Update will cleanup unneeded artifacts. (#752)

* Update will cleanup unneeded artifacts.

The update process will cleanup unneeded artifacts. When an update
starts all artifacts that do not have the current version number in it's
name will be removed. If artifact retrieval fails, downloaded artifacts
are removed. On a successful upgrade, all contents of the downloads dir
will be removed.

* Clean up linter warnings

* Wrap errors

* cleanup tests

* Fix passed version

* Use os.RemoveAll

CHANGELOG.next.asciidoc

@@ -111,6 +111,7 @@
 - Allow the - char to appear as part of variable names in eql expressions. {issue}709[709] {pull}710[710]
 - Allow the / char in variable names in eql and transpiler. {issue}715[715] {pull}718[718]
 - Fix data duplication for standalone agent on Kubernetes using the default manifest {issue-beats}31512[31512] {pull}742[742]
+- Agent updates will clean up unneeded artifacts. {issue}693[693] {issue}694[694] {pull}752[752]
 
 ==== New features
 

internal/pkg/agent/application/upgrade/cleanup.go

@@ -0,0 +1,36 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package upgrade
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/hashicorp/go-multierror"
+
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/paths"
+)
+
+// preUpgradeCleanup will remove files that do not have the passed version number from the downloads directory.
+func preUpgradeCleanup(version string) error {
+	files, err := os.ReadDir(paths.Downloads())
+	if err != nil {
+		return fmt.Errorf("unable to read directory %q: %w", paths.Downloads(), err)
+	}
+	var rErr error
+	for _, file := range files {
+		if file.IsDir() {
+			continue
+		}
+		if !strings.Contains(file.Name(), version) {
+			if err := os.Remove(filepath.Join(paths.Downloads(), file.Name())); err != nil {
+				rErr = multierror.Append(rErr, fmt.Errorf("unable to remove file %q: %w", filepath.Join(paths.Downloads(), file.Name()), err))
+			}
+		}
+	}
+	return rErr
+}

internal/pkg/agent/application/upgrade/cleanup_test.go

@@ -0,0 +1,44 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package upgrade
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/paths"
+
+	"github.com/stretchr/testify/require"
+)
+
+func setupDir(t *testing.T) {
+	t.Helper()
+	dir := t.TempDir()
+	paths.SetDownloads(dir)
+
+	err := os.WriteFile(filepath.Join(dir, "test-8.3.0-file"), []byte("hello, world!"), 0600)
+	require.NoError(t, err)
+	err = os.WriteFile(filepath.Join(dir, "test-8.4.0-file"), []byte("hello, world!"), 0600)
+	require.NoError(t, err)
+	err = os.WriteFile(filepath.Join(dir, "test-8.5.0-file"), []byte("hello, world!"), 0600)
+	require.NoError(t, err)
+	err = os.WriteFile(filepath.Join(dir, "test-hash-file"), []byte("hello, world!"), 0600)
+	require.NoError(t, err)
+}
+
+func TestPreUpgradeCleanup(t *testing.T) {
+	setupDir(t)
+	err := preUpgradeCleanup("8.4.0")
+	require.NoError(t, err)
+
+	files, err := os.ReadDir(paths.Downloads())
+	require.NoError(t, err)
+	require.Len(t, files, 1)
+	require.Equal(t, "test-8.4.0-file", files[0].Name())
+	p, err := os.ReadFile(filepath.Join(paths.Downloads(), files[0].Name()))
+	require.NoError(t, err)
+	require.Equal(t, []byte("hello, world!"), p)
+}

internal/pkg/agent/application/upgrade/upgrade.go

@@ -126,6 +126,11 @@ func (u *Upgrader) Upgrade(ctx context.Context, a Action, reexecNow bool) (_ ree
 				"running under control of the systems supervisor")
 	}
 
+	err = preUpgradeCleanup(u.agentInfo.Version())
+	if err != nil {
+		u.log.Errorf("Unable to clean downloads dir %q before update: %v", paths.Downloads(), err)
+	}
+
 	if u.caps != nil {
 		if _, err := u.caps.Apply(a); errors.Is(err, capabilities.ErrBlocked) {
 			return nil, nil
@@ -137,6 +142,11 @@ func (u *Upgrader) Upgrade(ctx context.Context, a Action, reexecNow bool) (_ ree
 	sourceURI := u.sourceURI(a.SourceURI())
 	archivePath, err := u.downloadArtifact(ctx, a.Version(), sourceURI)
 	if err != nil {
+		// Run the same preUpgradeCleanup task to get rid of any newly downloaded files
+		// This may have an issue if users are upgrading to the same version number.
+		if dErr := preUpgradeCleanup(u.agentInfo.Version()); dErr != nil {
+			u.log.Errorf("Unable to remove file after verification failure: %v", dErr)
+		}
 		return nil, err
 	}
 
@@ -180,10 +190,20 @@ func (u *Upgrader) Upgrade(ctx context.Context, a Action, reexecNow bool) (_ ree
 
 	cb := shutdownCallback(u.log, paths.Home(), release.Version(), a.Version(), release.TrimCommit(newHash))
 	if reexecNow {
+		err = os.RemoveAll(paths.Downloads())
+		if err != nil {
+			u.log.Errorf("Unable to clean downloads dir %q after update: %v", paths.Downloads(), err)
+		}
 		u.reexec.ReExec(cb)
 		return nil, nil
 	}
 
+	// Clean everything from the downloads dir
+	err = os.RemoveAll(paths.Downloads())
+	if err != nil {
+		u.log.Errorf("Unable to clean downloads dir %q after update: %v", paths.Downloads(), err)
+	}
+
 	return cb, nil
 }