Move component working directory management to coordinator

changelog/fragments/1761679059-move-component-workdir-coordinator.yaml

@@ -0,0 +1,32 @@
+# 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: Move component working directory management to coordinator
+
+# 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:
+
+# 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/owner/repo/1234
+
+# 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/application/coordinator/coordinator.go

@@ -946,10 +946,15 @@ func (c *Coordinator) watchRuntimeComponents(
 	state := make(map[string]runtime.ComponentState)
 
 	for {
+		var componentStates []runtime.ComponentComponentState
 		select {
 		case <-ctx.Done():
 			return
 		case componentState := <-runtimeComponentStates:
+			componentStates = append(componentStates, componentState)
+		case componentStates = <-otelComponentStates:
+		}
+		for _, componentState := range componentStates {
 			logComponentStateChange(c.logger, state, &componentState)
 			// Forward the final changes back to Coordinator, unless our context
 			// has ended.
@@ -958,21 +963,23 @@ func (c *Coordinator) watchRuntimeComponents(
 			case <-ctx.Done():
 				return
 			}
-		case componentStates := <-otelComponentStates:
-			for _, componentState := range componentStates {
-				logComponentStateChange(c.logger, state, &componentState)
-				// Forward the final changes back to Coordinator, unless our context
-				// has ended.
-				select {
-				case c.managerChans.runtimeManagerUpdate <- componentState:
-				case <-ctx.Done():
-					return
-				}
-			}
 		}
 	}
 }
 
+// ensureComponentWorkDirs ensures the component working directories exist for current components. This method is
+// idempotent.
+func (c *Coordinator) ensureComponentWorkDirs() error {
+	for _, comp := range c.componentModel {
+		c.logger.Debugf("Ensuring a working directory exists for component: %s", comp.ID)
+		err := comp.PrepareWorkDir(paths.Run())
+		if err != nil {
+			return fmt.Errorf("preparing a working directory for component %s failed: %w", comp.ID, err)
+		}
+	}
+	return nil
+}
+
 // logComponentStateChange emits a log message based on the new component state.
 func logComponentStateChange(
 	logger *logger.Logger,
@@ -1755,6 +1762,12 @@ func (c *Coordinator) refreshComponentModel(ctx context.Context) (err error) {
 		return fmt.Errorf("generating component model: %w", err)
 	}
 
+	// ensure all components have working directories
+	err = c.ensureComponentWorkDirs()
+	if err != nil {
+		return fmt.Errorf("ensuring component work dirs exists: %w", err)
+	}
+
 	signed, err := component.SignedFromPolicy(c.derivedConfig)
 	if err != nil {
 		if !errors.Is(err, component.ErrNotFound) {

internal/pkg/agent/application/coordinator/coordinator_state.go

@@ -6,10 +6,14 @@ package coordinator
 
 import (
 	"fmt"
+	"slices"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/status"
 	"go.opentelemetry.io/collector/component/componentstatus"
 
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/paths"
+	"github.com/elastic/elastic-agent/pkg/component"
+
 	"github.com/elastic/elastic-agent-client/v7/pkg/client"
 	"github.com/elastic/elastic-agent-libs/logp"
 
@@ -176,6 +180,17 @@ func (c *Coordinator) applyComponentState(state runtime.ComponentComponentState)
 				break
 			}
 		}
+		// If the component was stopped and isn't listed among components the coordinator knows about, it's safe to
+		// remove its working directory. Otherwise, we may just be moving it between runtimes.
+		if !slices.ContainsFunc(c.componentModel, func(c component.Component) bool {
+			return state.Component.ID == c.ID
+		}) {
+			c.logger.Debugf("removing working directory for component '%s'", state.Component.ID)
+			err := state.Component.RemoveWorkDir(paths.Run())
+			if err != nil {
+				c.logger.Warnf("failed to remove workdir for component %s: %v", state.Component.ID, err)
+			}
+		}
 	}
 
 	c.stateNeedsRefresh = true

internal/pkg/agent/application/coordinator/coordinator_unit_test.go

@@ -1152,6 +1152,174 @@ service:
 
