agent/proxy: manager and basic tests, not great coverage yet coming soon

agent/agent.go

@@ -2038,6 +2038,7 @@ func (a *Agent) AddProxy(proxy *structs.ConnectManagedProxy, persist bool) error
 	// Lookup the target service token in state if there is one.
 	token := a.State.ServiceToken(proxy.TargetServiceID)
 
+	/*
 		// Determine if we need to default the command
 		if proxy.ExecMode == structs.ProxyExecModeDaemon && len(proxy.Command) == 0 {
 			// We use the globally configured default command. If it is empty
@@ -2053,43 +2054,22 @@ func (a *Agent) AddProxy(proxy *structs.ConnectManagedProxy, persist bool) error
 
 			proxy.CommandDefault = cmd
 		}
+	*/
 
 	// Add the proxy to local state first since we may need to assign a port which
 	// needs to be coordinate under state lock. AddProxy will generate the
 	// NodeService for the proxy populated with the allocated (or configured) port
 	// and an ID, but it doesn't add it to the agent directly since that could
 	// deadlock and we may need to coordinate adding it and persisting etc.
-	proxyState, oldProxy, err := a.State.AddProxy(proxy, token)
+	proxyState, err := a.State.AddProxy(proxy, token)
 	if err != nil {
 		return err
 	}
 	proxyService := proxyState.Proxy.ProxyService
 
-	// If we replaced an existing proxy, stop that process.
-	if oldProxy != nil {
-		if err := oldProxy.ProxyProcess.Stop(); err != nil {
-			a.logger.Printf(
-				"[ERR] error stopping managed proxy, may still be running: %s",
-				err)
-		}
-	}
-
-	// Start the proxy process
-	if err := proxyState.ProxyProcess.Start(); err != nil {
-		a.State.RemoveProxy(proxyService.ID)
-		return fmt.Errorf("error starting managed proxy: %s", err)
-	}
-
 	// TODO(banks): register proxy health checks.
 	err = a.AddService(proxyService, nil, persist, token)
 	if err != nil {
-		// Stop the proxy process if it was started
-		if err := proxyState.ProxyProcess.Stop(); err != nil {
-			a.logger.Printf(
-				"[ERR] error stopping managed proxy, may still be running: %s",
-				err)
-		}
-
 		// Remove the state too
 		a.State.RemoveProxy(proxyService.ID)
 		return err
@@ -2107,18 +2087,10 @@ func (a *Agent) RemoveProxy(proxyID string, persist bool) error {
 	}
 
 	// Remove the proxy from the local state
-	proxyState, err := a.State.RemoveProxy(proxyID)
+	if _, err := a.State.RemoveProxy(proxyID); err != nil {
-	if err != nil {
 		return err
 	}
 
-	// Stop the process. The proxy implementation is expected to perform
-	// retries so if this fails then retries have already been performed and
-	// the most we can do is just error.
-	if err := proxyState.ProxyProcess.Stop(); err != nil {
-		return fmt.Errorf("error stopping managed proxy process: %s", err)
-	}
-
 	// TODO(banks): unpersist proxy
 
 	return nil

agent/local/testing.go

@@ -0,0 +1,19 @@
+package local
+
+import (
+	"log"
+	"os"
+
+	"github.com/hashicorp/consul/agent/token"
+	"github.com/mitchellh/go-testing-interface"
+)
+
+// TestState returns a configured *State for testing.
+func TestState(t testing.T) *State {
+	result := NewState(Config{
+		ProxyBindMinPort: 20000,
+		ProxyBindMaxPort: 20500,
+	}, log.New(os.Stderr, "", log.LstdFlags), &token.Store{})
+	result.TriggerSyncChanges = func() {}
+	return result
+}

agent/proxy/daemon_test.go

@@ -16,6 +16,8 @@ func TestDaemon_impl(t *testing.T) {
 }
 
 func TestDaemonStartStop(t *testing.T) {
+	t.Parallel()
+
 	require := require.New(t)
 	td, closer := testTempDir(t)
 	defer closer()
@@ -63,6 +65,8 @@ func TestDaemonStartStop(t *testing.T) {
 }
 
 func TestDaemonRestart(t *testing.T) {
+	t.Parallel()
+
 	require := require.New(t)
 	td, closer := testTempDir(t)
 	defer closer()

