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This page explains how to set environment variables in your Cloud Composer environment.
You can use environment variables as an alternative to Airflow variables when providing runtime configuration for your DAGs. Airflow variables are set in the Airflow database, while environment variables are set in the Airflow worker's container.
As an example, you can use an environment variable's name as is in a command
that is run by a BashOperator, or get this value from the os.environ object
in the DAG, or use an Airflow variable instead.
Environment variables are persistent. Once you specify an environment variable, Airflow keeps using it until you remove the variable from your environment.
Cloud Composer sets its own reserved environment variables for controlling environments.
Name format
Environment variables must match the regular expression
[a-zA-Z_][a-zA-Z0-9_]*.
Airflow configuration options
It is not possible to specify variables that change Apache Airflow configuration options.
The variables cannot use the AIRFLOW__{SECTION}__{KEY} format or match the
regular expression AIRFLOW__[A-Z0-9_]+__[A-Z0-9_]+. For example, it is not
possible to set AIRFLOW__WEBSERVER__DAG_DEFAULT_VIEW.
Instead, you can override Airflow configuration options.
Reserved variables
The following variable names are reserved by Cloud Composer. It is not possible to create variables with these names.
AIRFLOW_DATABASE_VERSIONAIRFLOW_HOMEAIRFLOW_SRC_DIRAIRFLOW_WEBSERVERAUTO_GKECLOUDSDK_METRICS_ENVIRONMENTCLOUD_LOGGING_ONLYCOMPOSER_AGENT_BUILD_SERVICE_ACCOUNTCOMPOSER_ENVIRONMENTCOMPOSER_GKE_LOCATIONCOMPOSER_GKE_NAMECOMPOSER_GKE_ZONECOMPOSER_LOCATIONCOMPOSER_OPERATION_UUIDCOMPOSER_PYTHON_VERSIONCOMPOSER_VERSIONCONTAINER_NAMEC_FORCE_ROOTDAGS_FOLDERGCP_PROJECTGCP_TENANT_PROJECTGCSFUSE_EXTRACTEDGCS_BUCKETGKE_CLUSTER_NAMEGKE_IN_TENANTGOOGLE_APPLICATION_CREDENTIALSMAJOR_VERSIONMINOR_VERSIONPATHPIP_DISABLE_PIP_VERSION_CHECKPORTPROJECT_IDPYTHONPYCACHEPREFIXPYTHONWARNINGSREDIS_PASSWORDREDIS_PORTREDIS_USERSQL_DATABASESQL_HOSTSQL_INSTANCESQL_PASSWORDSQL_PROJECTSQL_REGIONSQL_USER
Set environment variables for new environments
You can specify environment variables when you create an environment. For more information, see Create environments.
Set environment variables for existing environments
Console
To set environment variables for an existing environment:
In Google Cloud console, go to the Environments page.
In the list of environments, click the name of your environment. The Environment details page opens.
Go to the Environment variables tab and click Edit.
Add, change, or delete environment variables for your environment:
- In the Name field, specify the variable name.
- In the Value field, specify the variable value.
- To add an extra variable, click Add environment variable.
- To delete a variable, hold the pointer over a variable, then click Delete item.
gcloud
Following arguments control environment variables:
--update-env-variablesspecifies a comma-separated list of environment variables to create or update.--remove-env-variablesspecifies a comma-separated list of environment variables to delete.--clear-env-variablesdeletes all existing environment variables.
gcloud composer environments update \
ENVIRONMENT_NAME \
--location LOCATION \
--update-env-variables=NAME=VALUE
Replace:
ENVIRONMENT_NAMEwith the name of the environment.LOCATIONwith the region where the environment is located.NAMEwith the name of the variable that you want to create or update.VALUEwith the value for the variable.- To add more than one variable, separate the definitions with commas:
NAME=VALUE,NAME=VALUE,....
Example:
gcloud composer environments update \
example-environment \
--location us-central1 \
--update-env-variables=EXAMPLE_VARIABLE=True,ANOTHER_VARIABLE=test
API
Construct an environments.patch API request.
In this request:
In the
updateMaskparameter, specify theconfig.softwareConfig.envVariablesmask to replace all existing variables with the specified variables. Variables that you don't specify are deleted.In the request body, specify variables and their values:
{ "config": { "softwareConfig": { "envVariables": { "VAR_NAME": "VAR_VALUE" } } } }Replace:
VAR_NAMEwith the name of the environment variable.VAR_VALUEwith the value of the environment variable.- To add more than one variable, add extra entries for variables
to
envVariables.
Example:
// PATCH https://composer.googleapis.com/v1/projects/example-project/
// locations/us-central1/environments/example-environment?updateMask=
// config.softwareConfig.envVariables
{
"config": {
"softwareConfig": {
"envVariables": {
"EXAMPLE_VARIABLE": "True",
"ANOTHER_VARIABLE": "test"
}
}
}
}
Terraform
The env_variables block in the software_config block specifies
environment variables.
resource "google_composer_environment" "example" {
provider = google-beta
name = "ENVIRONMENT_NAME"
region = "LOCATION"
config {
software_config {
env_variables = {
VAR_NAME = "VAR_VALUE"
}
}
}
}
Replace:
ENVIRONMENT_NAMEwith the name of the environment.LOCATIONwith the region where the environment is located.VAR_NAMEwith the name of the environment variable.VAR_VALUEwith the value of the environment variable.- To add more than one variable, add extra entries for variables
to
env_variables.
Example:
resource "google_composer_environment" "example" {
provider = google-beta
name = "example-environment"
region = "us-central1"
config {
software_config {
env_variables = {
EXAMPLE_VARIABLE = "True"
ANOTHER_VARIABLE = "test"
}
}
}
}