governance/reference/pti/golang.rst

Project Testing Interface: Go

Go language (golang) repositories shall use the following interface for testing and automation purposes. This includes both pure golang repos and mixed-language repos as some of the OpenStack tooling defined for Python repos is re-used here.

A major criteria here is to not create an environment that is totally foreign to what developers are accustomed to in their respective communities. Remember these are first OpenStack projects and they follow OpenStack processes where feasible.

Each golang project must be able to do:

• Dependency installation
• Code style checks
• Unit tests
• Functional tests
• Test Coverage Report
• Documentation generation
• Translations import/export and merge for translated projects

There is not yet a consensus among the to golang community for build and package management tools as the go tool itself was intended to be sufficient. The traditional make(1) command is often used to supplement this role and provide the sort of interface that is common in many languages.

OpenStack has adopted the practice of using make for golang CTI as it provides a similar role fulfilled by tox in Python projects. It is also possible (and highly recommended) to use make to proxy tox or tox to proxy make in a mixed-language repo. Both tools use files that should remain transparent enough to most developers to understand what operations are actually being performed.

Specific commands

To drive the above tasks, the following commands should be supported in a clean tree:

make depend

Install dependencies required to build the project

make build

Execute build process

make install

Execute binary install

make test

Execute tests

make fmt

Execute code style checks

make docs

Generate HTML documentation from the in-tree developer docs

make godoc

Generate the golang docs from the source

make releasenotes

Generate HTML release notes

Additional commands may be supported, but are not required:

make cover

Generate coverage reports

make lint

Execute more code style checks

make translation

Perform translation-related tasks (TBD)

Project Setup

Project repos shall use a structure that is a hybrid of the typical OpenStack structure and those commonly found in the golang community. Because these are OpenStack projects, the top-level structure shall contain the existing process-related components. All golang source code and modules shall be in one or more subdirectories named in a manner to identify its contents distinctly from the Python namespace directories currently used. This allows the golang code to maintain its native style and not be mixed in with the OpenStack tool-related pieces such as Sphinx documentation and Reno release notes.

The source subdirectory naming is intentionally flexible in order to accommodate unforeseen situations, however the following guidelines should be strongly considered:

• Simple projects or projects that only need one golang workspace can use a single top-level directory named go.
• Projects that may have multiple distinct golang workspaces should use names that include a -go suffix. This allows similarly named modules in multiple languages to co-exist. For example: the CloudTool project should continue to put Python sources in its Python namespace cloudtool and the golang source in cloudtool-go (do not use a period!).

Dependency Management

OpenStack has chosen to use Glide as the common dependency management tool for golang. The depend target provides a common interface to Glide's install command.

make depend

Install dependencies required to build the project

Golang dependencies shall not be vendored in golang repos. Each project shall include a list of its dependencies and acceptable/tested versions in the repo. The required dependencies shall be installed into a golang workspace compatible with the results of running go get.

Dependencies are specified in golang via full paths of the form opendev.org/openstack/golang-client. All dependencies that are OpenStack projects will be required to use the opendev.org host to minimize unnecessary mirrors.

To support OpenStack CI and to ensure the Depends-On footers work properly, this target must not modify existing git repo state for a given dependency if the git repository is already present in ${GOPATH}/src/${repo}. The CI system will pre-populate all necessary git repos that it knows about into the appropriate locations in the appropriate states.

External dependencies outside of the OpenStack CI should be installed as usual. It is expected that a mirror of required dependencies will be maintained in the CI system.

Further details will be included here as the dependency tooling is finalized.

Build and Install

The golang toolchain automatically performs the build step when required by other operations such as go test. Build and install are split out here as they are common operations and useful in their own right. These targets are not strictly necessary for CI testing.

make build

Execute build process

make install

Execute binary install

Codestyle Checks

OpenStack uses gofmt directly to check for proper coding style. As we do not want to be making changes to the repo in CI the default target shall not use go fmt which rewrites source files by default. As a developer convenience a second target called fmtfix shall be defined that does the source fixups (equivalent to gofmt -l -w).

make fmt

Run the gofmt tool non-destructively to validate code formatting

make fmtfix

Run the gofmt tool and overwrite source files with gofmt's version if changes are required. This is primarily a developer convenience.

Tests

OpenStack uses go test to run all test types at once invoked via the Makefile.

make test

Run tests

This is the general test target and may simply call some subset of additional test-* targets. Specific test targets should be named with a test-* prefix as a convention.

Go test output is not natively in a format consumable by subunit, however there is at least one tool available that can easily be made to support subunit.

Generated Files

ChangeLog and AUTHORS files are generated at <TBD>.

.mailmap files should exist where a developer has more than one email address or identity, and should map to the developer's canonical identity.

Documentation

Narrative Documentation

In order to reuse existing templates, styles, and tooling, OpenStack uses Sphinx to generate our Narrative Project documentation.

In addition to the normal PTI pti-documentation requirements, for developer convenience, Go projects are recommended to provide:

make docs

Generate HTML documentation from the in-tree developer docs

that should:

• Either install any needed distro dependencies from the doc tag in bindep.txt or emit an error if they are not installed.
• Install Python dependencies for Sphinx from doc/requirements.txt.
• Execute sphinx-build -W -b html doc/source doc/build

Source

Go has a well-defined documentation tool godoc that produces developer documentation extracted from source code comments, similar to Python's Docstring.

make godoc

Generate the golang docs from the source

Release notes

OpenStack uses Reno to manage release notes. This uses Sphinx to generate the final HTML documentation.

In addition to the normal PTI pti-documentation requirements, for developer convenience, Go projects are recommended to provide:

make releasenotes

Generate HTML release notes

Translations

A common translation process is not yet well-defined in the golang community. This section will be completed once a process is developed that is compatible with the existing OpenStack translation workflow.

Build Tools

A number of the tools used by OpenStack projects are written in Python and require local developer installation. This is something that tox is very good at and shall be used to manage those tools in its local virtual environments.

These tools should all be Python 3 compatible so non-Python projects should use only Python 3 in their local virtual environments for tooling support.