add POST /shutdown-gracefully endpoint

jobs/nats-tls/spec

@@ -40,6 +40,7 @@ provides:
   - nats.cluster_port
   - nats.external.tls.ca
   - nats.write_deadline
+  - nats.migrate_server.port
 
 consumes:
 - name: nats

jobs/nats/spec

@@ -39,6 +39,10 @@ provides:
   - nats.cluster_port
   - nats.write_deadline
   - nats.disable
+  - nats.migrate_server.port
+  - nats.migrate_server.tls.ca:
+  - nats.migrate_server.tls.certificate:
+  - nats.migrate_server.tls.private_key:
 
 consumes:
 - name: nats

src/code.cloudfoundry.org/nats-v2-migrate/integration/nats_wrapper_test.go

@@ -16,6 +16,7 @@ import (
 
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
+	"github.com/onsi/gomega/gbytes"
 	"github.com/onsi/gomega/gexec"
 
 	"code.cloudfoundry.org/cf-networking-helpers/certauthority"
@@ -448,6 +449,35 @@ var _ = Describe("NATS Wrapper", func() {
 			})
 		})
 	})
+
+	Describe("/shutdown-gracefully", func() {
+
+		BeforeEach(func() {
+			cfg = config.Config{
+				Bootstrap:          true,
+				NATSMigratePort:    int(natsMigratorPort),
+				Address:            "127.0.0.1",
+				NATSPort:           int(natsPort),
+				NATSInstances:      []string{},
+				NATSMigrateServers: []string{},
+				NATSV1BinPath:      natsV1File,
+				NATSV2BinPath:      natsV2File,
+			}
+			GenerateCerts(&cfg)
+			StartServer(cfg)
+			client = CreateTLSClient(cfg)
+		})
+
+		It("sends a signal to NATS to shutdown", func() {
+			resp, err := client.Post(fmt.Sprintf("https://%s/shutdown-gracefully", address), "application/json", nil)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(resp.StatusCode).To(Equal(200))
+			Eventually(session).Should(gbytes.Say("graceful-shutdown-triggered"))
+			Eventually(session).Should(gbytes.Say("signalled-nats"))
+			// the nats in this test is fake so it doesn't actually exit
+			// which means that wrapper doesn't shut down in this test
+		})
+	})
 })
 
 func VerifyTCPConnection(address string) error {

src/code.cloudfoundry.org/nats-v2-migrate/nats-wrapper/main.go

@@ -68,6 +68,14 @@ func main() {
 	sm := http.NewServeMux()
 	sm.HandleFunc("/info", httpServer.Info)
 	sm.HandleFunc("/migrate", httpServer.Migrate)
+	sm.HandleFunc("POST /shutdown-gracefully", func(w http.ResponseWriter, r *http.Request) {
+		logger.Info("graceful-shutdown-triggered")
+		w.WriteHeader(http.StatusOK)
+		// #nosec G104 - don't handle error writing http response. at best, we could log it and be susceptible to DoS's filling up disks with logs
+		w.Write(nil)
+		syscall.Kill(os.Getpid(), syscall.SIGINT) // SIGINT stops the nats server gracefully
+		return
+	})
 
 	migrateServer := http_server.NewTLSServer(fmt.Sprintf("0.0.0.0:%d", cfg.NATSMigratePort), sm, tlsConfig)