agent/proxy/manager.go

@@ -0,0 +1,300 @@
+package proxy
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"sync"
+
+	"github.com/hashicorp/consul/agent/local"
+	"github.com/hashicorp/consul/agent/structs"
+	"github.com/hashicorp/go-multierror"
+)
+
+// Manager starts, stops, snapshots, and restores managed proxies.
+//
+// The manager will not start or stop any processes until Start is called.
+// Prior to this, any configuration, snapshot loading, etc. can be done.
+// Even if a process is no longer running after loading the snapshot, it
+// will not be restarted until Start is called.
+//
+// The Manager works by subscribing to change notifications on a local.State
+// structure. Whenever a change is detected, the Manager syncs its internal
+// state with the local.State and starts/stops any necessary proxies. The
+// manager never holds a lock on local.State (except to read the proxies)
+// and state updates may occur while the Manger is syncing. This is okay,
+// since a change notification will be queued to trigger another sync.
+//
+// NOTE(mitchellh): Change notifications are not coalesced currently. Under
+// conditions where managed proxy configurations are changing in a hot
+// loop, it is possible for the manager to constantly attempt to sync. This
+// is unlikely, but its also easy to introduce basic coalescing (even over
+// millisecond intervals) to prevent total waste compute cycles.
+type Manager struct {
+	// State is the local state that is the source of truth for all
+	// configured managed proxies.
+	State *local.State
+
+	// Logger is the logger for information about manager behavior.
+	// Output for proxies will not go here generally but varies by proxy
+	// implementation type.
+	Logger *log.Logger
+
+	// lock is held while reading/writing any internal state of the manager.
+	// cond is a condition variable on lock that is broadcasted for runState
+	// changes.
+	lock *sync.Mutex
+	cond *sync.Cond
+
+	// runState is the current state of the manager. To read this the
+	// lock must be held. The condition variable cond can be waited on
+	// for changes to this value.
+	runState managerRunState
+
+	proxies map[string]Proxy
+}
+
+// defaultLogger is the defaultLogger for NewManager so there it is never nil
+var defaultLogger = log.New(os.Stderr, "", log.LstdFlags)
+
+// NewManager initializes a Manager. After initialization, the exported
+// fields should be configured as desired. To start the Manager, execute
+// Run in a goroutine.
+func NewManager() *Manager {
+	var lock sync.Mutex
+	return &Manager{
+		Logger:  defaultLogger,
+		lock:    &lock,
+		cond:    sync.NewCond(&lock),
+		proxies: make(map[string]Proxy),
+	}
+}
+
+// managerRunState is the state of the Manager.
+//
+// This is a basic state machine with the following transitions:
+//
+//   * idle     => running, stopped
+//   * running  => stopping, stopped
+//   * stopping => stopped
+//   * stopped  => <>
+//
+type managerRunState uint8
+
+const (
+	managerStateIdle managerRunState = iota
+	managerStateRunning
+	managerStateStopping
+	managerStateStopped
+)
+
+// Close stops the manager. Managed processes are NOT stopped.
+func (m *Manager) Close() error {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	for {
+		switch m.runState {
+		case managerStateIdle:
+			// Idle so just set it to stopped and return. We notify
+			// the condition variable in case others are waiting.
+			m.runState = managerStateStopped
+			m.cond.Broadcast()
+			return nil
+
+		case managerStateRunning:
+			// Set the state to stopping and broadcast to all waiters,
+			// since Run is sitting on cond.Wait.
+			m.runState = managerStateStopping
+			m.cond.Broadcast()
+			m.cond.Wait() // Wait on the stopping event
+
+		case managerStateStopping:
+			// Still stopping, wait...
+			m.cond.Wait()
+
+		case managerStateStopped:
+			// Stopped, target state reached
+			return nil
+		}
+	}
+}
+
+// Kill will Close the manager and Kill all proxies that were being managed.
+//
+// This is safe to call with Close already called since Close is idempotent.
+func (m *Manager) Kill() error {
+	// Close first so that we aren't getting changes in proxies
+	if err := m.Close(); err != nil {
+		return err
+	}
+
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	var err error
+	for id, proxy := range m.proxies {
+		if err := proxy.Stop(); err != nil {
+			err = multierror.Append(
