Handle config, parse flags

internal/config/config.go

@@ -0,0 +1,176 @@
+// This file is part of the happyDeliver (R) project.
+// Copyright (c) 2025 happyDomain
+// Authors: Pierre-Olivier Mercier, et al.
+//
+// This program is offered under a commercial and under the AGPL license.
+// For commercial licensing, contact us at <contact@happydomain.org>.
+//
+// For AGPL licensing:
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package config
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"path"
+	"strings"
+	"time"
+
+	openapi_types "github.com/oapi-codegen/runtime/types"
+)
+
+// Config represents the application configuration
+type Config struct {
+	DevProxy string
+	Bind     string
+	Database DatabaseConfig
+	Email    EmailConfig
+	Analysis AnalysisConfig
+}
+
+// DatabaseConfig contains database connection settings
+type DatabaseConfig struct {
+	Type string
+	DSN  string
+}
+
+// EmailConfig contains email domain and routing settings
+type EmailConfig struct {
+	Domain            string
+	TestAddressPrefix string
+}
+
+// AnalysisConfig contains timeout and behavior settings for email analysis
+type AnalysisConfig struct {
+	DNSTimeout  time.Duration
+	HTTPTimeout time.Duration
+	RBLs        []string
+}
+
+// DefaultConfig returns a configuration with sensible defaults
+func DefaultConfig() *Config {
+	return &Config{
+		DevProxy: "",
+		Bind:     ":8080",
+		Database: DatabaseConfig{
+			Type: "sqlite",
+			DSN:  "happydeliver.db",
+		},
+		Email: EmailConfig{
+			Domain:            "happydeliver.local",
+			TestAddressPrefix: "test-",
+		},
+		Analysis: AnalysisConfig{
+			DNSTimeout:  5 * time.Second,
+			HTTPTimeout: 10 * time.Second,
+			RBLs:        []string{},
+		},
+	}
+}
+
+// ConsolidateConfig fills an Options struct by reading configuration from
+// config files, environment, then command line.
+//
+// Should be called only one time.
+func ConsolidateConfig() (opts *Config, err error) {
+	// Define defaults options
+	opts = DefaultConfig()
+
+	declareFlags(opts)
+
+	// Establish a list of possible configuration file locations
+	configLocations := []string{
+		"happydeliver.conf",
+	}
+
+	if home, err := os.UserConfigDir(); err == nil {
+		configLocations = append(
+			configLocations,
+			path.Join(home, "happydeliver", "happydeliver.conf"),
+			path.Join(home, "happydomain", "happydeliver.conf"),
+		)
+	}
+
+	configLocations = append(configLocations, path.Join("etc", "happydeliver.conf"))
+
+	// If config file exists, read configuration from it
+	for _, filename := range configLocations {
+		if _, e := os.Stat(filename); !os.IsNotExist(e) && !os.IsPermission(e) {
+			log.Printf("Loading configuration from %s\n", filename)
+			err = parseFile(opts, filename)
+			if err != nil {
+				return
+			}
+			break
+		}
+	}
+
+	// Then, overwrite that by what is present in the environment
+	err = parseEnvironmentVariables(opts)
+	if err != nil {
+		return
+	}
+
+	// Finaly, command line takes precedence
+	err = parseCLI(opts)
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+// Validate checks if the configuration is valid
+func (c *Config) Validate() error {
+	if c.Email.Domain == "" {
+		return fmt.Errorf("email domain cannot be empty")
+	}
+
+	if _, err := openapi_types.Email(fmt.Sprintf("%s1234-5678-9090@%s", c.Email.TestAddressPrefix, c.Email.Domain)).MarshalJSON(); err != nil {
+		return fmt.Errorf("invalid email domain: %w", err)
+	}
+
+	if c.Database.Type != "sqlite" && c.Database.Type != "postgres" {
+		return fmt.Errorf("unsupported database type: %s", c.Database.Type)
+	}
+
+	if c.Database.DSN == "" {
+		return fmt.Errorf("database DSN cannot be empty")
+	}
+
+	return nil
+}
+
+// parseLine treats a config line and place the read value in the variable
+// declared to the corresponding flag.
+func parseLine(o *Config, line string) (err error) {
+	fields := strings.SplitN(line, "=", 2)
+	orig_key := strings.TrimSpace(fields[0])
+	value := strings.TrimSpace(fields[1])
+
+	if len(value) == 0 {
+		return
+	}
+
+	key := strings.TrimPrefix(strings.TrimPrefix(orig_key, "HAPPYDELIVER_"), "HAPPYDOMAIN_")
+	key = strings.Replace(key, "_", "-", -1)
+	key = strings.ToLower(key)
+
+	err = flag.Set(key, value)
+
+	return
+}