Managing Connections

Airflow needs to know how to connect to your environment. Information such as hostname, port, login and passwords to other systems and services is handled in the Admin->Connections section of the UI. The pipeline code you will author will reference the ‘conn_id’ of the Connection objects.

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Connections can be created and managed using either the UI or environment variables.

See the Connenctions Concepts documentation for more information.

Creating a Connection with the UI

Open the Admin->Connections section of the UI. Click the Create link to create a new connection.

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  1. Fill in the Conn Id field with the desired connection ID. It is recommended that you use lower-case characters and separate words with underscores.
  2. Choose the connection type with the Conn Type field.
  3. Fill in the remaining fields. See Connection Types for a description of the fields belonging to the different connection types.
  4. Click the Save button to create the connection.

Editing a Connection with the UI

Open the Admin->Connections section of the UI. Click the pencil icon next to the connection you wish to edit in the connection list.

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Modify the connection properties and click the Save button to save your changes.

Creating a Connection with Environment Variables

Connections in Airflow pipelines can be created using environment variables. The environment variable needs to have a prefix of AIRFLOW_CONN_ for Airflow with the value in a URI format to use the connection properly.

When referencing the connection in the Airflow pipeline, the conn_id should be the name of the variable without the prefix. For example, if the conn_id is named postgres_master the environment variable should be named AIRFLOW_CONN_POSTGRES_MASTER (note that the environment variable must be all uppercase). Airflow assumes the value returned from the environment variable to be in a URI format (e.g. postgres://user:password@localhost:5432/master or s3://accesskey:secretkey@S3).

Connection Types

Google Cloud Platform

The Google Cloud Platform connection type enables the GCP Integrations.

Authenticating to GCP

There are two ways to connect to GCP using Airflow.

  1. Use Application Default Credentials, such as via the metadata server when running on Google Compute Engine.
  2. Use a service account key file (JSON format) on disk.

Default Connection IDs

The following connection IDs are used by default.

bigquery_default
Used by the BigQueryHook hook.
google_cloud_datastore_default
Used by the DatastoreHook hook.
google_cloud_default
Used by the GoogleCloudBaseHook, DataFlowHook, DataProcHook, MLEngineHook, and GoogleCloudStorageHook hooks.

Configuring the Connection

Project Id (required)
The Google Cloud project ID to connect to.
Keyfile Path

Path to a service account key file (JSON format) on disk.

Not required if using application default credentials.

Keyfile JSON

Contents of a service account key file (JSON format) on disk. It is recommended to Secure your connections if using this method to authenticate.

Not required if using application default credentials.

Scopes (comma separated)

A list of comma-separated Google Cloud scopes to authenticate with.

Note

Scopes are ignored when using application default credentials. See issue AIRFLOW-2522.

MySQL

The MySQL connection type provides connection to a MySQL database.

Configuring the Connection

Host (required)
The host to connect to.
Schema (optional)
Specify the schema name to be used in the database.
Login (required)
Specify the user name to connect.
Password (required)
Specify the password to connect.
Extra (optional)

Specify the extra parameters (as json dictionary) that can be used in mysql connection. The following parameters are supported:

  • charset: specify charset of the connection
  • cursor: one of “sscursor”, “dictcursor, “ssdictcursor” - specifies cursor class to be used
  • local_infile: controls MySQL’s LOCAL capability (permitting local data loading by clients). See MySQLdb docs for details.
  • unix_socket: UNIX socket used instead of the default socket
  • ssl: Dictionary of SSL parameters that control connecting using SSL (those parameters are server specific and should contain “ca”, “cert”, “key”, “capath”, “cipher” parameters. See MySQLdb docs for details. Note that in order to be useful in URL notation, this parameter might also be a string where the SSL dictionary is a string-encoded JSON dictionary.

Example “extras” field:

{
   "charset": "utf8",
   "cursorclass": "sscursor",
   "local_infile": true,
   "unix_socket": "/var/socket",
   "ssl": {
     "cert": "/tmp/client-cert.pem",
     "ca": "/tmp/server-ca.pem'",
     "key": "/tmp/client-key.pem"
   }
}

or

{
   "charset": "utf8",
   "cursorclass": "sscursor",
   "local_infile": true,
   "unix_socket": "/var/socket",
   "ssl": "{\"cert\": \"/tmp/client-cert.pem\", \"ca\": \"/tmp/server-ca.pem\", \"key\": \"/tmp/client-key.pem\"}"
}

When specifying the connection as URI (in AIRFLOW_CONN_* variable) you should specify it following the standard syntax of DB connections, where extras as passed as parameters of the URI (note that all components of the URI should be URL-encoded).

