add the concept of processors

internals/processing/processor.go

@@ -0,0 +1,45 @@
+package processing
+
+import (
+	"context"
+	"fmt"
+	"sync"
+)
+
+type Processor interface {
+	Type() string
+	Process(context.Context, any) (any, error)
+}
+
+type ProcessorConfig struct {
+	Type   string         `json:"type"`
+	Params map[string]any `json:"params"`
+}
+
+type ProcessorRegistration struct {
+	Type string `json:"type"`
+	New  func(ProcessorConfig) (Processor, error)
+}
+
+func RegisterProcessor(processor ProcessorRegistration) {
+
+	if processor.Type == "" {
+		panic("processor type is missing")
+	}
+	if processor.New == nil {
+		panic("missing ProcessorRegistration.New")
+	}
+
+	processorRegistryMu.Lock()
+	defer processorRegistryMu.Unlock()
+
+	if _, ok := ProcessorRegistry[string(processor.Type)]; ok {
+		panic(fmt.Sprintf("processor already registered: %s", processor.Type))
+	}
+	ProcessorRegistry[string(processor.Type)] = processor
+}
+
+var (
+	processorRegistryMu sync.RWMutex
+	ProcessorRegistry   = make(map[string]ProcessorRegistration)
+)