diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml index e580660..02c4abe 100644 --- a/.github/workflows/go.yml +++ b/.github/workflows/go.yml @@ -1,4 +1,4 @@ -name: Go +name: CI on: push: @@ -10,21 +10,28 @@ jobs: test: strategy: + fail-fast: false matrix: - go_version: [ '1.14', '1.15', '1.16', '1.17' ] + # 1.18 is the module floor (go.mod); oldstable/stable track the two + # most recent Go releases. + go-version: [ '1.18', 'oldstable', 'stable' ] os: [ 'ubuntu-latest', 'windows-latest', 'macOS-latest' ] runs-on: ${{ matrix.os }} steps: - - uses: actions/checkout@v2 + - uses: actions/checkout@v4 - - name: Use GO ${{ matrix.go_version }} - uses: actions/setup-go@v2 + - name: Use Go ${{ matrix.go-version }} + uses: actions/setup-go@v5 with: - go-version: ${{ matrix.go_version }} + go-version: ${{ matrix.go-version }} - - name: Test GO ${{ matrix.go_version }} + - name: Test run: go test ./... -race -coverprofile=coverage.txt -covermode=atomic - - name: Upload to codecov - if: ${{ matrix.os == 'ubuntu-latest' && matrix.go_version == '1.17' }} - run: bash <(curl -s https://codecov.io/bash) \ No newline at end of file + - name: Upload coverage to Codecov + if: ${{ matrix.os == 'ubuntu-latest' && matrix.go-version == 'stable' }} + uses: codecov/codecov-action@v5 + with: + token: ${{ secrets.CODECOV_TOKEN }} + files: ./coverage.txt + fail_ci_if_error: false diff --git a/CHANGELOG.md b/CHANGELOG.md new file mode 100644 index 0000000..faa910c --- /dev/null +++ b/CHANGELOG.md @@ -0,0 +1,73 @@ +# Changelog + +All notable changes to this project are documented in this file. + +The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), +and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html). +While the major version is `0`, the public API may change in any release. + +## [Unreleased] + +### Added + +- `CONTRIBUTING.md` describing setup, the test/lint workflow, code style, and the + commit/PR/release process. +- This `CHANGELOG.md`. + +### Fixed + +- CI is green again. The GitHub Actions workflow tested Go 1.14–1.17, which have + no `darwin/arm64` builds and so failed to install on the now-Apple-Silicon + `macOS-latest` runners, cancelling the whole matrix. The workflow now tests the + module's real floor (`1.18`) plus the two latest Go releases, sets + `fail-fast: false`, and upgrades to `actions/checkout@v4`, + `actions/setup-go@v5`, and `codecov/codecov-action@v5`. + +### Changed + +- Relicensed the project from the Apache License 2.0 to the MIT License. +- Reworked `README.md`: status badges, a tag reference table, the supported-type + list, an explicit default-precedence rule (CLI flag > `envVar` > `value` > zero + value), and a runnable example. + +## [0.0.3] - 2022-11-08 + +### Added + +- `uint` and `uint64` field types. + +### Changed + +- Converted the project to a Go module (`module github.com/memclutter/confparse`, + `go 1.18`). +- Replaced Travis CI with a GitHub Actions workflow running `go test ./... -race` + across a Go version matrix (1.14–1.17) on Linux, macOS, and Windows, and + uploading coverage to Codecov. +- Reworked the test suite into table-driven cases at 100% coverage, including the + default-value error paths for every supported type. + +## [0.0.2] - 2018-10-08 + +### Added + +- `int64` field type. + +## [0.0.1] - 2018-09-25 + +First release of `confparse` — a declarative command-line argument parser for Go. + +### Added + +- `Parse(container interface{}) error`, which reflects over a pointer-to-struct + and registers each field as a standard-library `flag`. +- Struct tags `name` (flag name), `value` (string default), `usage` (help text), + and `envVar` (environment-variable fallback for the default). +- Supported field types: `string`, `int`, `bool`, and `time.Duration`. +- Environment extension: when a field's `envVar` variable is set and non-empty, + its value becomes the field's default. + +[Unreleased]: https://github.com/memclutter/confparse/compare/v0.0.3...HEAD +[0.0.3]: https://github.com/memclutter/confparse/compare/v0.0.2...v0.0.3 +[0.0.2]: https://github.com/memclutter/confparse/compare/v0.0.1...v0.0.2 +[0.0.1]: https://github.com/memclutter/confparse/releases/tag/v0.0.1 + diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md new file mode 100644 index 0000000..b7c0fd7 --- /dev/null +++ b/CONTRIBUTING.md @@ -0,0 +1,89 @@ +# Contributing + +Thanks for your interest in improving `confparse`. This document describes how to +set up the project, the conventions the codebase follows, and how to get a change +merged. + +## Prerequisites + +- Go 1.18 or newer (the module targets `go 1.18`). +- That is all — `confparse` has no runtime dependencies beyond the standard + library, and the test suite needs no