Manual rollback after grace period

.mockery.yaml

@@ -5,6 +5,9 @@ filename: mocks.go
 template-data:
   unroll-variadic: true
 packages:
+  github.com/elastic/elastic-agent/internal/pkg/agent/application:
+    interfaces:
+      rollbacksSource: {}
   github.com/elastic/elastic-agent/internal/pkg/agent/application/actions/handlers:
     interfaces:
       Uploader: {}

internal/pkg/agent/application/application.go

@@ -7,11 +7,14 @@ package application
 import (
 	"context"
 	"fmt"
+	"os"
+	"path/filepath"
 	"time"
 
 	"go.elastic.co/apm/v2"
 
 	componentmonitoring "github.com/elastic/elastic-agent/internal/pkg/agent/application/monitoring/component"
+	"github.com/elastic/elastic-agent/internal/pkg/agent/install"
 
 	"github.com/elastic/go-ucfg"
 
@@ -48,6 +51,11 @@ import (
 	"github.com/elastic/elastic-agent/version"
 )
 
+type rollbacksSource interface {
+	Set(map[string]upgrade.TTLMarker) error
+	Get() (map[string]upgrade.TTLMarker, error)
+}
+
 // CfgOverrider allows for application driven overrides of configuration read from disk.
 type CfgOverrider func(cfg *configuration.Configuration)
 
@@ -131,6 +139,10 @@ func New(
 	isMonitoringSupported := !disableMonitoring && cfg.Settings.V1MonitoringEnabled
 
 	availableRollbacksSource := upgrade.NewTTLMarkerRegistry(log, paths.Top())
+	if platform.OS != component.Container {
+		// If we are not running in a container, check and normalize the install descriptor before we start the agent
+		normalizeInstallDescriptorAtStartup(log, paths.Top(), time.Now(), initialUpdateMarker, availableRollbacksSource)
+	}
 	upgrader, err := upgrade.NewUpgrader(log, cfg.Settings.DownloadConfig, cfg.Settings.Upgrade, agentInfo, new(upgrade.AgentWatcherHelper), availableRollbacksSource)
 	if err != nil {
 		return nil, nil, nil, fmt.Errorf("failed to create upgrader: %w", err)
@@ -296,6 +308,86 @@ func New(
 	return coord, configMgr, varsManager, nil
 }
 
