agent: first pass at local service and check persistence

command/agent/agent.go

@@ -1,6 +1,7 @@
 package agent
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"log"
@@ -15,6 +16,14 @@ import (
 	"github.com/hashicorp/serf/serf"
 )
 
+const (
+	// Path to save agent service definitions
+	servicesDir = "services"
+
+	// Path to save local agent checks
+	checksDir = "checks"
+)
+
 /*
  The agent is the long running process that is run on every machine.
  It exposes an RPC interface that is used by the CLI to control the
@@ -132,6 +141,14 @@ func Create(config *Config, logOutput io.Writer) (*Agent, error) {
 		return nil, err
 	}
 
+	// Load any persisted services and services
+	if err := agent.restoreServices(); err != nil {
+		return nil, err
+	}
+	if err := agent.restoreChecks(); err != nil {
+		return nil, err
+	}
+
 	// Start handling events
 	go agent.handleEvents()
 
@@ -472,6 +489,140 @@ func (a *Agent) ResumeSync() {
 	a.state.Resume()
 }
 
+// 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)
+	if _, err := os.Stat(svcPath); os.IsNotExist(err) {
+		encoded, err := json.Marshal(service)
+		if err != nil {
+			return nil
+		}
+		if err := os.MkdirAll(filepath.Dir(svcPath), 0700); err != nil {
+			return err
+		}
+		fh, err := os.OpenFile(svcPath, os.O_CREATE|os.O_WRONLY, 0600)
+		if err != nil {
+			return err
+		}
+		defer fh.Close()
+		if _, err := fh.Write(encoded); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// 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)
+	if _, err := os.Stat(svcPath); err == nil {
+		return os.Remove(svcPath)
+	}
+	return nil
+}
+
+// restoreServices is used to load previously persisted service definitions
+// into the agent during startup.
+func (a *Agent) restoreServices() error {
+	svcDir := filepath.Join(a.config.DataDir, servicesDir)
+	if _, err := os.Stat(svcDir); os.IsNotExist(err) {
+		return nil
+	}
+
+	err := filepath.Walk(svcDir, func(path string, fi os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if fi.Name() == servicesDir {
+			return nil
+		}
+		fh, err := os.Open(filepath.Join(svcDir, fi.Name()))
+		if err != nil {
+			return err
+		}
+		content := make([]byte, fi.Size())
+		if _, err := fh.Read(content); err != nil {
+			return err
+		}
+
+		var svc *structs.NodeService
+		if err := json.Unmarshal(content, &svc); err != nil {
+			return err
+		}
+
+		a.logger.Printf("[DEBUG] Restored service definition: %s", svc.ID)
+		return a.AddService(svc, nil)
+	})
+	return err
+}
+
+// persistCheck saves a check definition to the local agent's state directory
+func (a *Agent) persistCheck(check *structs.HealthCheck) error {
+	checkPath := filepath.Join(a.config.DataDir, checksDir, check.CheckID)
+	if _, err := os.Stat(checkPath); os.IsNotExist(err) {
+		encoded, err := json.Marshal(check)
+		if err != nil {
+			return nil
+		}
+		if err := os.MkdirAll(filepath.Dir(checkPath), 0700); err != nil {
+			return err
+		}
+		fh, err := os.OpenFile(checkPath, os.O_CREATE|os.O_WRONLY, 0600)
+		if err != nil {
+			return err
+		}
+		defer fh.Close()
+		if _, err := fh.Write(encoded); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// 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)
+	if _, err := os.Stat(checkPath); err == nil {
+		return os.Remove(checkPath)
+	}
+	return nil
+}
+
+// restoreChecks is used to load previously persisted health check definitions
+// into the agent during startup.
+func (a *Agent) restoreChecks() error {
+	checkDir := filepath.Join(a.config.DataDir, checksDir)
+	if _, err := os.Stat(checkDir); os.IsNotExist(err) {
+		return nil
+	}
+
+	err := filepath.Walk(checkDir, func(path string, fi os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if fi.Name() == checksDir {
+			return nil
+		}
+		fh, err := os.Open(filepath.Join(checkDir, fi.Name()))
+		if err != nil {
+			return err
+		}
+		content := make([]byte, fi.Size())
+		if _, err := fh.Read(content); err != nil {
+			return err
+		}
+
+		var check *structs.HealthCheck
+		if err := json.Unmarshal(content, &check); err != nil {
+			return err
+		}
+
+		a.logger.Printf("[DEBUG] Restored health check: %s", check.CheckID)
+		return a.AddCheck(check, nil)
+	})
+	return err
+}
+
 // AddService is used to add a service entry.
 // This entry is persistent and the agent will make a best effort to
 // ensure it is registered
@@ -489,6 +640,9 @@ func (a *Agent) AddService(service *structs.NodeService, chkType *CheckType) err
 	// Add the service
 	a.state.AddService(service)
 