+				err, fmt.Errorf("failed to stop proxy %q: %s", id, err))
+			continue
+		}
+
+		// Remove it since it is already stopped successfully
+		delete(m.proxies, id)
+	}
+
+	return err
+}
+
+// Run syncs with the local state and supervises existing proxies.
+//
+// This blocks and should be run in a goroutine. If another Run is already
+// executing, this will do nothing and return.
+func (m *Manager) Run() {
+	m.lock.Lock()
+	if m.runState != managerStateIdle {
+		m.lock.Unlock()
+		return
+	}
+
+	// Set the state to running
+	m.runState = managerStateRunning
+	m.lock.Unlock()
+
+	// Start a goroutine that just waits for a stop request
+	stopCh := make(chan struct{})
+	go func() {
+		defer close(stopCh)
+		m.lock.Lock()
+		defer m.lock.Unlock()
+
+		// We wait for anything not running, just so we're more resilient
+		// in the face of state machine issues. Basically any state change
+		// will cause us to quit.
+		for m.runState != managerStateRunning {
+			m.cond.Wait()
+		}
+	}()
+
+	// When we exit, we set the state to stopped and broadcast to any
+	// waiting Close functions that they can return.
+	defer func() {
+		m.lock.Lock()
+		m.runState = managerStateStopped
+		m.cond.Broadcast()
+		m.lock.Unlock()
+	}()
+
+	// Register for proxy catalog change notifications
+	notifyCh := make(chan struct{}, 1)
+	m.State.NotifyProxy(notifyCh)
+	defer m.State.StopNotifyProxy(notifyCh)
+
+	for {
+		// Sync first, before waiting on further notifications so that
+		// we can start with a known-current state.
+		m.sync()
+
+		select {
+		case <-notifyCh:
+			// Changes exit select so we can reloop and reconfigure proxies
+
+		case <-stopCh:
+			// Stop immediately, no cleanup
+			return
+		}
+	}
+}
+
+// sync syncs data with the local state store to update the current manager
+// state and start/stop necessary proxies.
+func (m *Manager) sync() {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	// Get the current set of proxies
+	state := m.State.Proxies()
+
+	// Go through our existing proxies that we're currently managing to
+	// determine if they're still in the state or not. If they're in the
+	// state, we need to diff to determine if we're starting a new proxy
+	// If they're not in the state, then we need to stop the proxy since it
+	// is now orphaned.
+	for id, proxy := range m.proxies {
+		// Get the proxy.
+		stateProxy, ok := state[id]
+		if !ok {
+			// Proxy is deregistered. Remove it from our map and stop it
+			delete(m.proxies, id)
+			if err := proxy.Stop(); err != nil {
+				m.Logger.Printf("[ERROR] agent/proxy: failed to stop deregistered proxy for %q: %s", id, err)
+			}
+
+			continue
+		}
+
+		// Proxy is in the state. Always delete it so that the remainder
+		// are NEW proxies that we start after this loop.
+		delete(state, id)
+
+		// TODO: diff and restart if necessary
+		println(stateProxy)
+	}
+
+	// Remaining entries in state are new proxies. Start them!
+	for id, stateProxy := range state {
+		proxy, err := m.newProxy(stateProxy)
+		if err != nil {
+			m.Logger.Printf("[ERROR] agent/proxy: failed to initialize proxy for %q: %s", id, err)
+			continue
+		}
+
+		if err := proxy.Start(); err != nil {
+			m.Logger.Printf("[ERROR] agent/proxy: failed to start proxy for %q: %s", id, err)
+			continue
+		}
+
+		m.proxies[id] = proxy
+	}
+}
+
+// newProxy creates the proper Proxy implementation for the configured
+// local managed proxy.
+func (m *Manager) newProxy(mp *local.ManagedProxy) (Proxy, error) {
+	// Defensive because the alternative is to panic which is not desired
+	if mp == nil || mp.Proxy == nil {
+		return nil, fmt.Errorf("internal error: nil *local.ManagedProxy or Proxy field")
+	}
+
+	p := mp.Proxy
+	switch p.ExecMode {
+	case structs.ProxyExecModeDaemon:
+		command := p.Command
+		if len(command) == 0 {
+			command = p.CommandDefault
+		}
+
+		// This should never happen since validation should happen upstream
+		// but verify it because the alternative is to panic below.
+		if len(command) == 0 {
+			return nil, fmt.Errorf("daemon mode managed proxy requires command")
+		}
+
+		// Build the command to execute.
+		var cmd exec.Cmd
+		cmd.Path = command[0]
+		cmd.Args = command[1:]
+
+		// Build the daemon structure
+		return &Daemon{
+			Command:    &cmd,
+			ProxyToken: mp.ProxyToken,
+			Logger:     m.Logger,
+		}, nil
+
+	default:
+		return nil, fmt.Errorf("unsupported managed proxy type: %q", p.ExecMode)
+	}
+}