+// normalizeInstallDescriptorAtStartup will check the install descriptor checking:
+// - if we just rolled back: the update marker is checked and in case of rollback we clean up the entry about the failed upgraded install
+// - check all the entries:
+//   - verify that the home directory for that install still exists (remove what does not exist anymore)
+//   - TODO check TTLs of installs to schedule delayed cleanup while the agent is running
+//
+// This function will NOT error out, it will log any errors it encounters as warnings but any error must be treated as non-fatal
+func normalizeInstallDescriptorAtStartup(log *logger.Logger, topDir string, now time.Time, initialUpdateMarker *upgrade.UpdateMarker, rollbackSource rollbacksSource) {
+	// Check if we rolled back and update the install descriptor
+	if initialUpdateMarker != nil && initialUpdateMarker.Details != nil && initialUpdateMarker.Details.State == details.StateRollback {
+		// Reset the TTL for the current version if we are coming off a rollback
+		rollbacks, err := rollbackSource.Get()
+		if err != nil {
+			log.Warnf("Error getting available rollbacks from rollbackSource during startup check: %s", err)
+			return
+		}
+
+		// remove the current versioned home TTL marker
+		delete(rollbacks, initialUpdateMarker.PrevVersionedHome)
+		err = rollbackSource.Set(rollbacks)
+		if err != nil {
+			log.Warnf("Error removing install descriptor from installDescriptorSource during startup check: %s", err)
+			return
+		}
+	}
+
+	// check if we need to cleanup old agent installs
+	rollbacks, err := rollbackSource.Get()
+	if err != nil {
+		log.Warnf("Error getting available rollbacks during startup check: %s", err)
+		return
+	}
+
+	var versionedHomesToCleanup []string
+	for versionedHome, ttlMarker := range rollbacks {
+
+		versionedHomeAbsPath := filepath.Join(topDir, versionedHome)
+
+		if versionedHomeAbsPath == paths.HomeFrom(topDir) {
+			// skip the current install
+			log.Warnf("Found a TTL marker for the currently running agent at %s. Skipping cleanup...", versionedHome)
+			continue
+		}
+
+		_, err = os.Stat(versionedHomeAbsPath)
+		if errors.Is(err, os.ErrNotExist) {
+			log.Warnf("Versioned home %s corresponding to agent install descriptor %+v  is not found on disk", versionedHomeAbsPath, ttlMarker)
+			versionedHomesToCleanup = append(versionedHomesToCleanup, versionedHome)
+			continue
+		}
+
+		if err != nil {
+			log.Warnf("error checking versioned home %s for agent install: %s", versionedHomeAbsPath, err.Error())
+			continue
+		}
+
+		if now.After(ttlMarker.ValidUntil) {
+			// the install directory exists but it's expired. Remove the files.
+			log.Infof("agent install descriptor %+v is expired, removing directory %q", ttlMarker, versionedHomeAbsPath)
+			if cleanupErr := install.RemoveBut(versionedHomeAbsPath, true); cleanupErr != nil {
+				log.Warnf("Error removing directory %q: %s", versionedHomeAbsPath, cleanupErr)
+			} else {
+				log.Infof("Directory %q was removed", versionedHomeAbsPath)
+				versionedHomesToCleanup = append(versionedHomesToCleanup, versionedHome)
+			}
+		}
+	}
+
+	if len(versionedHomesToCleanup) > 0 {
+		log.Infof("removing install descriptor(s) for %v", versionedHomesToCleanup)
+		for _, versionedHomeToCleanup := range versionedHomesToCleanup {
+			delete(rollbacks, versionedHomeToCleanup)
+		}
+		err = rollbackSource.Set(rollbacks)
+		if err != nil {
+			log.Warnf("Error removing install descriptor(s): %s", err)
+		}
+	}
+}
+
 func mergeFleetConfig(ctx context.Context, rawConfig *config.Config) (storage.Store, *configuration.Configuration, error) {
 	path := paths.AgentConfigFile()
 	store, err := storage.NewEncryptedDiskStore(ctx, path)

internal/pkg/agent/application/application_test.go

@@ -7,6 +7,9 @@ package application
 import (
 	"context"
 	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
 	"testing"
 	"time"
 