 }
 
+func TestCoordinatorManagesComponentWorkDirs(t *testing.T) {
+	// Send a test policy to the Coordinator as a Config Manager update,
+	// verify it creates a working directory for the component, keeps that working directory as the component
+	// moves to a different runtime, then deletes it after the component is stopped.
+	top := paths.Top()
+	paths.SetTop(t.TempDir())
+	t.Cleanup(func() {
+		paths.SetTop(top)
+	})
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	logger := logp.NewLogger("testing")
+
+	configChan := make(chan ConfigChange, 1)
+	updateChan := make(chan runtime.ComponentComponentState, 1)
+
+	// Create a mocked runtime manager that will report the update call
+	runtimeManager := &fakeRuntimeManager{}
+	otelManager := &fakeOTelManager{}
+
+	// we need the filestream spec to be able to convert to Otel config
+	componentSpec := component.InputRuntimeSpec{
+		InputType:  "filestream",
+		BinaryName: "agentbeat",
+		Spec: component.InputSpec{
+			Name: "filestream",
+			Command: &component.CommandSpec{
+				Args: []string{"filebeat"},
+			},
+			Platforms: []string{
+				"linux/amd64",
+				"linux/arm64",
+				"darwin/amd64",
+				"darwin/arm64",
+				"windows/amd64",
+				"container/amd64",
+				"container/arm64",
+			},
+		},
+	}
+
+	platform, err := component.LoadPlatformDetail()
+	require.NoError(t, err)
+	specs, err := component.NewRuntimeSpecs(platform, []component.InputRuntimeSpec{componentSpec})
+	require.NoError(t, err)
+
+	monitoringMgr := newTestMonitoringMgr()
+	coord := &Coordinator{
+		logger:           logger,
+		agentInfo:        &info.AgentInfo{},
+		stateBroadcaster: broadcaster.New(State{}, 0, 0),
+		managerChans: managerChans{
+			configManagerUpdate:  configChan,
+			runtimeManagerUpdate: updateChan,
+		},
+		monitorMgr:         monitoringMgr,
+		runtimeMgr:         runtimeManager,
+		otelMgr:            otelManager,
+		specs:              specs,
+		vars:               emptyVars(t),
+		componentPIDTicker: time.NewTicker(time.Second * 30),
+		secretMarkerFunc:   testSecretMarkerFunc,
+	}
+
+	var workDirPath string
+	var workDirCreated time.Time
+
+	t.Run("run in process manager", func(t *testing.T) {
+		// Create a policy with one input and one output (no otel configuration)
+		cfg := config.MustNewConfigFrom(`
+outputs:
+  default:
+    type: elasticsearch
+    hosts:
+      - localhost:9200
+inputs:
+  - id: test-input
+    type: filestream
+    use_output: default
+    _runtime_experimental: process
+`)
+
+		// Send the policy change and make sure it was acknowledged.
+		cfgChange := &configChange{cfg: cfg}
+		configChan <- cfgChange
+		coord.runLoopIteration(ctx)
+		assert.True(t, cfgChange.acked, "Coordinator should ACK a successful policy change")
+		assert.NoError(t, cfgChange.err, "config processing shouldn't report an error")
+		require.Len(t, coord.componentModel, 1, "there should be one component")
+		workDirPath = coord.componentModel[0].WorkDirPath(paths.Run())
+		stat, err := os.Stat(workDirPath)
+		require.NoError(t, err, "component working directory should exist")
+		assert.True(t, stat.IsDir(), "component working directory should exist")
+		workDirCreated = stat.ModTime()
+	})
+
+	t.Run("run in otel manager", func(t *testing.T) {
+		// Create a policy with one input and one output (no otel configuration)
+		cfg := config.MustNewConfigFrom(`
+outputs:
+  default:
+    type: elasticsearch
+    hosts:
+      - localhost:9200
+inputs:
+  - id: test-input
+    type: filestream
+    use_output: default
+    _runtime_experimental: otel
+`)
+
+		// Send the policy change and make sure it was acknowledged.
+		cfgChange := &configChange{cfg: cfg}
+		configChan <- cfgChange
+		coord.runLoopIteration(ctx)
+		assert.True(t, cfgChange.acked, "Coordinator should ACK a successful policy change")
+		assert.NoError(t, cfgChange.err, "config processing shouldn't report an error")
+		require.Len(t, coord.componentModel, 1, "there should be one component")
+		compState := runtime.ComponentComponentState{
+			Component: component.Component{
+				ID: "filestream-default",
+			},
+			State: runtime.ComponentState{
+				State: client.UnitStateStopped,
+			},
+		}
+		updateChan <- compState
+		coord.runLoopIteration(ctx)
+		stat, err := os.Stat(workDirPath)
+		require.NoError(t, err, "component working directory should exist")
+		assert.True(t, stat.IsDir(), "component working directory should exist")
+		assert.Equal(t, workDirCreated, stat.ModTime(), "component working directory shouldn't have been modified")
+	})
+	t.Run("remove component", func(t *testing.T) {
+		// Create a policy with one input and one output (no otel configuration)
+		cfg := config.MustNewConfigFrom(`
+outputs:
+  default:
+    type: elasticsearch
+    hosts:
+      - localhost:9200
+inputs: []
+`)
+
+		// Send the policy change and make sure it was acknowledged.
+		cfgChange := &configChange{cfg: cfg}
+		configChan <- cfgChange
+		coord.runLoopIteration(ctx)
+		assert.True(t, cfgChange.acked, "Coordinator should ACK a successful policy change")
+		assert.NoError(t, cfgChange.err, "config processing shouldn't report an error")
+		require.Len(t, coord.componentModel, 0, "there should be one component")
+
+		compState := runtime.ComponentComponentState{
+			Component: component.Component{
+				ID: "filestream-default",
+			},
+			State: runtime.ComponentState{
+				State: client.UnitStateStopped,
+			},
+		}
+		updateChan <- compState
+		coord.runLoopIteration(ctx)
+		assert.NoDirExists(t, workDirPath, "component working directory shouldn't exist anymore")
+	})
+
+}
+
 func TestCoordinatorReportsRuntimeManagerUpdateFailure(t *testing.T) {
 	// Set a one-second timeout -- nothing here should block, but if it
 	// does let's report a failure instead of timing out the test runner.

