agent: persist service/check data using hashed service/check IDs (fixes #573)

command/agent/agent.go

@@ -491,7 +491,7 @@ func (a *Agent) ResumeSync() {
 
 // persistService saves a service definition to a JSON file in the data dir
 func (a *Agent) persistService(service *structs.NodeService) error {
-	svcPath := filepath.Join(a.config.DataDir, servicesDir, service.ID)
+	svcPath := filepath.Join(a.config.DataDir, servicesDir, stringHash(service.ID))
 	if _, err := os.Stat(svcPath); os.IsNotExist(err) {
 		encoded, err := json.Marshal(service)
 		if err != nil {
@@ -514,7 +514,7 @@ func (a *Agent) persistService(service *structs.NodeService) error {
 
 // purgeService removes a persisted service definition file from the data dir
 func (a *Agent) purgeService(serviceID string) error {
-	svcPath := filepath.Join(a.config.DataDir, servicesDir, serviceID)
+	svcPath := filepath.Join(a.config.DataDir, servicesDir, stringHash(serviceID))
 	if _, err := os.Stat(svcPath); err == nil {
 		return os.Remove(svcPath)
 	}
@@ -565,7 +565,7 @@ func (a *Agent) restoreServices() error {
 
 // persistCheck saves a check definition to the local agent's state directory
 func (a *Agent) persistCheck(check *structs.HealthCheck, chkType *CheckType) error {
-	checkPath := filepath.Join(a.config.DataDir, checksDir, check.CheckID)
+	checkPath := filepath.Join(a.config.DataDir, checksDir, stringHash(check.CheckID))
 	if _, err := os.Stat(checkPath); !os.IsNotExist(err) {
 		return err
 	}
@@ -593,7 +593,7 @@ func (a *Agent) persistCheck(check *structs.HealthCheck, chkType *CheckType) err
 
 // purgeCheck removes a persisted check definition file from the data dir
 func (a *Agent) purgeCheck(checkID string) error {
-	checkPath := filepath.Join(a.config.DataDir, checksDir, checkID)
+	checkPath := filepath.Join(a.config.DataDir, checksDir, stringHash(checkID))
 	if _, err := os.Stat(checkPath); err == nil {
 		return os.Remove(checkPath)
 	}

command/agent/agent_test.go

@@ -398,7 +398,7 @@ func TestAgent_PersistService(t *testing.T) {
 		Port:    8000,
 	}
 
-	file := filepath.Join(agent.config.DataDir, servicesDir, svc.ID)
+	file := filepath.Join(agent.config.DataDir, servicesDir, stringHash(svc.ID))
 
 	// Check is not persisted unless requested
 	if err := agent.AddService(svc, nil, false); err != nil {
@@ -455,7 +455,7 @@ func TestAgent_PurgeService(t *testing.T) {
 		Port:    8000,
 	}
 
-	file := filepath.Join(agent.config.DataDir, servicesDir, svc.ID)
+	file := filepath.Join(agent.config.DataDir, servicesDir, stringHash(svc.ID))
 	if err := agent.AddService(svc, nil, true); err != nil {
 		t.Fatalf("err: %v", err)
 	}
@@ -513,7 +513,7 @@ func TestAgent_PurgeServiceOnDuplicate(t *testing.T) {
 	}
 	defer agent2.Shutdown()
 
-	file := filepath.Join(agent.config.DataDir, servicesDir, svc1.ID)
+	file := filepath.Join(agent.config.DataDir, servicesDir, stringHash(svc1.ID))
 	if _, err := os.Stat(file); err == nil {
 		t.Fatalf("should have removed persisted service")
 	}
@@ -546,7 +546,7 @@ func TestAgent_PersistCheck(t *testing.T) {
 		Interval: 10 * time.Second,
 	}
 
-	file := filepath.Join(agent.config.DataDir, checksDir, check.CheckID)
+	file := filepath.Join(agent.config.DataDir, checksDir, stringHash(check.CheckID))
 
 	// Not persisted if not requested
 	if err := agent.AddCheck(check, chkType, false); err != nil {
@@ -615,7 +615,7 @@ func TestAgent_PurgeCheck(t *testing.T) {
 		ServiceName: "redis",
 	}
 
-	file := filepath.Join(agent.config.DataDir, checksDir, check.CheckID)
+	file := filepath.Join(agent.config.DataDir, checksDir, stringHash(check.CheckID))
 	if err := agent.AddCheck(check, nil, true); err != nil {
 		t.Fatalf("err: %v", err)
 	}
@@ -677,7 +677,7 @@ func TestAgent_PurgeCheckOnDuplicate(t *testing.T) {
 	}
 	defer agent2.Shutdown()
 
-	file := filepath.Join(agent.config.DataDir, checksDir, check1.CheckID)
+	file := filepath.Join(agent.config.DataDir, checksDir, stringHash(check1.CheckID))
 	if _, err := os.Stat(file); err == nil {
 		t.Fatalf("should have removed persisted check")
 	}

command/agent/util.go

@@ -2,6 +2,7 @@ package agent
 
 import (
 	"bytes"
+	"crypto/md5"
 	crand "crypto/rand"
 	"fmt"
 	"math"
@@ -91,3 +92,8 @@ func encodeMsgPack(msg interface{}) ([]byte, error) {
 	err := codec.NewEncoder(&buf, msgpackHandle).Encode(msg)
 	return buf.Bytes(), err
 }
+
+// stringHash returns a simple md5sum for a string.
+func stringHash(s string) string {
+	return fmt.Sprintf("%x", md5.Sum([]byte(s)))
+}

command/agent/util_test.go

@@ -30,3 +30,12 @@ func TestRandomStagger(t *testing.T) {
 		}
 	}
 }
+
+func TestStringHash(t *testing.T) {
+	in := "hello world"
+	expected := "5eb63bbbe01eeed093cb22bb8f5acdc3"
+
+	if out := stringHash(in); out != expected {
+		t.Fatalf("bad: %s", out)
+	}
+}