From dd3d5cfc0014e5f7ce529602cac09a1de41bdc3d Mon Sep 17 00:00:00 2001
From: Slack Coder <slackcoder@server.ky>
Date: Mon, 21 Oct 2024 08:59:36 -0500
Subject: Support multiple config files

Read files from /etc/mirror/conf.d.
---
 cmd/mirror/main.go                   | 22 +++++++++++---
 contrib/slackbuild/mirror.SlackBuild |  1 +
 contrib/slackbuild/rc.mirror         |  2 +-
 internal/service/config.go           | 59 ++++++++++++++++++++++++++++--------
 internal/service/service.go          |  2 +-
 5 files changed, 66 insertions(+), 20 deletions(-)

diff --git a/cmd/mirror/main.go b/cmd/mirror/main.go
index e823039..e8a00ac 100644
--- a/cmd/mirror/main.go
+++ b/cmd/mirror/main.go
@@ -13,14 +13,16 @@ import (
 var Version string
 
 type Flags struct {
-	Config  string
-	Version bool
+	Config    string
+	ConfigDir string
+	Version   bool
 }
 
 func ParseFlags() *Flags {
 	var flags Flags
 
-	flag.StringVar(&flags.Config, "config", "/etc/mirror/mirror.toml", "configuration file")
+	flag.StringVar(&flags.Config, "config", "/etc/mirror/mirror.toml", "configuration file which takes precedence")
+	flag.StringVar(&flags.ConfigDir, "config-dir", "/etc/mirror/conf.d", "configuration directory")
 	flag.BoolVar(&flags.Version, "version", false, "print version")
 
 	flag.Parse()
@@ -39,13 +41,23 @@ func main() {
 
 	if flags.Version {
 		fmt.Println(Version)
+
 		os.Exit(0)
 	}
 
-	cfg, err := service.ReadConfig(flags.Config)
+	var cfg service.Config
+
+	c, err := service.ReadConfigDir(flags.ConfigDir)
+	exitOnError(err)
+
+	cfg.Append(c)
+
+	c, err = service.ReadConfig(flags.Config)
 	exitOnError(err)
 
-	srv, err := service.NewService(cfg)
+	cfg.Append(c)
+
+	srv, err := service.NewService(&cfg)
 	exitOnError(err)
 
 	err = srv.Run()
diff --git a/contrib/slackbuild/mirror.SlackBuild b/contrib/slackbuild/mirror.SlackBuild
index 9dadca2..fb1b92e 100644
--- a/contrib/slackbuild/mirror.SlackBuild
+++ b/contrib/slackbuild/mirror.SlackBuild
@@ -64,6 +64,7 @@ mkdir -p "$PKG/etc/rc.d"
 cat "$CWD/rc.mirror" > "$PKG/etc/rc.d/rc.mirror.new"
 mkdir -p $PKG/etc/mirror
 cat "$CWD/mirror.toml" > "$PKG/etc/mirror/mirror.toml.new"
+mkdir -p $PKG/etc/mirror/conf.d
 mkdir -p "$PKG/var/log/mirror"
 
 cd "$PKG"
diff --git a/contrib/slackbuild/rc.mirror b/contrib/slackbuild/rc.mirror
index df3c72f..362a3f1 100644
--- a/contrib/slackbuild/rc.mirror
+++ b/contrib/slackbuild/rc.mirror
@@ -20,7 +20,7 @@ start() {
     --user=mirror \
     --pidfiles=/run/mirror \
     --output=/var/log/mirror/mirror.log \
-    -- mirror -config /etc/mirror/mirror.toml
+    -- mirror
 }
 
 stop() {
diff --git a/internal/service/config.go b/internal/service/config.go
index 27368b3..bfe271e 100644
--- a/internal/service/config.go
+++ b/internal/service/config.go
@@ -3,6 +3,8 @@ package service
 import (
 	"fmt"
 	"os"
+	"path"
+	"path/filepath"
 	"time"
 
 	"git.server.ky/slackcoder/mirror/internal"
@@ -13,6 +15,10 @@ type Duration struct {
 	time.Duration
 }
 
+func DurationRef(v time.Duration) *Duration {
+	return &Duration{v}
+}
+
 func (s Duration) MarshalText() ([]byte, error) {
 	return []byte(s.Duration.String()), nil
 }
@@ -29,8 +35,8 @@ func (s *Duration) UnmarshalText(text []byte) error {
 
 // Global parameters
 type GlobalConfig struct {
-	MaxInterval Duration `toml:"max-interval"`
-	MinInterval Duration `toml:"min-interval"`
+	MaxInterval *Duration `toml:"max-interval"`
+	MinInterval *Duration `toml:"min-interval"`
 }
 
 type Config struct {
@@ -44,18 +50,17 @@ func (c *Config) String() string {
 
 var DefaultConfig = Config{
 	GlobalConfig: GlobalConfig{
-		MaxInterval: Duration{24 * time.Hour},
-		MinInterval: Duration{time.Hour},
+		MaxInterval: DurationRef(24 * time.Hour),
+		MinInterval: DurationRef(time.Hour),
 	},
 }
 
+// Read the given configuration file.
 func ReadConfig(fp string) (*Config, error) {
 	var config Config
 
 	f, err := os.Open(fp)
-	if os.IsNotExist(err) {
-		return nil, nil
-	} else if err != nil {
+	if err != nil {
 		return nil, err
 	}
 	defer f.Close()
@@ -68,14 +73,42 @@ func ReadConfig(fp string) (*Config, error) {
 	return &config, nil
 }
 
-func (c *Config) Merge(src *Config) {
-	if c.MaxInterval.Duration == 0 && src.MaxInterval.Duration != 0 {
+// Read all configuration in the given directory.
+func ReadConfigDir(fp string) (*Config, error) {
+	var cfg Config
+
+	confDPath := path.Join(path.Join(fp, "conf.d"))
+	confDDir, err := os.ReadDir(confDPath)
+	if os.IsNotExist(err) {
+		// No directory is an empty one.
+		return &Config{}, nil
+	} else if err != nil {
+		return nil, err
+	}
+
+	for _, entry := range confDDir {
+		if filepath.Ext(entry.Name()) != ".toml" {
+			continue
+		}
+
+		entryCfg, err := ReadConfig(filepath.Join(confDPath, entry.Name()))
+		if err != nil {
+			return nil, err
+		}
+
+		cfg.Append(entryCfg)
+	}
+
+	return &cfg, nil
+}
+
+// Apply the given configuration parameters.
+func (c *Config) Append(src *Config) {
+	if src.MaxInterval != nil {
 		c.MaxInterval = src.MaxInterval
 	}
-	if c.MinInterval.Duration == 0 && src.MinInterval.Duration != 0 {
+	if src.MinInterval != nil {
 		c.MinInterval = src.MinInterval
 	}
-	if len(c.Mirrors) == 0 {
-		c.Mirrors = src.Mirrors
-	}
+	c.Mirrors = append(c.Mirrors, src.Mirrors...)
 }
diff --git a/internal/service/service.go b/internal/service/service.go
index 637a1cf..21df14b 100644
--- a/internal/service/service.go
+++ b/internal/service/service.go
@@ -32,7 +32,7 @@ type Service struct {
 
 func NewService(cfg *Config) (*Service, error) {
 	// Apply  defaults
-	cfg.Merge(&DefaultConfig)
+	cfg.Append(&DefaultConfig)
 
 	for _, cmd := range requiredCommands {
 		if err := internal.RequireCommand(cmd); err != nil {
-- 
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