Microservice Repository Template

This is a template for GitHub repositories containing one Python-based microservice (optimal for a multirepository setup).

It features:

• Continuous Templation - A continuous update-delivery mechanism for templated repositories
• A devcontainer-based fully-configured development environment for vscode
• Tight linting and formatting using Ruff
• Static type checking using mypy
• Security scanning using bandit
• A structure for automated tests using pytest
• Dependency locking using pip-tools
• Git hooks checking linting and formatting before committing using pre-commit
• Automatic container-building and publishing to Docker Hub
• GitHub Actions for automating or checking all of the above

It is worth emphasizing the first point, this template is not just a one-time kickstart for your project but repositories created using this template will continue receiving updates as the template evolves. For further details, please look at the explanation in .template/README.md.

Please also refer to .readme_generation/README.md for details on how to adapt this readme.

Here the intro to the template stops and the actual template for the readme of the microservice starts:

---

My Microservice

My-Microservice - a short description

Description

Here you should provide a short summary of the purpose of this microservice.

Installation

We recommend using the provided Docker container.

A pre-build version is available at docker hub:

docker pull ghga/my-microservice:0.1.0

Or you can build the container yourself from the ./Dockerfile:

# Execute in the repo's root dir:
docker build -t ghga/my-microservice:0.1.0 .

For production-ready deployment, we recommend using Kubernetes, however, for simple use cases, you could execute the service using docker on a single server:

# The entrypoint is preconfigured:
docker run -p 8080:8080 ghga/my-microservice:0.1.0 --help

If you prefer not to use containers, you may install the service from source:

# Execute in the repo's root dir:
pip install .

# To run the service:
my_microservice --help

Configuration

Parameters

The service requires the following configuration parameters:

• log_level (string): The minimum log level to capture. Must be one of: ["CRITICAL", "ERROR", "WARNING", "INFO", "DEBUG", "TRACE"]. Default: "INFO".

• service_name (string): Short name of this service. Default: "my_microservice".

• service_instance_id (string): A string that uniquely identifies this instance across all instances of this service. This is included in log messages.

  Examples:

  "germany-bw-instance-001"

• log_format: If set, will replace JSON formatting with the specified string format. If not set, has no effect. In addition to the standard attributes, the following can also be specified: timestamp, service, instance, level, correlation_id, and details. Default: null.

  • Any of

    • string

    • null

  Examples:

  "%(timestamp)s - %(service)s - %(level)s - %(message)s"

  "%(asctime)s - Severity: %(levelno)s - %(msg)s"

• host (string): IP of the host. Default: "127.0.0.1".

• port (integer): Port to expose the server on the specified host. Default: 8080.

• auto_reload (boolean): A development feature. Set to True to automatically reload the server upon code changes. Default: false.

• workers (integer): Number of workers processes to run. Default: 1.

• api_root_path (string): Root path at which the API is reachable. This is relative to the specified host and port. Default: "".

• openapi_url (string): Path to get the openapi specification in JSON format. This is relative to the specified host and port. Default: "/openapi.json".

• docs_url (string): Path to host the swagger documentation. This is relative to the specified host and port. Default: "/docs".

• cors_allowed_origins: A list of origins that should be permitted to make cross-origin requests. By default, cross-origin requests are not allowed. You can use ['*'] to allow any origin. Default: null.

  • Any of

    • array

      • Items (string)

    • null

  Examples:

  [
      "https://example.org",
      "https://www.example.org"
  ]

• cors_allow_credentials: Indicate that cookies should be supported for cross-origin requests. Defaults to False. Also, cors_allowed_origins cannot be set to ['*'] for credentials to be allowed. The origins must be explicitly specified. Default: null.

  • Any of

    • boolean

    • null

  Examples:

  [
      "https://example.org",
      "https://www.example.org"
  ]

• cors_allowed_methods: A list of HTTP methods that should be allowed for cross-origin requests. Defaults to ['GET']. You can use ['*'] to allow all standard methods. Default: null.

  • Any of

    • array

      • Items (string)

    • null

  Examples:

  [
      "*"
  ]

• cors_allowed_headers: A list of HTTP request headers that should be supported for cross-origin requests. Defaults to []. You can use ['*'] to allow all headers. The Accept, Accept-Language, Content-Language and Content-Type headers are always allowed for CORS requests. Default: null.

  • Any of

    • array

      • Items (string)

    • null

  Examples:

  []

• generate_correlation_id (boolean): A flag, which, if False, will result in an error when inbound requests don't possess a correlation ID. If True, requests without a correlation ID will be assigned a newly generated ID in the correlation ID middleware function. Default: true.

  Examples:

  true

  false

• language (string): The language. Must be one of: ["Greek", "Croatian", "French", "German"]. Default: "Croatian".

Usage:

A template YAML for configurating the service can be found at ./example-config.yaml. Please adapt it, rename it to .my_microservice.yaml, and place it into one of the following locations:

• in the current working directory were you are execute the service (on unix: ./.my_microservice.yaml)
• in your home directory (on unix: ~/.my_microservice.yaml)

The config yaml will be automatically parsed by the service.

Important: If you are using containers, the locations refer to paths within the container.

All parameters mentioned in the ./example-config.yaml could also be set using environment variables or file secrets.

For naming the environment variables, just prefix the parameter name with my_microservice_, e.g. for the host set an environment variable named my_microservice_host (you may use both upper or lower cases, however, it is standard to define all env variables in upper cases).

To using file secrets please refer to the corresponding section of the pydantic documentation.

HTTP API

An OpenAPI specification for this service can be found here.

Architecture and Design:

This is a Python-based service following the Triple Hexagonal Architecture pattern. It uses protocol/provider pairs and dependency injection mechanisms provided by the hexkit library.

Development

For setting up the development environment, we rely on the devcontainer feature of VS Code in combination with Docker Compose.

To use it, you have to have Docker Compose as well as VS Code with its "Remote - Containers" extension (ms-vscode-remote.remote-containers) installed. Then open this repository in VS Code and run the command Remote-Containers: Reopen in Container from the VS Code "Command Palette".

This will give you a full-fledged, pre-configured development environment including:

• infrastructural dependencies of the service (databases, etc.)
• all relevant VS Code extensions pre-installed
• pre-configured linting and auto-formatting
• a pre-configured debugger
• automatic license-header insertion

Moreover, inside the devcontainer, a convenience commands dev_install is available. It installs the service with all development dependencies, installs pre-commit.

The installation is performed automatically when you build the devcontainer. However, if you update dependencies in the ./pyproject.toml or the ./requirements-dev.txt, please run it again.

License

This repository is free to use and modify according to the Apache 2.0 License.

README Generation

This README file is auto-generated, please see readme_generation.md for details.