For example:

mysql://mysql_user:XXXXXXXXXXXX@1.1.1.1:3306/mysqldb?ssl=%7B%22cert%22%3A+%22%2Ftmp%2Fclient-cert.pem%22%2C+%22ca%22%3A+%22%2Ftmp%2Fserver-ca.pem%22%2C+%22key%22%3A+%22%2Ftmp%2Fclient-key.pem%22%7D

Note

If encounter UnicodeDecodeError while working with MySQL connection check the charset defined is matched to the database charset.

Postgres

The Postgres connection type provides connection to a Postgres database.

Configuring the Connection

Host (required)
The host to connect to.
Schema (optional)
Specify the schema name to be used in the database.
Login (required)
Specify the user name to connect.
Password (required)
Specify the password to connect.
Extra (optional)

Specify the extra parameters (as json dictionary) that can be used in mysql connection. The following parameters out of the standard python parameters are supported:

  • sslmode - This option determines whether or with what priority a secure SSL TCP/IP connection will be negotiated with the server. There are six modes: ‘disable’, ‘allow’, ‘prefer’, ‘require’, ‘verify-ca’, ‘verify-full’.
  • sslcert - This parameter specifies the file name of the client SSL certificate, replacing the default.
  • sslkey - This parameter specifies the file name of the client SSL key, replacing the default.
  • sslrootcert - This parameter specifies the name of a file containing SSL certificate authority (CA) certificate(s).
  • sslcrl - This parameter specifies the file name of the SSL certificate revocation list (CRL).
  • application_name - Specifies a value for the application_name configuration parameter.
  • keepalives_idle - Controls the number of seconds of inactivity after which TCP should send a keepalive message to the server.

More details on all Postgres parameters supported can be found in Postgres documentation

Example “extras” field:

{
   "sslmode": "verify-ca",
   "sslcert": "/tmp/client-cert.pem",
   "sslca": "/tmp/server-ca.pem'",
   "sslkey": "/tmp/client-key.pem"
}

When specifying the connection as URI (in AIRFLOW_CONN_* variable) you should specify it following the standard syntax of DB connections, where extras as passed as parameters of the URI (note that all components of the URI should be URL-encoded).

For example:

postgresql://postgres_user:XXXXXXXXXXXX@1.1.1.1:5432/postgresdb?sslmode=verify-ca&sslcert=%2Ftmp%2Fclient-cert.pem&sslkey=%2Ftmp%2Fclient-key.pem&sslrootcert=%2Ftmp%2Fserver-ca.pem

Cloudsql

The gcpcloudsql:// connection is used by airflow.contrib.operators.gcp_sql_operator.CloudSqlQueryOperator to perform query on a Google Cloud SQL database. Google Cloud SQL database can be either Postgres or MySQL, so this is a “meta” connection type - it introduces common schema for both MySQL and Postgres, including what kind of connectivity should be used. Google Cloud SQL supports connecting via public IP or via Cloud Sql Proxy and in the latter case the CloudSqlDatabaseHook uses CloudSqlProxyRunner to automatically prepare and use temporary Postgres or MySQL connection that will use the proxy to connect (either via TCP or UNIX socket)

Configuring the Connection

Host (required)
The host to connect to.
Schema (optional)
Specify the schema name to be used in the database.
Login (required)
Specify the user name to connect.
Password (required)
Specify the password to connect.
Extra (optional)

Specify the extra parameters (as json dictionary) that can be used in mysql connection.

Details of all the parameters supported in extra field can be found in CloudSqlDatabaseHook

Example “extras” field:

{
   "database_type": "mysql",
   "project_id": "example-project",
   "location": "europe-west1",
   "instance": "testinstance",
   "use_proxy": true,
   "sql_proxy_use_tcp": false
}

When specifying the connection as URI (in AIRFLOW_CONN_* variable) you should specify it following the standard syntax of DB connections, where extras as passed as parameters of the URI (note that all components of the URI should be URL-encoded).

For example:

gcpcloudsql://user:XXXXXXXXX@1.1.1.1:3306/mydb?database_type=mysql&project_id=example-project&location=europe-west1&instance=testinstance&use_proxy=True&sql_proxy_use_tcp=False