What is packages.yml in dbt: Purpose and Usage Explained

In dbt, packages.yml is a configuration file used to list external dbt packages your project depends on. It helps you easily install and manage shared models, macros, and analyses from other dbt projects.

How It Works

The packages.yml file in dbt acts like a shopping list for your project’s external tools and resources. Imagine you are cooking and need specific ingredients from a store. Instead of searching for each ingredient separately, you write them down on a list. Similarly, packages.yml lists the external dbt packages your project needs.

When you run dbt deps, dbt reads this file and downloads the listed packages into your project. These packages can include pre-built models, macros, or tests created by the community or your team. This way, you can reuse code without rewriting it, saving time and reducing errors.

Example

This example shows a simple packages.yml file that includes two packages: one from the dbt Hub and one from a GitHub repository.

yaml

packages:
  - package: dbt-labs/dbt_utils
    version: 0.8.6
  - git: "https://github.com/fishtown-analytics/dbt-expectations.git"
    revision: 0.4.0

Output

When you run 'dbt deps', dbt downloads these packages into the 'dbt_modules' folder, making their models and macros available in your project.

When to Use

Use packages.yml when you want to include reusable dbt code from other projects. For example, if your team uses common macros for data quality checks, you can add them as a package instead of copying code manually.

It is also helpful when you want to use popular community packages like dbt_utils that provide useful macros and helpers. This keeps your project clean and up to date with improvements from the package maintainers.

Key Points

• Central list: packages.yml lists all external dbt packages your project needs.
• Easy installation: Running dbt deps installs these packages automatically.
• Code reuse: Enables sharing and reusing models, macros, and tests.
• Version control: You can specify exact versions or Git revisions for stability.

Key Takeaways

packages.yml manages external dbt package dependencies for your project.

Running dbt deps installs packages listed in packages.yml.

Use it to reuse community or team-shared dbt code easily.

Specify package versions or Git revisions to control updates.

It helps keep your project modular, clean, and maintainable.