homelab-frontend/internal/serviceadapter/workflow_adapter.go

package serviceadapter

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net/http"

	"forgejo.riotpiao.com/rock/homelab-frontend/internal/temporal"
)

// WorkflowAdapter handles X-Service: workflow requests.
// It forwards workflow operations to the Temporal gRPC service.
// Users can specify namespace via the request payload.
type WorkflowAdapter struct {
	temporalHandler *temporal.Handler
}

// NewWorkflowAdapter creates a new WorkflowAdapter.
func NewWorkflowAdapter(handler *temporal.Handler) *WorkflowAdapter {
	return &WorkflowAdapter{
		temporalHandler: handler,
	}
}

// resourceToAction maps X-Resource names to Temporal action names.
var resourceToAction = map[string]string{
	"execute":    "START_WORKFLOW",
	"describe":   "DESCRIBE_WORKFLOW",
	"list":       "LIST_WORKFLOWS",
	"history":    "GET_WORKFLOW_HISTORY",
	"terminate":  "TERMINATE_WORKFLOW",
	"cancel":     "CANCEL_WORKFLOW",
	"signal":     "SIGNAL_WORKFLOW",
	"query":      "QUERY_WORKFLOW",
	"reset":      "RESET_WORKFLOW",
	"update":     "UPDATE_WORKFLOW",
}

// ServeHTTP implements http.Handler for X-Service: workflow routing.
// Maps X-Resource header to Temporal action, injects action into body,
// and forwards to the temporal handler.
func (wa *WorkflowAdapter) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	resource := r.Header.Get("X-Resource")
	action, ok := resourceToAction[resource]
	if !ok {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprintf(w, `{"error":"unknown workflow resource: %s"}`, resource)
		return
	}

	// Read body, inject action, forward
	body, err := io.ReadAll(r.Body)
	if err != nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusBadRequest)
		fmt.Fprintf(w, `{"error":"failed to read body: %s"}`, err.Error())
		return
	}

	var payload map[string]interface{}
	if len(body) > 0 {
		if err := json.Unmarshal(body, &payload); err != nil {
			w.Header().Set("Content-Type", "application/json")
			w.WriteHeader(http.StatusBadRequest)
			fmt.Fprintf(w, `{"error":"invalid JSON: %s"}`, err.Error())
			return
		}
	} else {
		payload = make(map[string]interface{})
	}

	// Inject action into body for temporal handler
	payload["action"] = action
	if _, ok := payload["namespace"]; !ok {
		payload["namespace"] = "default"
	}

	newBody, _ := json.Marshal(payload)
	r.Body = io.NopCloser(bytes.NewReader(newBody))
	r.ContentLength = int64(len(newBody))
	r.URL.Path = "/workflow"

	wa.temporalHandler.ServeHTTP(w, r)
}

// GetWorkflowSpec returns the ServiceAdapter spec for workflow service.
// This defines the available resources and methods.
func GetWorkflowSpec() *Spec {
	return &Spec{
		ServiceName: "workflow",
		Upstream: Upstream{
			URL:            "grpc://temporal:7233",
			TimeoutSeconds: 30,
		},
		Auth: Auth{
			Required:   true,
			Capability: "workflow:execute",
		},
		Retryable: true,
		Resources: []Resource{
			{
				Name: "execute",
				Methods: []Method{
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/StartWorkflowExecution",
						RequestSchema:  "workflow_start_request",
						ResponseSchema: "workflow_start_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:execute",
						},
					},
				},
			},
			{
				Name: "describe",
				Methods: []Method{
					{
						Verb:           "GET",
					},
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/DescribeWorkflowExecution",
						RequestSchema:  "workflow_describe_request",
						ResponseSchema: "workflow_describe_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:read",
						},
					},
				},
			},
			{
				Name: "list",
				Methods: []Method{
					{
						Verb:           "GET",
					},
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/ListWorkflowExecutions",
						RequestSchema:  "workflow_list_request",
						ResponseSchema: "workflow_list_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:read",
						},
					},
				},
			},
			{
				Name: "history",
				Methods: []Method{
					{
						Verb:           "GET",
					},
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/GetWorkflowExecutionHistory",
						RequestSchema:  "workflow_history_request",
						ResponseSchema: "workflow_history_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:read",
						},
					},
				},
			},
			{
				Name: "terminate",
				Methods: []Method{
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/TerminateWorkflowExecution",
						RequestSchema:  "workflow_terminate_request",
						ResponseSchema: "workflow_terminate_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:execute",
						},
					},
				},
			},
			{
				Name: "cancel",
				Methods: []Method{
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/RequestCancelWorkflowExecution",
						RequestSchema:  "workflow_cancel_request",
						ResponseSchema: "workflow_cancel_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:execute",
						},
					},
				},
			},
			{
				Name: "signal",
				Methods: []Method{
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/SignalWorkflowExecution",
						RequestSchema:  "workflow_signal_request",
						ResponseSchema: "workflow_signal_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:signal",
						},
					},
				},
			},
			{
				Name: "query",
				Methods: []Method{
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/QueryWorkflow",
						RequestSchema:  "workflow_query_request",
						ResponseSchema: "workflow_query_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:query",
						},
					},
				},
			},
			{
				Name: "reset",
				Methods: []Method{
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/ResetWorkflowExecution",
						RequestSchema:  "workflow_reset_request",
						ResponseSchema: "workflow_reset_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:execute",
						},
					},
				},
			},
			{
				Name: "update",
				Methods: []Method{
					{
						Verb:           "POST",
						UpstreamPath:   "/temporal.workflowservice.v1.WorkflowService/UpdateWorkflowExecution",
						RequestSchema:  "workflow_update_request",
						ResponseSchema: "workflow_update_response",
						Auth: &Auth{
							Required:   true,
							Capability: "workflow:execute",
						},
					},
				},
			},
		},
	}
}