agent/proxy/manager_test.go

@@ -0,0 +1,79 @@
+package proxy
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+
+	"github.com/hashicorp/consul/agent/local"
+	"github.com/hashicorp/consul/agent/structs"
+	"github.com/hashicorp/consul/testutil/retry"
+	"github.com/stretchr/testify/require"
+)
+
+func TestManagerClose_noRun(t *testing.T) {
+	t.Parallel()
+
+	// Really we're testing that it doesn't deadlock here.
+	m := NewManager()
+	require.NoError(t, m.Close())
+
+	// Close again for sanity
+	require.NoError(t, m.Close())
+}
+
+// Test that Run performs an initial sync (if local.State is already set)
+// rather than waiting for a notification from the local state.
+func TestManagerRun_initialSync(t *testing.T) {
+	t.Parallel()
+
+	state := testState(t)
+	m := NewManager()
+	m.State = state
+	defer m.Kill()
+
+	// Add the proxy before we start the manager to verify initial sync
+	td, closer := testTempDir(t)
+	defer closer()
+	path := filepath.Join(td, "file")
+	testStateProxy(t, state, helperProcess("restart", path))
+
+	// Start the manager
+	go m.Run()
+
+	// We should see the path appear shortly
+	retry.Run(t, func(r *retry.R) {
+		_, err := os.Stat(path)
+		if err == nil {
+			return
+		}
+		r.Fatalf("error waiting for path: %s", err)
+	})
+}
+
+func testState(t *testing.T) *local.State {
+	state := local.TestState(t)
+	require.NoError(t, state.AddService(&structs.NodeService{
+		Service: "web",
+	}, "web"))
+
+	return state
+}
+
+// testStateProxy registers a proxy with the given local state and the command
+// (expected to be from the helperProcess function call). It returns the
+// ID for deregistration.
+func testStateProxy(t *testing.T, state *local.State, cmd *exec.Cmd) string {
+	command := []string{cmd.Path}
+	command = append(command, cmd.Args...)
+
+	p, err := state.AddProxy(&structs.ConnectManagedProxy{
+		ExecMode:        structs.ProxyExecModeDaemon,
+		Command:         command,
+		TargetServiceID: "web",
+	}, "web")
+	require.NoError(t, err)
+
+	return p.Proxy.ProxyService.ID
+}

agent/proxy/proxy_test.go

@@ -31,16 +31,19 @@ func testTempDir(t *testing.T) (string, func()) {
 	}
 }
 
+// helperProcessSentinel is a sentinel value that is put as the first
+// argument following "--" and is used to determine if TestHelperProcess
+// should run.
+const helperProcessSentinel = "WANT_HELPER_PROCESS"
+
 // helperProcess returns an *exec.Cmd that can be used to execute the
 // TestHelperProcess function below. This can be used to test multi-process
 // interactions.
 func helperProcess(s ...string) *exec.Cmd {
-	cs := []string{"-test.run=TestHelperProcess", "--"}
+	cs := []string{"-test.run=TestHelperProcess", "--", helperProcessSentinel}
 	cs = append(cs, s...)
-	env := []string{"GO_WANT_HELPER_PROCESS=1"}
 
 	cmd := exec.Command(os.Args[0], cs...)
-	cmd.Env = append(env, os.Environ()...)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	return cmd
@@ -49,12 +52,6 @@ func helperProcess(s ...string) *exec.Cmd {
 // This is not a real test. This is just a helper process kicked off by tests
 // using the helperProcess helper function.
 func TestHelperProcess(t *testing.T) {
-	if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" {
-		return
-	}
-
-	defer os.Exit(0)
-
 	args := os.Args
 	for len(args) > 0 {
 		if args[0] == "--" {
@@ -65,15 +62,16 @@ func TestHelperProcess(t *testing.T) {
 		args = args[1:]
 	}
 
-	if len(args) == 0 {
+	if len(args) == 0 || args[0] != helperProcessSentinel {
-		fmt.Fprintf(os.Stderr, "No command\n")
+		return
-		os.Exit(2)
 	}
 
+	defer os.Exit(0)
+	args = args[1:] // strip sentinel value
 	cmd, args := args[0], args[1:]
 	switch cmd {
 	// While running, this creates a file in the given directory (args[0])
-	// and deletes it only whe nit is stopped.
+	// and deletes it only when it is stopped.
 	case "start-stop":
 		ch := make(chan os.Signal, 1)
 		signal.Notify(ch, os.Interrupt)

agent/proxy/test.go

@@ -0,0 +1,13 @@
+package proxy
+
+// defaultTestProxy is the test proxy that is instantiated for proxies with
+// an execution mode of ProxyExecModeTest.
+var defaultTestProxy = testProxy{}
+
+// testProxy is a Proxy implementation that stores state in-memory and
+// is only used for unit testing. It is in a non _test.go file because the
+// factory for initializing it is exported (newProxy).
+type testProxy struct {
+	Start uint32
+	Stop  uint32
+}

agent/structs/connect.go

@@ -33,6 +33,11 @@ const (
 	// ProxyExecModeScript executes a proxy config script on each change to it's
 	// config.
 	ProxyExecModeScript
+
+	// ProxyExecModeTest tracks the start/stop of the proxy in-memory
+	// and is only used for tests. This shouldn't be set outside of tests,
+	// but even if it is it has no external effect.
+	ProxyExecModeTest
 )
 
 // String implements Stringer