meltanolabs-target-postgres 0.0.4

`target-postgres` is a Singer target for Postgres, built with the Meltano SDK for Singer Targets.

target-postgres

Target for Postgres.

Built with the Meltano SDK for Singer Taps and Targets. This target is in development, it probably doesn't work yet, stick with https://hub.meltano.com/loaders/target-postgres . Generally the goal here is to create a generalized target enough so that the SDK can automate >80% of testing for new targets, and potentially so taps can test very easily with a real local target.

Limitations

1. Target is not working with Empty key properties. See https://github.com/MeltanoLabs/target-postgres/issues/54

Capabilities

• about
• stream-maps
• schema-flattening

Settings

Setting	Required	Default	Description
host	False	None	Hostname for postgres instance. Note if sqlalchemy_url is set this will be ignored.
port	False	5432	The port on which postgres is awaiting connection. Note if sqlalchemy_url is set this will be ignored.
user	False	None	User name used to authenticate. Note if sqlalchemy_url is set this will be ignored.
password	False	None	Password used to authenticate. Note if sqlalchemy_url is set this will be ignored.
database	False	None	Database name. Note if sqlalchemy_url is set this will be ignored.
sqlalchemy_url	False	None	SQLAlchemy connection string. This will override using host, user, password, port, dialect. Note that you must esacpe password special characters properly see https://docs.sqlalchemy.org/en/20/core/engines.html#escaping-special-characters-such-as-signs-in-passwords
dialect+driver	False	postgresql+psycopg2	Dialect+driver see https://docs.sqlalchemy.org/en/20/core/engines.html. Generally just leave this alone. Note if sqlalchemy_url is set this will be ignored.
stream_maps	False	None	Config object for stream maps capability. For more information check out Stream Maps.
stream_map_config	False	None	User-defined config values to be used within map expressions.
flattening_enabled	False	None	'True' to enable schema flattening and automatically expand nested properties.
flattening_max_depth	False	None	The max depth to flatten schemas.

A full list of supported settings and capabilities is available by running: target-postgres --about

Installation

• Developer TODO: Come back to this re #5

pipx install -e .

Configuration

Configure using environment variables

This Singer target will automatically import any environment variables within the working directory's .env if the --config=ENV is provided, such that config values will be considered if a matching environment variable is set either in the terminal context or in the .env file.

Source Authentication and Authorization

The database account provided must have access to:

1. Create schemas
2. Create tables (DDL)
3. Push Data to tables (DML)

Usage

You can easily run target-postgres by itself or in a pipeline using Meltano.

Executing the Target Directly

target-postgres --version
target-postgres --help
# Test using the "Carbon Intensity" sample:
pipx install git+https://gitlab.com/meltano/tap-carbon-intensity
tap-carbon-intensity | target-postgres --config /path/to/target-postgres-config.json

Developer Resources

Initialize your Development Environment

pipx install poetry
poetry install
pipx install pre-commit
pre-commit install

Create and Run Tests

Create tests within the target_postgres/tests subfolder and then run:

poetry run pytest

You can also test the target-postgres CLI interface directly using poetry run:

poetry run target-postgres --help

Testing with Meltano

Note: This target will work in any Singer environment and does not require Meltano. Examples here are for convenience and to streamline end-to-end orchestration scenarios.

Your project comes with a custom meltano.yml project file already created.

Next, install Meltano (if you haven't already) and any needed plugins:

# Install meltano
pipx install meltano
# Initialize meltano within this directory
meltano install

Now you can test and orchestrate using Meltano:

# Test invocation:
meltano invoke target-postgres --version

SDK Dev Guide

See the dev guide for more instructions on how to use the Meltano SDK to develop your own Singer taps and targets.