Ensure socket path is < 104 characters when STATE_PATH is set.

changelog/fragments/1718226176-Ensure.yaml

@@ -0,0 +1,35 @@
+# Kind can be one of:
+# - breaking-change: a change to previously-documented behavior
+# - deprecation: functionality that is being removed in a later release
+# - bug-fix: fixes a problem in a previous version
+# - enhancement: extends functionality but does not break or fix existing behavior
+# - feature: new functionality
+# - known-issue: problems that we are aware of in a given version
+# - security: impacts on the security of a product or a user’s deployment.
+# - upgrade: important information for someone upgrading from a prior version
+# - other: does not fit into any of the other categories
+kind: bug-fix
+
+# Change summary; a 80ish characters long description of the change.
+summary: Ensure socket can be created even when STATE_PATH is too long for container command
+
+# Long description; in case the summary is not enough to describe the change
+# this field accommodate a description without length limits.
+# NOTE: This field will be rendered only for breaking-change and known-issue kinds at the moment.
+description: |
+  When running the Elastic-Agent container command and `STATE_PATH` is
+  set to a value that is too long the Unix socket cannot be created,
+  so the Elastic-Agent will use the default state path instead.
+
+# Affected component; usually one of "elastic-agent", "fleet-server", "filebeat", "metricbeat", "auditbeat", "all", etc.
+component: elastic-agent
+
+# PR URL; optional; the PR number that added the changeset.
+# If not present is automatically filled by the tooling finding the PR where this changelog fragment has been added.
+# NOTE: the tooling supports backports, so it's able to fill the original PR number instead of the backport PR number.
+# Please provide it if you are adding a fragment for a different PR.
+pr: https://github.com/elastic/elastic-agent/pull/4909
+
+# Issue URL; optional; the GitHub issue related to this changeset (either closes or is part of).
+# If not present is automatically filled by the tooling with the issue linked to the PR number.
+#issue: https://github.com/owner/repo/1234

internal/pkg/agent/cmd/container.go

@@ -34,6 +34,7 @@ import (
 	"github.com/elastic/elastic-agent/pkg/component"
 	"github.com/elastic/elastic-agent/pkg/core/logger"
 	"github.com/elastic/elastic-agent/pkg/core/process"
+	"github.com/elastic/elastic-agent/pkg/utils"
 	"github.com/elastic/elastic-agent/version"
 )
 
@@ -774,13 +775,20 @@ func setPaths(statePath, configPath, logsPath, socketPath string, writePaths boo
 	if statePath == "" {
 		statePath = defaultStateDirectory
 	}
+
 	topPath := filepath.Join(statePath, "data")
 	configPath = envWithDefault(configPath, "CONFIG_PATH")
 	if configPath == "" {
 		configPath = statePath
 	}
+	if _, err := os.Stat(configPath); errors.Is(err, fs.ErrNotExist) {
+		if err := os.MkdirAll(configPath, 0755); err != nil {
+			return fmt.Errorf("cannot create folders for config path '%s': %w", configPath, err)
+		}
+	}
+
 	if socketPath == "" {
-		socketPath = fmt.Sprintf("unix://%s", filepath.Join(topPath, paths.ControlSocketName))
+		socketPath = utils.SocketURLWithFallback(statePath, topPath)
 	}
 	// ensure that the directory and sub-directory data exists
 	if err := os.MkdirAll(topPath, 0755); err != nil {

testing/integration/container_cmd_test.go

@@ -2,14 +2,16 @@
 // or more contributor license agreements. Licensed under the Elastic License;
 // you may not use this file except in compliance with the Elastic License.
 
-//go:build integration
+//go:build integration && linux
 
 package integration
 
 import (
 	"context"
 	"fmt"
 	"os"
+	"os/exec"
+	"path/filepath"
 	"strings"
 	"testing"
 	"time"
@@ -18,29 +20,12 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/elastic/elastic-agent-libs/kibana"
+	atesting "github.com/elastic/elastic-agent/pkg/testing"
 	"github.com/elastic/elastic-agent/pkg/testing/define"
 	"github.com/elastic/elastic-agent/pkg/testing/tools/fleettools"
 )
 
