fixed value defined in the variables_prefix parameter in backend configuration. Default: airflow-variables.

  • config_prefix - fixed value defined in the config_prefix parameter in backend configuration. Default: airflow-config.

  • sep - fixed value defined in the sep parameter in backend configuration. Default: -.

The Cloud Secrets Manager secret name should follow the pattern ^[a-zA-Z0-9-_]*$.

If you have the default backend configuration and you want to create a connection with conn_id equals first-connection, you should create secret named airflow-connections-first-connection. You can do it with the gcloud tools as in the example below.

$ echo "mysql://example.org" | gcloud beta secrets create \
    airflow-connections-first-connection \
    --data-file=- \
    --replication-policy=automatic
Created version [1] of the secret [airflow-connections-first-connection].

If you have the default backend configuration and you want to create a variable named first-variable, you should create a secret named airflow-variables-first-variable. You can do it with the gcloud command as in the example below.

$ echo "secret_content" | gcloud beta secrets create \
    airflow-variables-first-variable \
    --data-file=-\
    --replication-policy=automatic
Created version [1] of the secret [airflow-variables-first-variable].

Note

If only key of the connection should be hidden there is an option to store only that key in Cloud Secret Manager and not entire connection. For more details take a look at Google Cloud Connection.

Checking configuration

You can use the airflow connections get command to check if the connection is correctly read from the backend secret:

$ airflow connections get first-connection
Id: null
Connection Id: first-connection
Connection Type: mysql
Host: example.org
Schema: ''
Login: null
Password: null
Port: null
Is Encrypted: null
Is Extra Encrypted: null
Extra: {}
URI: mysql://example.org

To check the variables is correctly read from the backend secret, you can use airflow variables get:

$ airflow variables get first-variable
secret_content

Clean up

To avoid incurring charges to your Google Cloud account for the resources used in this guide, delete secrets by running gcloud beta secrets delete:

gcloud beta secrets delete airflow-connections-first-connection
gcloud beta secrets delete airflow-variables-first-variable

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