0.0.0.0 Initial commit, basic core functionality

.gitignore

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+.idea
+data
+dev
+logs

LICENSE

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+BSD 3-Clause License
+
+Copyright (c) 2024, Lixen Wraith
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

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+# Config
+
+A simple configuration management package for Go applications that supports TOML files and CLI arguments.
+
+## Features
+
+- TOML configuration with [tinytoml](https://github.com/LixenWraith/tinytoml)
+- Command line argument overrides with dot notation
+- Default config handling
+- Atomic file operations
+- No external dependencies beyond tinytoml
+
+## Installation
+
+```bash
+go get github.com/example/config
+```
+
+## Usage
+
+```go
+type AppConfig struct {
+    Server struct {
+        Host string `toml:"host"`
+        Port int    `toml:"port"`
+    } `toml:"server"`
+}
+
+func main() {
+    cfg := AppConfig{
+        Host: "localhost",
+        Port: 8080,
+    } // default config
+    exists, err := config.LoadConfig("config.toml", &cfg, os.Args[1:])
+    if err != nil {
+        log.Fatal(err)
+    }
+
+    if !exists {
+        if err := config.SaveConfig("config.toml", &cfg); err != nil {
+            log.Fatal(err)
+        }
+    }
+}
+```
+
+### CLI Arguments
+
+Override config values using dot notation:
+```bash
+./app --server.host localhost --server.port 8080
+```
+
+## API
+
+### `LoadConfig(path string, config interface{}, args []string) (bool, error)`
+Loads configuration from TOML file and CLI args. Returns true if config file exists.
+
+### `SaveConfig(path string, config interface{}) error`
+Saves configuration to TOML file atomically.
+
+## Limitations
+
+- Supports only basic Go types and structures supported by tinytoml
+- CLI arguments must use `--key value` format
+- Indirect dependency on [mapstructure](https://github.com/mitchellh/mapstructure) through tinytoml
+
+## License
+
+BSD-3

config.go

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+package config
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strconv"
+	"strings"
+
+	"github.com/LixenWraith/tinytoml"
+)
+
+type cliArg struct {
+	key   string
+	value string
+}
+
+func Load(path string, config interface{}, args []string) (bool, error) {
+	if config == nil {
+		return false, fmt.Errorf("config cannot be nil")
+	}
+
+	configExists := false
+	if stat, err := os.Stat(path); err == nil && !stat.IsDir() {
+		configExists = true
+		data, err := os.ReadFile(path)
+		if err != nil {
+			return false, fmt.Errorf("failed to read config file: %w", err)
+		}
+
+		if err := tinytoml.Unmarshal(data, config); err != nil {
+			return false, fmt.Errorf("failed to parse config file: %w", err)
+		}
+	}
+
+	if len(args) > 0 {
+		overrides, err := parseArgs(args)
+		if err != nil {
+			return configExists, fmt.Errorf("failed to parse CLI args: %w", err)
+		}
+
+		if err := mergeConfig(config, overrides); err != nil {
+			return configExists, fmt.Errorf("failed to merge CLI args: %w", err)
+		}
+	}
+
+	return configExists, nil
+}
+
+func Save(path string, config interface{}) error {
+	v := reflect.ValueOf(config)
+	if v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+
+	if v.Kind() != reflect.Struct {
+		return fmt.Errorf("config must be a struct or pointer to struct")
+	}
+
+	data, err := tinytoml.Marshal(v.Interface())
+	if err != nil {
+		return fmt.Errorf("failed to marshal config: %w", err)
+	}
+
+	dir := filepath.Dir(path)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return fmt.Errorf("failed to create config directory: %w", err)
+	}
+
+	tempFile := path + ".tmp"
+	if err := os.WriteFile(tempFile, data, 0644); err != nil {
+		return fmt.Errorf("failed to write temp config file: %w", err)
+	}
+
+	if err := os.Rename(tempFile, path); err != nil {
+		os.Remove(tempFile)
+		return fmt.Errorf("failed to save config file: %w", err)
+	}
+
+	return nil
+}
+
+func parseArgs(args []string) (map[string]interface{}, error) {
+	parsed := make([]cliArg, 0, len(args))
+	for i := 0; i < len(args); i++ {
+		arg := args[i]
+		if !strings.HasPrefix(arg, "--") {
+			continue
+		}
+
+		key := strings.TrimPrefix(arg, "--")
+		if i+1 >= len(args) || strings.HasPrefix(args[i+1], "--") {
+			parsed = append(parsed, cliArg{key: key, value: "true"})
+			continue
+		}
+
+		parsed = append(parsed, cliArg{key: key, value: args[i+1]})
+		i++
+	}
+
+	result := make(map[string]interface{})
+	for _, arg := range parsed {
+		keys := strings.Split(arg.key, ".")
+		current := result
+		for i, k := range keys[:len(keys)-1] {
+			if _, exists := current[k]; !exists {
+				current[k] = make(map[string]interface{})
+			}
+			if nested, ok := current[k].(map[string]interface{}); ok {
+				current = nested
+			} else {
+				return nil, fmt.Errorf("invalid nested key at %s", strings.Join(keys[:i+1], "."))
+			}
+		}
+
+		lastKey := keys[len(keys)-1]
+		if val, err := strconv.ParseBool(arg.value); err == nil {
+			current[lastKey] = val
+		} else if val, err := strconv.ParseInt(arg.value, 10, 64); err == nil {
+			current[lastKey] = val
+		} else if val, err := strconv.ParseFloat(arg.value, 64); err == nil {
+			current[lastKey] = val
+		} else {
+			current[lastKey] = arg.value
+		}
+	}
+
+	return result, nil
+}
+
+func mergeConfig(base interface{}, override map[string]interface{}) error {
+	baseValue := reflect.ValueOf(base)
+	if baseValue.Kind() != reflect.Ptr || baseValue.IsNil() {
+		return fmt.Errorf("base config must be a non-nil pointer")
+	}
+
+	data, err := json.Marshal(override)
+	if err != nil {
+		return fmt.Errorf("failed to marshal override values: %w", err)
+	}
+
+	if err := json.Unmarshal(data, base); err != nil {
+		return fmt.Errorf("failed to merge override values: %w", err)
+	}
+
+	return nil
+}

