Pose: a Docker Com-"pose" CLI

Docker compose "helper" to release apps in a transactional manner !

pose is a command line tool to play with 🐳 Docker Compose files.

It allows to list some properties from your compose.yaml file, but more importantly, it does allow in CI environments to tests distributed apps with docker compose, building on the fly a new compose file from another, replacing tag versions from the images with a new remote version (if exists), making it possible to develop a feature across dockerized apps, tagged with a common name, e.g. new-tracking-field, to then test them all together in a CI environment with docker compose (see Run feature branches in a CI environment).

Use Cases

$ pose list services
sales-service
postgres
$ pose list volumes
sales-data
pg-data
$ pose list envs postgres
PORT=5432
POSTGRES_PASSWORD=password

Pose looks for the compose file following the spec as docker compose does, or you can specify the filename/s as following: pose -f compose.yaml -f another.yaml list services.

Execute pose --help for more options.

Pose can be helpful when working with large compose files, with dozens of definitions, where looking for something or summarize it can involve more work than without using pose.

Run feature branches in a CI environment

🐳 🖥 ⏯ ✅

Read this doc to learn how to use it for CI environments to run integration tests.

Find that service you don't remember exactly the name

If you have dozens of services defined, some of them even with similar names, can be hard to look at the file and find the one you don't remember the name, then pose list services come to the rescue ! it prints all on the standard output, so you can use something like pose list services | grep sales. Although you can cat compose.yaml | grep sales, with large files that can output a lot of undesired lines, e.g. lines with environment variables where the sales string is on it, and so on.

Get a full list of hosts names for /etc/hosts

This is my favorite:

$ pose list -p oneline services
sales-service postgres redis nginx ...

The -p oneline (or --pretty online) prints the list in one line, separating each item with a white space, why is it useful? you can then paste the output attached to a local IP in your /etc/hosts. Following the example:

127.0.0.1   sales-service postgres redis nginx ...

This is useful when trying to access to services ran with Docker Compose, and then you need to access them from the browser, or from an app outside Docker.

List environment variables from a service

It's specially useful when you want to centralize in one place all the environment variables used across all services for local development, but at some point you need to set up and run one or more services outside Docker. E.g.:

# Check the the services' environment variables
$ pose list envs sales-services
PORT=3000
DATABASE_URL=postgresql://sales:pass@postgres:5432/sales_dev
# Export them before run the service outside Docker
$ export $(pose list envs sales-services)
# Run the service, the envs have been set
$ yarn start
...
Webserver listening at http://localhost:3000

You can also export as an .env file the environment variables of any service:

$ pose list envs portal-webapp > .env

Install

Like any Rust project, install the binary pose in your system with:

$ cargo install docker-pose

(Yes, the package name in Crates.io is docker-pose, not pose).

Or from the source, after cloning the source code, go to the folder and execute cargo install --path . or make install (normally it will install the binary in the ~/.cargo/bin folder).

Binary Download

Binaries are made available each release for Linux, Mac and Windows.

Download the binary on the release page.

Once downloaded, untar the file:

$ tar -xvf pose*.tar.gz

Check for the execution bit:

$ chmod +x pose

and then execute pose:

$ ./pose

Include the directory Pose is in, in your PATH Variable if you wish to be able to execute it anywhere, or move Pose to a directory already included in your $PATH variable, like $HOME/.local/bin.

Build and run tests

🚧 Pose Development area! this is NOT a section of how to run tests with pose but instructions of how to build and test pose itself.

There is a Makefile that can be used to execute most of the development tasks, like make release that executes cargo build --release, so check out the file even if you don't use make to see useful commands.

Tests

• Run all the tests at once (slow): make test-all, include all tests, it's the equivalent of what CI executes on each push to GitHub.
• Rust unit tests: make test.
• Linter: make lint.
• Format checker: make fmt-check.
• Shell tests: make test-cmd. They are written in Shell script using the test framework Bats.
• Rust integration tests: make test-integration. Very slow, they execute tests to check functionality that involves pose → docker → docker registry.
• Shell integration tests: make test-cmd-integration, Very slow, they execute tests to check functionality that involves pose → docker → docker registry calling the command line.
• Run all the tests at once: make test-all-fast, including all the above, except integrations one.

If you get an error like make: ./tests/bats/bin/bats: Command not found, it’s because you cloned the project without the --recurse-submodules git argument. Execute first git submodule update --init to clone the submodules within the pose folder.

About

Source: https://github.com/mrsarm/pose

Authors: (2022-2024) Mariano Ruiz <mrsarm (at) gmail.com>

License: GPL-3