external services. + +## Getting started + +```bash +git clone https://github.com/memclutter/confparse.git +cd confparse +go mod download +go test ./... +``` + +`confparse` is a library, not a binary: there is nothing to run on its own. The +quickest way to exercise a change is to add or adjust a case in `parse_test.go`. + +## Development workflow + +- Branch off `main` with a short-lived topic branch; keep one logical change per + pull request. +- Run the checks below before pushing; CI must be green before review. + +```bash +go build ./... # compiles +go test ./... -race -coverprofile=cover.out # runs the suite with the race detector +gofmt -l . # must print nothing (formatting) +``` + +CI (`.github/workflows/go.yml`) runs `go test ./... -race` across a matrix of Go +versions and operating systems on every push and pull request, and uploads +coverage to Codecov. The suite is kept at 100% coverage — keep it there. + +## Code style + +- Format with `gofmt` / `goimports`; do not hand-format. +- Keep the public surface minimal: the package exposes a single function, + `Parse(container interface{}) error`. Treat it and the existing struct-tag + names (`name`, `value`, `usage`, `envVar`) as a stability contract. +- Wrap errors with context rather than returning bare errors where it adds + information. +- Prefer table-driven tests; every supported type and error path has a row in + `parse_test.go` — add one for anything you change. + +## Adding a supported type + +Supported field types are a contract. When adding one: + +1. Add a `case *T:` to the type switch in `declareFlag` (`parse.go`), converting + the `value` string into `T` and registering the matching `flag.TVar`. +2. Add a conversion helper if the type needs one, mirroring the existing + `toInt` / `toUint` / `toTimeDuration` helpers (return the conversion error). +3. Add success and error-path rows to `parse_test.go`, and document the type in + `README.md`. + +## Commit messages + +This project uses [Conventional Commits](https://www.conventionalcommits.org/): + +``` +feat(parse): support float64 fields +fix(parse): return error on invalid uint default +docs(readme): document default precedence +``` + +Use `feat` / `fix` / `docs` / `refactor` / `test` / `chore` as appropriate; mark +breaking changes with a `!` or a `BREAKING CHANGE:` footer. Adding a type or tag +extends the public contract — call it out in the message. + +## Pull requests + +- Describe what changes and why; link any related issue. +- Keep the diff focused and the history readable. +- Update `README.md` and `CHANGELOG.md` (under `## [Unreleased]`) when your change + affects behaviour users can see. + +## Releases + +Releases follow [Semantic Versioning](https://semver.org/). While the major +version is `0`, the public API may change in any release. 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IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. + diff --git a/README.md b/README.md index 8379d1b..c8897fa 100644 --- a/README.md +++ b/README.md @@ -1,52 +1,104 @@ -# Confparse +# confparse -[![Language Golang](https://img.shields.io/badge/language-golang-blue.svg)](https://img.shields.io/badge/language-golang-blue.svg) -[![Hex.pm](https://img.shields.io/hexpm/l/plug.svg)](https://github.com/memclutter/confparse) -[![codecov](https://codecov.io/gh/memclutter/confparse/branch/main/graph/badge.svg?token=G0U5MRSSFZ)](https://codecov.io/gh/memclutter/confparse) -[![Go](https://github.com/memclutter/confparse/actions/workflows/go.yml/badge.svg)](https://github.com/memclutter/confparse/actions/workflows/go.yml) +> Declarative command-line argument parser for Go — describe your configuration +> as a tagged struct and call `confparse.Parse`; fields become CLI flags, with +> per-field defaults and optional environment-variable fallbacks. -Declarative command line argument parser for golang projects. +[![Release](https://img.shields.io/github/v/release/memclutter/confparse?sort=semver)](https://github.com/memclutter/confparse/releases) +[![Go Reference](https://pkg.go.dev/badge/github.com/memclutter/confparse.svg)](https://pkg.go.dev/github.com/memclutter/confparse) +[![Go Report Card](https://goreportcard.com/badge/github.com/memclutter/confparse)](https://goreportcard.com/report/github.com/memclutter/confparse) +[![Go version](https://img.shields.io/github/go-mod/go-version/memclutter/confparse)](go.mod) +[![CI](https://github.com/memclutter/confparse/actions/workflows/go.yml/badge.svg)](https://github.com/memclutter/confparse/actions/workflows/go.yml) +[![codecov](https://codecov.io/gh/memclutter/confparse/branch/main/graph/badge.svg?token=G0U5MRSSFZ)](https://codecov.io/gh/memclutter/confparse) +[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE) + +`confparse` turns