server: shutdown endpoint (#466)

fixes #390

api/server/server.go

@@ -33,7 +33,7 @@ type Server struct {
 	singleflight singleflight // singleflight assists Datastore
 }
 
-func New(ctx context.Context, ds models.Datastore, mq models.MessageQueue, r *runner.Runner, tasks chan task.Request, enqueue models.Enqueue) *Server {
+func New(ctx context.Context, ds models.Datastore, mq models.MessageQueue, r *runner.Runner, tasks chan task.Request, enqueue models.Enqueue, opts ...ServerOption) *Server {
 	s := &Server{
 		Runner:    r,
 		Router:    gin.New(),
@@ -45,6 +45,10 @@ func New(ctx context.Context, ds models.Datastore, mq models.MessageQueue, r *ru
 
 	s.Router.Use(prepareMiddleware(ctx))
 
+	for _, opt := range opts {
+		opt(s)
+	}
+
 	return s
 }
 

api/server/server_options.go

@@ -0,0 +1,11 @@
+package server
+
+import "context"
+
+type ServerOption func(*Server)
+
+func EnableShutdownEndpoint(halt context.CancelFunc) ServerOption {
+	return func(s *Server) {
+		s.Router.GET("/shutdown", s.handleShutdown(halt))
+	}
+}

api/server/shutdown.go

@@ -0,0 +1,15 @@
+package server
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+func (s *Server) handleShutdown(halt context.CancelFunc) func(*gin.Context) {
+	return func(c *gin.Context) {
+		halt()
+		c.JSON(http.StatusOK, "shutting down")
+	}
+}

api/server/special_handler_test.go

@@ -2,12 +2,13 @@ package server
 
 import (
 	"context"
+	"testing"
+
 	"github.com/iron-io/functions/api/datastore"
 	"github.com/iron-io/functions/api/models"
 	"github.com/iron-io/functions/api/mqs"
 	"github.com/iron-io/functions/api/runner"
 	"github.com/iron-io/functions/api/runner/task"
-	"testing"
 )
 
 type testSpecialHandler struct{}

main.go

@@ -92,7 +92,15 @@ func main() {
 	})
 
 	svr.AddFunc(func(ctx context.Context) {
-		srv := server.New(ctx, ds, mq, rnr, tasks, server.DefaultEnqueue)
+		srv := server.New(
+			ctx,
+			ds,
+			mq,
+			rnr,
+			tasks,
+			server.DefaultEnqueue,
+			server.EnableShutdownEndpoint(halt),
+		)
 		srv.Run()
 		<-ctx.Done()
 	})