@@ -15,6 +18,9 @@ import (
 
 	"github.com/elastic/elastic-agent-libs/logp"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/info"
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/paths"
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade"
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
 	"github.com/elastic/elastic-agent/internal/pkg/config"
 	"github.com/elastic/elastic-agent/internal/pkg/testutils"
 	"github.com/elastic/elastic-agent/pkg/core/logger/loggertest"
@@ -302,3 +308,188 @@ func TestInjectOutputOverrides(t *testing.T) {
 		})
 	}
 }
+
+func Test_normalizeInstallDescriptorAtStartup(t *testing.T) {
+
+	now := time.Now()
+	tomorrow := now.Add(24 * time.Hour)
+	yesterday := now.Add(-24 * time.Hour)
+
+	tests := []struct {
+		name                    string
+		setup                   func(t *testing.T, topDir string) (*upgrade.UpdateMarker, rollbacksSource)
+		postNormalizeAssertions func(t *testing.T, topDir string, initialUpdateMarker *upgrade.UpdateMarker)
+	}{
+		{
+			name: "happy path: single install, no rollbacks, no modifications needed",
+			setup: func(t *testing.T, topDir string) (*upgrade.UpdateMarker, rollbacksSource) {
+				mockRollbackSource := newMockRollbacksSource(t)
+				mockRollbackSource.EXPECT().Get().Return(nil, nil)
+				return nil, mockRollbackSource
+			},
+
+			postNormalizeAssertions: nil,
+		},
+		{
+			name: "Agent was manually rolled back: rolled back install is removed from the list",
+			setup: func(t *testing.T, topDir string) (*upgrade.UpdateMarker, rollbacksSource) {
+				newAgentInstallPath := createFakeAgentInstall(t, topDir, "4.5.6", "newversionhash", true)
+				oldAgentInstallPath := createFakeAgentInstall(t, topDir, "1.2.3", "oldversionhash", true)
+
+				mockRollbackSource := newMockRollbacksSource(t)
+				mockRollbackSource.EXPECT().Get().Return(map[string]upgrade.TTLMarker{
+					oldAgentInstallPath: {
+						Version:    "1.2.3",
+						Hash:       "oldversionhash",
+						ValidUntil: tomorrow,
+					},
+				}, nil)
+
+				updateMarker := &upgrade.UpdateMarker{
+					Version:           "4.5.6",
+					Hash:              "newversionhash",
+					VersionedHome:     newAgentInstallPath,
+					UpdatedOn:         now,
+					PrevVersion:       "1.2.3",
+					PrevHash:          "oldversionhash",
+					PrevVersionedHome: oldAgentInstallPath,
+					Acked:             false,
+					Action:            nil,
+					Details: &details.Details{
+						TargetVersion: "4.5.6",
+						State:         details.StateRollback,
+						ActionID:      "",
+						Metadata: details.Metadata{
+							Reason: details.ReasonManualRollbackPattern,
+						},
+					},
+				}
+
+				// expect code to clear the rollback
+				mockRollbackSource.EXPECT().Set(map[string]upgrade.TTLMarker{}).Return(nil)
+				return updateMarker, mockRollbackSource
+			},
+			postNormalizeAssertions: nil,
+		},
+		{
+			name: "Entries not having a matching install directory will be removed from the list",
+			setup: func(t *testing.T, topDir string) (*upgrade.UpdateMarker, rollbacksSource) {
+				_ = createFakeAgentInstall(t, topDir, "4.5.6", "newversionhash", true)
+				oldAgentInstallPath := createFakeAgentInstall(t, topDir, "1.2.3", "oldversionhash", true)
+
+				mockRollbackSource := newMockRollbacksSource(t)
+				nonExistingVersionedHome := filepath.Join("data", "thisdirectorydoesnotexist")
+				mockRollbackSource.EXPECT().Get().Return(map[string]upgrade.TTLMarker{
+					oldAgentInstallPath: {
+						Version:    "1.2.3",
+						Hash:       "oldversionhash",
+						ValidUntil: tomorrow,
+					},
+					nonExistingVersionedHome: {
+						Version:    "0.0.0",
+						Hash:       "nonExistingHash",
+						ValidUntil: tomorrow,
+					},
+				}, nil)
+
+				mockRollbackSource.EXPECT().Set(map[string]upgrade.TTLMarker{
+					oldAgentInstallPath: {
+						Version:    "1.2.3",
+						Hash:       "oldversionhash",
+						ValidUntil: tomorrow,
+					},
+				}).Return(nil)
+				return nil, mockRollbackSource
+			},
+			postNormalizeAssertions: nil,
+		},
+		{
+			name: "Expired installs still existing on disk will be removed from the install list and removed from disk",
+			setup: func(t *testing.T, topDir string) (*upgrade.UpdateMarker, rollbacksSource) {