examples/main.go

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+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/LixenWraith/config"
+)
+
+type SMTPConfig struct {
+	Host     string `toml:"host"`
+	Port     string `toml:"port"`
+	FromAddr string `toml:"from_addr"`
+	AuthUser string `toml:"auth_user"`
+	AuthPass string `toml:"auth_pass"`
+}
+
+type ServerConfig struct {
+	Host         string        `toml:"host"`
+	Port         int           `toml:"port"`
+	ReadTimeout  time.Duration `toml:"read_timeout"`
+	WriteTimeout time.Duration `toml:"write_timeout"`
+	MaxConns     int           `toml:"max_conns"`
+}
+
+type AppConfig struct {
+	SMTP   SMTPConfig   `toml:"smtp"`
+	Server ServerConfig `toml:"server"`
+	Debug  bool         `toml:"debug"`
+}
+
+func main() {
+	defaultConfig := AppConfig{
+		SMTP: SMTPConfig{
+			Host:     "smtp.example.com",
+			Port:     "587",
+			FromAddr: "noreply@example.com",
+			AuthUser: "admin",
+			AuthPass: "default123",
+		},
+		Server: ServerConfig{
+			Host:         "localhost",
+			Port:         8080,
+			ReadTimeout:  time.Second * 30,
+			WriteTimeout: time.Second * 30,
+			MaxConns:     1000,
+		},
+		Debug: true,
+	}
+
+	configPath := filepath.Join(".", "test.toml")
+	cfg := defaultConfig
+
+	// CLI argument usage example to override SMTP host and server port of existing and default config:
+	// ./main --smtp.host mail.example.com --server.port 9090
+
+	exists, err := config.Load(configPath, &cfg, os.Args[1:])
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to load config: %v\n", err)
+		os.Exit(1)
+	}
+
+	if !exists {
+		if err := config.Save(configPath, &cfg); err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to save default config: %v\n", err)
+			os.Exit(1)
+		}
+		fmt.Println("Created default config at:", configPath)
+	}
+
+	fmt.Printf("Running with config:\n")
+	fmt.Printf("Server: %s:%d\n", cfg.Server.Host, cfg.Server.Port)
+	fmt.Printf("SMTP: %s:%s\n", cfg.SMTP.Host, cfg.SMTP.Port)
+	fmt.Printf("Debug: %v\n", cfg.Debug)
+}

go.mod

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+module config
+
+go 1.23.4
+
+require github.com/LixenWraith/tinytoml v0.0.0-20241125164826-37e61dcbf33b
+
+require github.com/mitchellh/mapstructure v1.5.0 // indirect

go.sum

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+github.com/LixenWraith/tinytoml v0.0.0-20241125164826-37e61dcbf33b h1:zjNL89uvvL9xB65qKXQGrzVOAH0CWkxRmcbU2uyyUk4=
+github.com/LixenWraith/tinytoml v0.0.0-20241125164826-37e61dcbf33b/go.mod h1:27w5bMp6NIrEuelM/8a+htswf0Dohs/AZ9tSsQ+lnN0=
+github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
+github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=

test.toml

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+debug = true
+[server]
+host = "localhost"
+max_conns = 1000
+port = 9090
+read_timeout = 30000000000
+write_timeout = 30000000000
+[smtp]
+auth_pass = "default123"
+auth_user = "admin"
+from_addr = "noreply@example.com"
+host = "mail.example.com"
+port = "587"