Initial commit

plugin/manager.go

@@ -0,0 +1,66 @@
+package plugin
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"sync/atomic"
+)
+
+var (
+	loaded  atomic.Bool
+	plugins []*Plugin
+)
+
+func Add(impl Impl) {
+	if loaded.Load() {
+		panic("cannot add plugin after server has started")
+	}
+	plugins = append(plugins, &Plugin{impl: impl})
+}
+
+func Initialize(log Logger, folder string) (func(context.Context) *sync.WaitGroup, error) {
+	if !loaded.CompareAndSwap(false, true) {
+		panic("plugins already initialized")
+	}
+
+	log.Infof("Loading %d plugin(s)...", len(plugins))
+
+	names := map[string]struct{}{}
+	for _, p := range plugins {
+		key := strings.ToLower(p.impl.Name())
+		if _, ok := names[key]; ok {
+			return nil, fmt.Errorf("duplicate plugin name: %s", p.impl.Name())
+		}
+		names[key] = struct{}{}
+	}
+
+	wd, err := os.Getwd()
+	if err != nil {
+		return nil, err
+	}
+
+	for _, p := range plugins {
+		p.logger = log
+		p.directory = filepath.Join(wd, folder, p.impl.Name())
+		if err := p.impl.Setup(p); err != nil {
+			return nil, fmt.Errorf("plugin '%s' setup failed: %w", p.impl.Name(), err)
+		}
+		log.Infof("Plugin '%s' loaded.", p.impl.Name())
+	}
+
+	return func(ctx context.Context) *sync.WaitGroup {
+		wg := &sync.WaitGroup{}
+		for _, p := range plugins {
+			wg.Add(1)
+			go func(p *Plugin) {
+				defer wg.Done()
+				p.impl.Run(ctx, p)
+			}(p)
+		}
+		return wg
+	}, nil
+}

plugin/plugin.go

@@ -0,0 +1,40 @@
+package plugin
+
+import (
+	"context"
+	"fmt"
+	"os"
+)
+
+type Impl interface {
+	Name() string
+	Setup(p *Plugin) error
+	Run(ctx context.Context, p *Plugin)
+}
+
+type Plugin struct {
+	impl             Impl
+	logger           Logger
+	directory        string
+	directoryCreated bool
+}
+
+type Logger interface {
+	Infof(format string, args ...any)
+	Warnf(format string, args ...any)
+	Errorf(format string, args ...any)
+	Debugf(format string, args ...any)
+}
+
+func (p *Plugin) Impl() Impl      { return p.impl }
+func (p *Plugin) Logger() Logger  { return p.logger }
+
+func (p *Plugin) DataFolder() string {
+	if !p.directoryCreated {
+		if err := os.MkdirAll(p.directory, os.ModePerm); err != nil {
+			panic(fmt.Sprintf("failed to create data folder for plugin %s: %v", p.impl.Name(), err))
+		}
+		p.directoryCreated = true
+	}
+	return p.directory
+}