+	// Persist the service to a file
+	a.persistService(service)
+
 	// Create an associated health check
 	if chkType != nil {
 		check := &structs.HealthCheck{
@@ -520,6 +674,11 @@ func (a *Agent) RemoveService(serviceID string) error {
 	// Remove service immeidately
 	a.state.RemoveService(serviceID)
 
+	// Remove the service from the data dir
+	if err := a.purgeService(serviceID); err != nil {
+		return err
+	}
+
 	// Deregister any associated health checks
 	checkID := fmt.Sprintf("service:%s", serviceID)
 	return a.RemoveCheck(checkID)
@@ -580,7 +739,9 @@ func (a *Agent) AddCheck(check *structs.HealthCheck, chkType *CheckType) error {
 
 	// Add to the local state for anti-entropy
 	a.state.AddCheck(check)
-	return nil
+
+	// Persist the check
+	return a.persistCheck(check)
 }
 
 // RemoveCheck is used to remove a health check.
@@ -601,7 +762,7 @@ func (a *Agent) RemoveCheck(checkID string) error {
 		check.Stop()
 		delete(a.checkTTLs, checkID)
 	}
-	return nil
+	return a.purgeCheck(checkID)
 }
 
 // UpdateCheck is used to update the status of a check.

command/agent/agent_test.go

@@ -1,6 +1,8 @@
 package agent
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -380,3 +382,113 @@ func TestAgent_ConsulService(t *testing.T) {
 		t.Fatalf("%s service should be in sync", consul.ConsulServiceID)
 	}
 }
+
+func TestAgent_PersistService(t *testing.T) {
+	config := nextConfig()
+	dir, agent := makeAgent(t, config)
+	defer os.RemoveAll(dir)
+
+	svc := &structs.NodeService{
+		ID:      "redis",
+		Service: "redis",
+		Tags:    []string{"foo"},
+		Port:    8000,
+	}
+
+	if err := agent.AddService(svc, nil); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	file := filepath.Join(agent.config.DataDir, servicesDir, svc.ID)
+	if _, err := os.Stat(file); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	expected, err := json.Marshal(svc)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	content, err := ioutil.ReadFile(file)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if !bytes.Equal(expected, content) {
+		t.Fatalf("bad: %s", string(content))
+	}
+	agent.Shutdown()
+
+	// Should load it back during later start
+	agent2, err := Create(config, nil)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	defer agent2.Shutdown()
+
+	if _, ok := agent2.state.services[svc.ID]; !ok {
+		t.Fatalf("bad: %#v", agent2.state.services)
+	}
+
+	// Should remove the service file
+	if err := agent2.RemoveService(svc.ID); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if _, err := os.Stat(file); !os.IsNotExist(err) {
+		t.Fatalf("err: %s", err)
+	}
+}
+
+func TestAgent_PersistCheck(t *testing.T) {
+	config := nextConfig()
+	dir, agent := makeAgent(t, config)
+	defer os.RemoveAll(dir)
+
+	check := &structs.HealthCheck{
+		Node:        config.NodeName,
+		CheckID:     "service:redis1",
+		Name:        "redischeck",
+		Status:      structs.HealthPassing,
+		ServiceID:   "redis",
+		ServiceName: "redis",
+	}
+
+	if err := agent.AddCheck(check, nil); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	file := filepath.Join(agent.config.DataDir, checksDir, check.CheckID)
+	if _, err := os.Stat(file); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	expected, err := json.Marshal(check)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	content, err := ioutil.ReadFile(file)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if !bytes.Equal(expected, content) {
+		t.Fatalf("bad: %s", string(content))
+	}
+	agent.Shutdown()
+
+	// Should load it back during later start
+	agent2, err := Create(config, nil)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	defer agent2.Shutdown()
+
+	if _, ok := agent2.state.checks[check.CheckID]; !ok {
+		t.Fatalf("bad: %#v", agent2.state.checks)
+	}
+
+	// Should remove the service file
+	if err := agent2.RemoveCheck(check.CheckID); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if _, err := os.Stat(file); !os.IsNotExist(err) {
+		t.Fatalf("err: %s", err)
+	}
+}