a configuration struct into command-line flags without the +boilerplate of wiring the standard `flag` package by hand. You declare each +option as a struct field with tags, call `Parse`, and read the populated struct. + +- **Declarative** — one struct describes the whole CLI surface. +- **Standard `flag` under the hood** — flags, defaults, and `-help` behave exactly + as Go developers expect. +- **Environment fallbacks** — any field can take its default from an environment + variable via a single tag. +- **Zero runtime dependencies** — only the Go standard library. + +## Contents + +- [Install](#install) +- [Usage](#usage) +- [Struct tags](#struct-tags) +- [Supported types](#supported-types) +- [Defaults and precedence](#defaults-and-precedence) +- [Example](#example) +- [Contributing](#contributing) +- [License](#license) ## Install -Install go module - ```shell go get github.com/memclutter/confparse ``` ## Usage -Use `struct` tags to declare command-line arguments. +Declare command-line arguments with `struct` tags and pass a pointer to `Parse`: ```go -// ... - type Config struct { - Argument1 string `name:"arg1" usage:"Argument 1 help text"` - Timeout time.Duration `name:"timeout" value:"200ms" usage:"Timeout argument"` + Addr string `name:"addr" value:":8000" usage:"Listen and serve address"` + Timeout time.Duration `name:"timeout" value:"200ms" usage:"Request timeout"` } -// ... +cfg := &Config{} +if err := confparse.Parse(cfg); err != nil { + log.Fatalf("parse configuration: %s", err) +} ``` -## Supported Types +`Parse` reads the tags off each field, registers a flag bound to that field, and +then parses `os.Args`. It returns an error only when a field's default `value` +cannot be parsed into the field's type. -Different types of arguments are supported: +## Struct tags + +| Tag | Meaning | +|----------|------------------------------------------------------------------| +| `name` | Flag name — `name:"addr"` registers `-addr`. | +| `value` | Default value, as a string, parsed into the field's type. | +| `usage` | Help text shown in the standard `flag` usage output. | +| `envVar` | Environment variable to source the default from (see below). | + +A field with no recognised tags, or of an unsupported type, is simply skipped. + +## Supported types + +```text +string int int64 uint uint64 bool time.Duration +``` -- `string` by default any arguments is a string -- `int` like `1`, `2`, `300`, `-23` etc -- `time.Duration` for time interval argument, like `10s`, `500ms`, `20us` etc -- `bool` for boolean argument +- `string` — used as-is (the default field type). +- `int`, `int64`, `uint`, `uint64` — parsed with `strconv`; e.g. `1`, `300`, `-23` + (signed types only). +- `bool` — `true` / `false`. +- `time.Duration` — Go duration syntax, e.g. `10s`, `500ms`, `20us`. -## Environment Extension +## Defaults and precedence -Use special struct tag `envVar` if you application read configuration from environment variables. -Set environment variable name in `envVar` and confparse read value from there. +For each field the effective default is resolved before the flag is parsed, then +the CLI flag (if present) wins: + +```text +CLI flag > environment variable (envVar) > value default > zero value +``` + +Set `envVar` to read a default from the environment. When that variable is set +and non-empty, its value replaces the `value` default; an empty or unset variable +is ignored. A passed `-name` flag always overrides whatever default was chosen. ## Example -The following is an example of defining a configuration for a simple web server +A small web server configured entirely through `confparse`: ```go package main @@ -59,7 +111,7 @@ import ( ) type Config struct { - Addr string `name:"addr" value:":8000" usage:"Listen and serve address"` + Addr string `name:"addr" value:":8000" usage:"Listen and serve address"` ApiKey string `name:"apiKey" envVar:"API_KEY" usage:"API key"` } @@ -70,13 +122,26 @@ func main() { log.Fatalf("Error parse configuration: %s", err) } - log.Printf("API Key: %s", appConfig.ApiKey) - + log.Printf("API Key: %s", appConfig.ApiKey) log.Printf("Listen and serve on %s", appConfig.Addr) if err := http.ListenAndServe(appConfig.Addr, nil); err != nil { log.Fatalf("Listen and serve error: %s", err) } } +``` +```shell +go run . -addr :9000 # -addr overrides the default +API_KEY=secret go run . # apiKey comes from the environment ``` +## Contributing + +Contributions are welcome — see [CONTRIBUTING.md](CONTRIBUTING.md) for setup, +coding conventions, and the commit/PR process. Changes are recorded in +[CHANGELOG.md](CHANGELOG.md). + +## License + +Released under the [MIT License](LICENSE). +