Environment

Sling looks for connection credentials in several places:

• Sling Env File (located at ~/.sling/env.yaml)

• DBT Profiles Files (located at ~/.dbt/profiles.yml)

• Environment Variables

One of the easiest ways is to manage your connections is to use the sling conns sub-command. Follow in the next section.

Managing Connections

Sling makes it easy to set, list and test connections. You can even see the available streams in a connection by using the discover sub-command.

$ sling conns -h
conns - Manage local connections

See more details at https://docs.slingdata.io/sling-cli/

  Usage:
    conns [discover|list|set|test]

  Subcommands:
    discover   list available streams in connection
    list       list local connections detected
    set        set a connection in the sling env file
    test       test a local connection

  Flags:
       --version   Displays the program version string.
    -h --help      Displays help with available flag, subcommand, and positional value parameters.

Set Connections

Here we can easily set a connection with the sling conns set command and later refer to them by their name. This ensures credentials are not visible by other users when using process monitors, for example.

# set a connection by providing the key=value pairs
$ sling conns set AWS_S3 type=s3 bucket=sling-bucket access_key_id=ACCESS_KEY_ID secret_access_key="SECRET_ACCESS_KEY"

# we set a database connection with just the url
$ sling conns set MY_PG url='postgresql://postgres:myPassword@pghost:5432/postgres'

To see what credential keys are necessary/accepted for each type of connector, click below:

• File/Storage Connections (see here)

• Database Connections (see here)

List Connections

Once connections are set, we can run the sling conns list command to list our detected connections:

$ sling conns list
+--------------------------+-----------------+-------------------+
| CONN NAME                | CONN TYPE       | SOURCE            |
+--------------------------+-----------------+-------------------+
| AWS_S3                   | FileSys - S3    | sling env yaml    |
| FINANCE_BQ               | DB - BigQuery   | sling env yaml    |
| DO_SPACES                | FileSys - S3    | sling env yaml    |
| LOCALHOST_DEV            | DB - PostgreSQL | dbt profiles yaml |
| MSSQL                    | DB - SQLServer  | sling env yaml    |
| MYSQL                    | DB - MySQL      | sling env yaml    |
| ORACLE_DB                | DB - Oracle     | env variable      |
| MY_PG                    | DB - PostgreSQL | sling env yaml    |
+--------------------------+-----------------+-------------------+

Test Connections

We can also test a connection by running the sling conns test command:

$ sling conns test LOCALHOST_DEV
9:04AM INF success!

Discover Connections

We can easily discover streams available in a connection with the sling conns discover command:

$ sling conns discover LOCALHOST_DEV
9:05AM INF Found 344 streams:
 - "public"."accounts"
 - "public"."bills"
 - "public"."connections"
 ...

Credentials Location

Sling Env File (env.yaml)

The Sling Env file is the primary way sling reads connections. It needs to be saved in the path ~/.sling/env.yaml where the ~ denotes the path of the user Home folder, which can have different locations depending on the operating system (see here for Windows, here for Mac and here for Linux). Sling automatically creates the .sling folder in the user home directory, which is typically as shown below:

• Linux: /home/<username>/.sling, or /root/.sling if user is root

• Mac: /Users/<username>/.sling

• Windows: C:\Users\<username>\.sling

Once in the user home directory, setting the Sling Env File (named env.yaml) is easy, and adheres to the structure below. Running sling the first time will auto-create it. You can alternatively provide the environment variable SLING_HOME_DIR.

To see what credential keys are necessary/accepted for each type of connector, click below:

• File/Storage Connections (see here)

• Database Connections (see here)

# Holds all connection credentials for Extraction and Loading
connections:
  marketing_pg:
    url: 'postgres://...' 
    ssh_tunnel: 'ssh://...' # optional
  
  # or dbt profile styled
  marketing_pg:
    type: postgres        
    host: [hostname]      
    user: [username]      
    password: [password]  
    port: [port]          
    dbname: [database name]
    schema: [dbt schema]  
    ssh_tunnel: 'ssh://...' 
  
  finance_bq:
    type: bigquery
    method: service-account
    project: [GCP project id]
    dataset: [the name of your dbt dataset]
    keyfile: [/path/to/bigquery/keyfile.json]

# Global variables for specific settings, available to all connections at runtime (Optional)
variables:
  aws_access_key: '...'
  aws_secret_key: '...'

Environment Variables

Sling also reads environment variables. Simply export a connection URL (or YAML payload) to the current shell environment to use them.

To see examples of setting environment variables for each type of connector, click below:

• File/Storage Connections (see here)

• Database Connections (see here)

Mac / Linux

$ export MY_PG='postgresql://user:[e-mail]:5432/db1'
$ export MY_PG='{type: postgres, host: "pg.host", user: user, database: "db1", password: "mypassw", port: 5432}'

$ export MY_SNOWFLAKE='snowflake://user:[e-mail]/db1'
$ export MY_SNOWFLAKE='{type: snowflake, host: "<host>", user: "<user>", database: "<database>", password: "<password>", role: "<role>"}'

$ export ORACLE_DB='oracle://user:[e-mail]:1521/db1'

$ export BIGQUERY_DB='{type: bigquery, dataset: public, key_file: /path/to/service.json, project: my-google-project}' # yaml or json form is also accepted

$ sling conns list
+---------------+------------------+-----------------+
| CONN NAME     | CONN TYPE        | SOURCE          |
+---------------+------------------+-----------------+
| MY_PG         | DB - PostgreSQL  | env variable    |
| MY_SNOWFLAKE  | DB - Snowflake   | env variable    |
| ORACLE_DB     | DB - Oracle      | env variable    |
| BIGQUERY_DB   | DB - Big Query   | env variable    |
+---------------+------------------+-----------------+

Windows

$ $env:MY_PG='postgresql://user:[e-mail]:5432/db1'
$ $env:MY_PG='{type: postgres, host: "pg.host", user: user, database: "db1", password: "mypassw", port: 5432}'

$ $env:MY_SNOWFLAKE='snowflake://user:[e-mail]/db1'
$ $env:MY_SNOWFLAKE='{type: snowflake, host: "sf.host", user: user, database: db1, password: "mypassw", role: "<role>"}'

$ $env:ORACLE_DB='oracle://user:[e-mail]:1521/db1'

$ $env:BIGQUERY_DB='{type: bigquery, dataset: public, key_file: /path/to/service.json, project: my-google-project}' # yaml or json form is also accepted

$ sling conns list
+---------------+------------------+-----------------+
| CONN NAME     | CONN TYPE        | SOURCE          |
+---------------+------------------+-----------------+
| MY_PG         | DB - PostgreSQL  | env variable    |
| MY_SNOWFLAKE  | DB - Snowflake   | env variable    |
| ORACLE_DB     | DB - Oracle      | env variable    |
+---------------+------------------+-----------------+

DBT Profiles (~/dbt/profiles.yml)

Sling also reads dbt profiles connections! If you're already set up with dbt cli locally, you don't need to create additional duplicate connections.

See here for more details.

$ sling conns list
+------------------+------------------+-------------------+
| CONN NAME        | CONN TYPE        | SOURCE            |
+------------------+------------------+-------------------+
| SNOWCASTLE_DEV   | DB - Snowflake   | dbt profiles yaml |
| SNOWCASTLE_PROD  | DB - Snowflake   | dbt profiles yaml |
+------------------+------------------+-------------------+