From f6a17fe3d9990c1d383158355424d68e39bce9c0 Mon Sep 17 00:00:00 2001
From: James Pickett <James-Pickett@users.noreply.github.com>
Date: Thu, 19 Dec 2024 10:01:43 -0800
Subject: [PATCH] drop reqs when detection locked (#2008)

---
 ee/desktop/runner/runner.go       |  7 +++----
 ee/desktop/runner/runner_test.go  | 31 +++++++++++++++++++++++++++++++
 ee/localserver/request-id.go      |  1 -
 ee/localserver/request-id_test.go |  1 -
 ee/localserver/server.go          | 10 ++++++----
 5 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/ee/desktop/runner/runner.go b/ee/desktop/runner/runner.go
index d5bf62d7a..5805e7d87 100644
--- a/ee/desktop/runner/runner.go
+++ b/ee/desktop/runner/runner.go
@@ -290,21 +290,20 @@ func (r *DesktopUsersProcessesRunner) DetectPresence(reason string, interval tim
 	}
 
 	var lastErr error
-	var lastDurationSinceLastDetection time.Duration
 
 	for _, proc := range r.uidProcs {
 		client := client.New(r.userServerAuthToken, proc.socketPath)
-		lastDurationSinceLastDetection, err := client.DetectPresence(reason, interval)
 
+		durationSinceLastDetection, err := client.DetectPresence(reason, interval)
 		if err != nil {
 			lastErr = err
 			continue
 		}
 
-		return lastDurationSinceLastDetection, nil
+		return durationSinceLastDetection, nil
 	}
 
-	return lastDurationSinceLastDetection, fmt.Errorf("no desktop processes detected presence, last error: %w", lastErr)
+	return presencedetection.DetectionFailedDurationValue, fmt.Errorf("no desktop processes detected presence, last error: %w", lastErr)
 }
 
 // killDesktopProcesses kills any existing desktop processes
diff --git a/ee/desktop/runner/runner_test.go b/ee/desktop/runner/runner_test.go
index 6b72d311d..217a01f2c 100644
--- a/ee/desktop/runner/runner_test.go
+++ b/ee/desktop/runner/runner_test.go
@@ -18,6 +18,7 @@ import (
 	"github.com/kolide/launcher/ee/agent/flags/keys"
 	"github.com/kolide/launcher/ee/agent/types/mocks"
 	"github.com/kolide/launcher/ee/desktop/user/notify"
+	"github.com/kolide/launcher/ee/presencedetection"
 	"github.com/kolide/launcher/pkg/backoff"
 	"github.com/kolide/launcher/pkg/log/multislogger"
 	"github.com/kolide/launcher/pkg/threadsafebuffer"
@@ -493,3 +494,33 @@ func countFilesWithPrefix(folderPath, prefix string) (int, error) {
 
 	return count, nil
 }
+
+func TestDesktopUsersProcessesRunner_DetectPresence(t *testing.T) {
+	t.Parallel()
+
+	t.Run("no user procs", func(t *testing.T) {
+		t.Parallel()
+
+		runner := DesktopUsersProcessesRunner{}
+		d, err := runner.DetectPresence("whatevs", time.Second)
+		require.Error(t, err)
+		require.Equal(t, presencedetection.DetectionFailedDurationValue, d)
+	})
+
+	t.Run("cant connect to user server", func(t *testing.T) {
+		t.Parallel()
+
+		u, err := user.Current()
+		require.NoError(t, err)
+
+		runner := DesktopUsersProcessesRunner{
+			uidProcs: map[string]processRecord{
+				u.Uid: {},
+			},
+		}
+
+		d, err := runner.DetectPresence("whatevs", time.Second)
+		require.Error(t, err)
+		require.Equal(t, presencedetection.DetectionFailedDurationValue, d)
+	})
+}
diff --git a/ee/localserver/request-id.go b/ee/localserver/request-id.go
index aad795413..0ecf3eafa 100644
--- a/ee/localserver/request-id.go
+++ b/ee/localserver/request-id.go
@@ -84,7 +84,6 @@ func (ls *localServer) requestIdHandlerFunc(w http.ResponseWriter, r *http.Reque
 		Origin:    r.Header.Get("Origin"),
 		Status: status{
 			EnrollmentStatus: string(enrollmentStatus),
-			InstanceStatuses: ls.knapsack.InstanceStatuses(),
 		},
 	}
 	response.identifiers = ls.identifiers
diff --git a/ee/localserver/request-id_test.go b/ee/localserver/request-id_test.go
index d6a0af54a..8873bb34c 100644
--- a/ee/localserver/request-id_test.go
+++ b/ee/localserver/request-id_test.go
@@ -27,7 +27,6 @@ func Test_localServer_requestIdHandler(t *testing.T) {
 	mockKnapsack.On("ConfigStore").Return(storageci.NewStore(t, multislogger.NewNopLogger(), storage.ConfigStore.String()))
 	mockKnapsack.On("KolideServerURL").Return("localhost")
 	mockKnapsack.On("CurrentEnrollmentStatus").Return(types.Enrolled, nil)
-	mockKnapsack.On("InstanceStatuses").Return(map[string]types.InstanceStatus{"default": types.InstanceStatusHealthy})
 
 	var logBytes bytes.Buffer
 	slogger := slog.New(slog.NewJSONHandler(&logBytes, &slog.HandlerOptions{
diff --git a/ee/localserver/server.go b/ee/localserver/server.go
index 053c09de4..9646d4aee 100644
--- a/ee/localserver/server.go
+++ b/ee/localserver/server.go
@@ -419,10 +419,6 @@ func (ls *localServer) rateLimitHandler(next http.Handler) http.Handler {
 
 func (ls *localServer) presenceDetectionHandler(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		// ensure we only prompt for 1 presence detection at a time
-		ls.presenceDetectionMutex.Lock()
-		defer ls.presenceDetectionMutex.Unlock()
-
 		// can test this by adding an unauthed endpoint to the mux and running, for example:
 		// curl -i -H "X-Kolide-Presence-Detection-Interval: 10s" -H "X-Kolide-Presence-Detection-Reason: my reason" localhost:12519/id
 		detectionIntervalStr := r.Header.Get(kolidePresenceDetectionIntervalHeaderKey)
@@ -461,6 +457,12 @@ func (ls *localServer) presenceDetectionHandler(next http.Handler) http.Handler
 			)
 		}
 
+		if !ls.presenceDetectionMutex.TryLock() {
+			http.Error(w, "presence detection already in progress", http.StatusTooManyRequests)
+			return
+		}
+		defer ls.presenceDetectionMutex.Unlock()
+
 		durationSinceLastDetection, err := ls.presenceDetector.DetectPresence(reason, detectionIntervalDuration)
 
 		if err != nil {