-func TestContainerCMD(t *testing.T) {
-	info := define.Require(t, define.Requirements{
-		Stack: &define.Stack{},
-		Local: false,
-		Sudo:  true,
-		OS: []define.OS{
-			{Type: define.Linux},
-		},
-		// This test runs the command we use when executing inside a container
-		// which leaves files under /usr/share/elastic-agent. Run it isolated
-		// to avoid interfering with other tests and better simulate a container
-		// environment we run it in isolation
-		Group: "container",
-	})
-	ctx := context.Background()
-
-	agentFixture, err := define.NewFixtureFromLocalBuild(t, define.Version())
-	require.NoError(t, err)
-
+func createPolicy(t *testing.T, ctx context.Context, agentFixture *atesting.Fixture, info *define.Info) string {
 	createPolicyReq := kibana.AgentPolicy{
 		Name:        fmt.Sprintf("test-policy-enroll-%s", uuid.New().String()),
 		Namespace:   info.Namespace,
@@ -74,13 +59,10 @@ func TestContainerCMD(t *testing.T) {
 		t.Fatalf("unable to create enrolment API key: %s", err)
 	}
 
-	fleetURL, err := fleettools.DefaultURL(ctx, info.KibanaClient)
-	if err != nil {
-		t.Fatalf("could not get Fleet URL: %s", err)
-	}
+	return enrollmentToken.APIKey
+}
 
-	ctx, cancel := context.WithTimeout(ctx, 1*time.Minute)
-	defer cancel()
+func prepareContainerCMD(t *testing.T, ctx context.Context, agentFixture *atesting.Fixture, info *define.Info, env []string) *exec.Cmd {
 	cmd, err := agentFixture.PrepareAgentCommand(ctx, []string{"container"})
 	if err != nil {
 		t.Fatalf("could not prepare agent command: %s", err)
@@ -112,22 +94,52 @@ func TestContainerCMD(t *testing.T) {
 	agentOutput := strings.Builder{}
 	cmd.Stderr = &agentOutput
 	cmd.Stdout = &agentOutput
-	cmd.Env = append(os.Environ(),
+	cmd.Env = append(os.Environ(), env...)
+	return cmd
+}
+
+func TestContainerCMD(t *testing.T) {
+	info := define.Require(t, define.Requirements{
+		Stack: &define.Stack{},
+		Local: false,
+		Sudo:  true,
+		OS: []define.OS{
+			{Type: define.Linux},
+		},
+		Group: "container",
+	})
+
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
+	defer cancel()
+
+	agentFixture, err := define.NewFixtureFromLocalBuild(t, define.Version())
+	require.NoError(t, err)
+
+	fleetURL, err := fleettools.DefaultURL(ctx, info.KibanaClient)
+	if err != nil {
+		t.Fatalf("could not get Fleet URL: %s", err)
+	}
+
+	enrollmentToken := createPolicy(t, ctx, agentFixture, info)
+	env := []string{
 		"FLEET_ENROLL=1",
-		"FLEET_URL="+fleetURL,
-		"FLEET_ENROLLMENT_TOKEN="+enrollmentToken.APIKey,
+		"FLEET_URL=" + fleetURL,
+		"FLEET_ENROLLMENT_TOKEN=" + enrollmentToken,
 		// As the agent isn't built for a container, it's upgradable, triggering
 		// the start of the upgrade watcher. If `STATE_PATH` isn't set, the
 		// upgrade watcher will commence from a different path within the
 		// container, distinct from the current execution path.
-		"STATE_PATH="+agentFixture.WorkDir(),
-	)
+		"STATE_PATH=" + agentFixture.WorkDir(),
+	}
 
+	cmd := prepareContainerCMD(t, ctx, agentFixture, info, env)
 	t.Logf(">> running binary with: %v", cmd.Args)
 	if err := cmd.Start(); err != nil {
 		t.Fatalf("error running container cmd: %s", err)
 	}
 
