circleci-config

Go library to work with CircleCI config files.

Features

Currently, only implements feature required for config inference:

Rules for labeling codebases

The labeling package implements rules for detecting the tech stack used in a codebase:

c := codebase.LocalCodebase{}
labels := labeling.ApplyAllRules(c)
// labels: map of keys like "deps:node" to a Label structure containing more details

Rules for different stacks can be found in the internal directory.

Generating jobs for a given set of labels

The generation package takes a set of labels and produces CI jobs for them, and then assembles them into a config:

config := generation.GenerateConfig(labels)
// config: data structure that represents a CircleCI config with workflows, jobs, orbs, etc.

Config serialization to YAML

The config package defines structs that represent a CircleCI config and that can be serialized to YAML.

See the TestConfig_YamlNode test for an example.

yamlNode := config.YamlNode() // yamlNode: a gopkg.in/yaml.v3 yaml.Node
// or
yamlText := config.String()

Not all possible configs can be represented, only the ones needed for inference.

Adding a new language or software stack

Adding support for a new stack consists of three parts:

1. Define label keys to identify the stack and its variants. Add "deps:..." keys for dependency management, "test:..." keys for test runners, and "build:..." keys for build systems (if they are different).
2. Implementing rules that label codebases with the above keys in the labeling/internal directory. Create a new file for each language. Then add those rules to the ApplyAllRules function.
3. Implement a function that given those rules generates jobs in the generation/internal directory. Again, create a new file for each language. Add that function to the list of calls in GenerateConfig.

Of course, also add tests for the new rules and config generation code.

CLI

A simple CLI for experimenting with inference is included. Build it with

go build ./cmd/inferconfig/inferconfig.go

Then invoke it with a path to print config for the codebase in that path to stdout.