+				_ = createFakeAgentInstall(t, topDir, "4.5.6", "newversionhash", true)
+				oldAgentInstallPath := createFakeAgentInstall(t, topDir, "1.2.3", "oldversionhash", true)
+
+				// assert that the versionedHome of the old install is the same we check in postNormalizeAssertions
+				assert.Equal(t, oldAgentInstallPath, filepath.Join("data", "elastic-agent-1.2.3-oldver"),
+					"Unexpected old install versioned home. Post normalize assertions may not be working")
+
+				mockRollbackSource := newMockRollbacksSource(t)
+				mockRollbackSource.EXPECT().Get().Return(
+					map[string]upgrade.TTLMarker{
+						oldAgentInstallPath: {
+							Version:    "1.2.3",
+							Hash:       "oldver",
+							ValidUntil: yesterday,
+						},
+					},
+					nil,
+				)
+				// expect removal of the existing ttlmarker
+				mockRollbackSource.EXPECT().Set(map[string]upgrade.TTLMarker{}).Return(nil)
+				return nil, mockRollbackSource
+			},
+			postNormalizeAssertions: func(t *testing.T, topDir string, _ *upgrade.UpdateMarker) {
+				assert.NoDirExists(t, filepath.Join(topDir, "data", "elastic-agent-1.2.3-oldver"))
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			logger, _ := loggertest.New(t.Name())
+			tmpDir := t.TempDir()
+			updateMarker, installSource := tt.setup(t, tmpDir)
+			normalizeInstallDescriptorAtStartup(logger, tmpDir, now, updateMarker, installSource)
+			if tt.postNormalizeAssertions != nil {
+				tt.postNormalizeAssertions(t, tmpDir, updateMarker)
+			}
+		})
+	}
+}
+
+// createFakeAgentInstall (copied from the upgrade package tests) will create a mock agent install within topDir, possibly
+// using the version in the directory name, depending on useVersionInPath it MUST return the path to the created versionedHome
+// relative to topDir, to mirror what step_unpack returns
+func createFakeAgentInstall(t *testing.T, topDir, version, hash string, useVersionInPath bool) string {
+
+	// create versioned home
+	versionedHome := fmt.Sprintf("elastic-agent-%s", hash[:upgrade.HashLen])
+	if useVersionInPath {
+		// use the version passed as parameter
+		versionedHome = fmt.Sprintf("elastic-agent-%s-%s", version, hash[:upgrade.HashLen])
+	}
+	relVersionedHomePath := filepath.Join("data", versionedHome)
+	absVersionedHomePath := filepath.Join(topDir, relVersionedHomePath)
+
+	// recalculate the binary path and launch a mkDirAll to account for MacOS weirdness
+	// (the extra nesting of elastic agent binary within versionedHome)
+	absVersioneHomeBinaryPath := paths.BinaryPath(absVersionedHomePath, "")
+	err := os.MkdirAll(absVersioneHomeBinaryPath, 0o750)
+	require.NoError(t, err, "error creating fake install versioned home directory (including binary path) %q", absVersioneHomeBinaryPath)
+
+	// place a few directories in the fake install
+	absComponentsDirPath := filepath.Join(absVersionedHomePath, "components")
+	err = os.MkdirAll(absComponentsDirPath, 0o750)
+	require.NoError(t, err, "error creating fake install components directory %q", absVersionedHomePath)
+
+	absLogsDirPath := filepath.Join(absVersionedHomePath, "logs")
+	err = os.MkdirAll(absLogsDirPath, 0o750)
+	require.NoError(t, err, "error creating fake install logs directory %q", absLogsDirPath)
+
+	absRunDirPath := filepath.Join(absVersionedHomePath, "run")
+	err = os.MkdirAll(absRunDirPath, 0o750)
+	require.NoError(t, err, "error creating fake install run directory %q", absRunDirPath)
+
+	// put some placeholder for files
+	agentExecutableName := upgrade.AgentName
+	if runtime.GOOS == "windows" {
+		agentExecutableName += ".exe"
+	}
+	err = os.WriteFile(paths.BinaryPath(absVersionedHomePath, agentExecutableName), []byte(fmt.Sprintf("Placeholder for agent %s", version)), 0o750)
+	require.NoErrorf(t, err, "error writing elastic agent binary placeholder %q", agentExecutableName)
+	fakeLogPath := filepath.Join(absLogsDirPath, "fakelog.ndjson")
+	err = os.WriteFile(fakeLogPath, []byte(fmt.Sprintf("Sample logs for agent %s", version)), 0o750)
+	require.NoErrorf(t, err, "error writing fake log placeholder %q", fakeLogPath)
+
+	// return the path relative to top exactly like the step_unpack does
+	return relVersionedHomePath
+}