+	agentOutput := cmd.Stderr.(*strings.Builder)
+
 	require.Eventuallyf(t, func() bool {
 		// This will return errors until it connects to the agent,
 		// they're mostly noise because until the agent starts running
@@ -140,6 +152,114 @@ func TestContainerCMD(t *testing.T) {
 	},
 		5*time.Minute, time.Second,
 		"Elastic-Agent did not report healthy. Agent status error: \"%v\", Agent logs\n%s",
-		err, &agentOutput,
+		err, agentOutput,
 	)
 }
+
+func TestContainerCMDWithAVeryLongStatePath(t *testing.T) {
+	info := define.Require(t, define.Requirements{
+		Stack: &define.Stack{},
+		Local: false,
+		Sudo:  true,
+		OS: []define.OS{
+			{Type: define.Linux},
+		},
+		Group: "container",
+	})
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
+	defer cancel()
+
+	fleetURL, err := fleettools.DefaultURL(ctx, info.KibanaClient)
+	if err != nil {
+		t.Fatalf("could not get Fleet URL: %s", err)
+	}
+
+	testCases := map[string]struct {
+		statePath          string
+		expectedStatePath  string
+		expectedSocketPath string
+		expectError        bool
+	}{
+		"small path": { // Use the set path
+			statePath:          filepath.Join(os.TempDir(), "foo", "bar"),
+			expectedStatePath:  filepath.Join(os.TempDir(), "foo", "bar"),
+			expectedSocketPath: "/tmp/foo/bar/data/smp7BzlzcwgrLK4PUxpu7G1O5UwV4adr.sock",
+		},
+		"no path set": { // Use the default path
+			statePath:          "",
+			expectedStatePath:  "/usr/share/elastic-agent/state",
+			expectedSocketPath: "/usr/share/elastic-agent/state/data/Td8I7R-Zby36_zF_IOd9QVNlFblNEro3.sock",
+		},
+		"107 characters path": { // Longest path that still works for creating a unix socket, but will use /tmp/elastic-agent
+			statePath:          "/tmp/tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt",
+			expectedStatePath:  "/tmp/tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt",
+			expectedSocketPath: "/tmp/elastic-agent/oKUUJbxrLlGSh3z6wZWYleLeMuUN4P0_.sock",
+		},
+		"long path": { // Path too long to create a unix socket, it will use /tmp/elastic-agent
+			statePath:          "/tmp/ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+			expectedStatePath:  "/tmp/ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+			expectedSocketPath: "/tmp/elastic-agent/Xegnlbb8QDcqNLPzyf2l8PhVHjWvlQgZ.sock",
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			agentFixture, err := define.NewFixtureFromLocalBuild(t, define.Version())
+			require.NoError(t, err)
+
+			enrollmentToken := createPolicy(t, ctx, agentFixture, info)
+			env := []string{
+				"FLEET_ENROLL=1",
+				"FLEET_URL=" + fleetURL,
+				"FLEET_ENROLLMENT_TOKEN=" + enrollmentToken,
+				"STATE_PATH=" + tc.statePath,
+			}
+
+			cmd := prepareContainerCMD(t, ctx, agentFixture, info, env)
+			t.Logf(">> running binary with: %v", cmd.Args)
+			if err := cmd.Start(); err != nil {
+				t.Fatalf("error running container cmd: %s", err)
+			}
+			agentOutput := cmd.Stderr.(*strings.Builder)
+
+			require.Eventuallyf(t, func() bool {
+				// This will return errors until it connects to the agent,
+				// they're mostly noise because until the agent starts running
+				// we will get connection errors. If the test fails
+				// the agent logs will be present in the error message
+				// which should help to explain why the agent was not
+				// healthy.
+				err = agentFixture.IsHealthy(ctx)
+				return err == nil
+			},
+				1*time.Minute, time.Second,
+				"Elastic-Agent did not report healthy. Agent status error: \"%v\", Agent logs\n%s",
+				err, agentOutput,
+			)
+
+			t.Cleanup(func() {
+				_ = os.RemoveAll(tc.expectedStatePath)
+			})
+
+			// Now that the Elastic-Agent is healthy, check that the control socket path
+			// is the expected one
+			if _, err := os.Stat(tc.expectedStatePath); err != nil {
+				t.Errorf("cannot stat expected state path ('%s'): %s", tc.expectedStatePath, err)
+			}
+			if _, err := os.Stat(tc.expectedSocketPath); err != nil {
+				t.Errorf("cannot stat expected socket path ('%s'): %s", tc.expectedSocketPath, err)
+			}
+
+			if t.Failed() {
+				containerPaths, err := os.ReadFile(filepath.Join(agentFixture.WorkDir(), "container-paths.yml"))
+				if err != nil {
+					t.Fatalf("could not read container-paths.yml: %s", err)
+				}
+
+				t.Log("contents of 'container-paths-yml'")
+				t.Log(string(containerPaths))
+			}
+		})
+	}
+}