feat: add since init subcommand to scaffold config file

README.md

@@ -35,6 +35,9 @@ go install github.com/release-tools/since
 - [version](#project-version)
 - [release](#project-release)
 
+**Config** - Scaffold a config file for the tool.
+- [init](#init)
+
 ---
 
 ### `changelog generate`
@@ -202,10 +205,35 @@ Global Flags:
   -t, --tag string         Include commits after this tag
 ```
 
+---
+
+### `init`
+
+Creates a new `since.yaml` config file, pre-populated with commented
+examples for branch requirements, pre/post hook scripts, and commit
+exclusions. If the file already exists, it is overwritten.
+
+```
+Usage:
+  since init [flags]
+
+Flags:
+  -h, --help            help for init
+  -o, --output string   Directory to write the config file to (default: current directory)
+
+Global Flags:
+  -l, --log-level string   Log level (debug, info, warn, error, fatal, panic) (default "debug")
+  -q, --quiet              Disable logging (useful for scripting)
+```
+
+---
+
 #### The `since.yaml` file
 
 You can also use a `since.yaml` file to configure the tool. This file should be placed in the root of your project repository.
 
+The quickest way to start is `since init`, which drops a fully commented example config into your project. Uncomment the bits you need.
+
 ```yaml
 # require us to be on the main branch
 requireBranch: main

cfg/config.go

@@ -37,11 +37,11 @@ type SinceConfig struct {
 	Ignore        []string `yaml:"ignore"`
 }
 
-const defaultConfigFile = "since.yaml"
+const DefaultConfigFile = "since.yaml"
 
 // LoadConfig loads the YAML config file from the given directory.
 func LoadConfig(dir string) (SinceConfig, error) {
-	return loadConfig(path.Join(dir, defaultConfigFile))
+	return loadConfig(path.Join(dir, DefaultConfigFile))
 }
 
 // loadConfig loads the YAML config file from the given path.

cfg/config_test.go

@@ -69,7 +69,7 @@ func Test_loadConfig(t *testing.T) {
 func TestLoadConfig(t *testing.T) {
 	dir := t.TempDir()
 	content := "requireBranch: main\nbefore:\n  - command: echo\n    args:\n      - hello world\n"
-	if err := os.WriteFile(path.Join(dir, defaultConfigFile), []byte(content), 0644); err != nil {
+	if err := os.WriteFile(path.Join(dir, DefaultConfigFile), []byte(content), 0644); err != nil {
 		t.Fatal(err)
 	}
 

cmd/init.go

@@ -0,0 +1,81 @@
+/*
+Copyright © 2023 Pete Cornish <outofcoffee@gmail.com>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cmd
+
+import (
+	_ "embed"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/release-tools/since/cfg"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+//go:embed templates/since.yaml
+var defaultConfig string
+
+var initSubCmd struct {
+	outputFile string
+}
+
+// initSubCmd represents the init subcommand
+var initSubCmdCmd = &cobra.Command{
+	Use:   "init",
+	Short: "Create a new since.yaml config file",
+	Long: `Creates a new since.yaml config file with example configuration,
+including branch requirements, pre/post hook scripts, and commit exclusions.
+If the config file already exists, it will be overwritten.`,
+	Args:          cobra.NoArgs,
+	SilenceUsage:  true,
+	SilenceErrors: true,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return runInit()
+	},
+}
+
+func runInit() error {
+	configDir := initSubCmd.outputFile
+	if configDir == "" {
+		var err error
+		configDir, err = os.Getwd()
+		if err != nil {
+			return fmt.Errorf("failed to get current directory: %w", err)
+		}
+	}
+	configPath := filepath.Join(configDir, cfg.DefaultConfigFile)
+
+	if _, err := os.Stat(configPath); err == nil {
+		logrus.Warnf("config file '%s' already exists, overwriting", configPath)
+	} else if !os.IsNotExist(err) {
+		return fmt.Errorf("failed to check config file: %w", err)
+	}
+
+	if err := os.WriteFile(configPath, []byte(defaultConfig), 0644); err != nil {
+		return fmt.Errorf("failed to write config file: %w", err)
+	}
+
+	logrus.Infof("created config file '%s'", configPath)
+	return nil
+}
+
+func init() {
+	rootCmd.AddCommand(initSubCmdCmd)
+
+	initSubCmdCmd.Flags().StringVarP(&initSubCmd.outputFile, "output", "o", "", "Directory to write the config file to (default: current directory)")
+}