pkg/component/component.go

@@ -9,6 +9,9 @@ import (
 	"errors"
 	"fmt"
 	"maps"
+	"os"
+	"path/filepath"
+	"runtime"
 	"slices"
 	"sort"
 	"strings"
@@ -39,6 +42,7 @@ const (
 	defaultUnitLogLevel                  = client.UnitLogLevelInfo
 	headersKey                           = "headers"
 	elasticsearchType                    = "elasticsearch"
+	workDirPathMod                       = 0770
 	ProcessRuntimeManager                = RuntimeManager("process")
 	OtelRuntimeManager                   = RuntimeManager("otel")
 	DefaultRuntimeManager RuntimeManager = ProcessRuntimeManager
@@ -238,6 +242,44 @@ func (c *Component) BinaryName() string {
 	return ""
 }
 
+// WorkDirName returns the name of the component's working directory.
+func (c *Component) WorkDirName() string {
+	return c.ID
+}
+
+// WorkDirPath returns the full path of the component's working directory, placing it under the provided parent path.
+func (c *Component) WorkDirPath(parentDirPath string) string {
+	return filepath.Join(parentDirPath, c.WorkDirName())
+}
+
+// PrepareWorkDir prepares the component working directory under the provided parent path. This involves creating
+// it under the right ownership and ACLs. This method is idempotent.
+func (c *Component) PrepareWorkDir(parentDirPath string) error {
+	uid, gid := os.Geteuid(), os.Getegid()
+	path := c.WorkDirPath(parentDirPath)
+	err := os.MkdirAll(path, workDirPathMod)
+	if err != nil {
+		return fmt.Errorf("failed to create path %q: %w", path, err)
+	}
+	if runtime.GOOS == Windows {
+		return nil
+	}
+	err = os.Chown(path, uid, gid)
+	if err != nil {
+		return fmt.Errorf("failed to chown %q: %w", path, err)
+	}
+	err = os.Chmod(path, workDirPathMod)
+	if err != nil {
+		return fmt.Errorf("failed to chmod %q: %w", path, err)
+	}
+	return nil
+}
+
+// RemoveWorkDir removes the component working directory under the provided parent path. This method is idempotent.
+func (c *Component) RemoveWorkDir(parentDirPath string) error {
+	return os.RemoveAll(c.WorkDirPath(parentDirPath))
+}
+
 // Model is the components model with signed policy data
 // This replaces former top level []Components with the top Model that captures signed policy data.
 // The signed data is a part of the policy since 8.8.0 release and contains the signed policy fragments and the signature that can be validated.