test: make tests independent of containerID ordering

statsd/buffer_test.go

@@ -7,6 +7,7 @@ import (
 )
 
 func TestBufferGauge(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 1)
 	err := buffer.writeGauge("namespace.", []string{"tag:tag"}, "metric", 1, []string{}, 1, noTimestamp, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -44,6 +45,7 @@ func TestBufferGauge(t *testing.T) {
 }
 
 func TestBufferCount(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 1)
 	err := buffer.writeCount("namespace.", []string{"tag:tag"}, "metric", 1, []string{}, 1, noTimestamp, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -81,6 +83,7 @@ func TestBufferCount(t *testing.T) {
 }
 
 func TestBufferHistogram(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 1)
 	err := buffer.writeHistogram("namespace.", []string{"tag:tag"}, "metric", 1, []string{}, 1, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -112,6 +115,7 @@ func TestBufferHistogram(t *testing.T) {
 }
 
 func TestBufferDistribution(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 1)
 	err := buffer.writeDistribution("namespace.", []string{"tag:tag"}, "metric", 1, []string{}, 1, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -142,6 +146,7 @@ func TestBufferDistribution(t *testing.T) {
 	assert.Equal(t, "namespace.metric:1|d|#tag:tag|c:container-id|e:external-env|card:low\n", string(buffer.bytes()))
 }
 func TestBufferSet(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 1)
 	err := buffer.writeSet("namespace.", []string{"tag:tag"}, "metric", "value", []string{}, 1, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -173,6 +178,7 @@ func TestBufferSet(t *testing.T) {
 }
 
 func TestBufferTiming(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 1)
 	err := buffer.writeTiming("namespace.", []string{"tag:tag"}, "metric", 1, []string{}, 1, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -204,6 +210,7 @@ func TestBufferTiming(t *testing.T) {
 }
 
 func TestBufferEvent(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 1)
 	err := buffer.writeEvent(&Event{Title: "title", Text: "text"}, []string{"tag:tag"}, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -235,6 +242,7 @@ func TestBufferEvent(t *testing.T) {
 }
 
 func TestBufferServiceCheck(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 1)
 	err := buffer.writeServiceCheck(&ServiceCheck{Name: "name", Status: Ok}, []string{"tag:tag"}, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -266,6 +274,7 @@ func TestBufferServiceCheck(t *testing.T) {
 }
 
 func TestBufferFullSize(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(30, 10)
 	err := buffer.writeGauge("namespace.", []string{"tag:tag"}, "metric", 1, []string{}, 1, noTimestamp, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -275,6 +284,7 @@ func TestBufferFullSize(t *testing.T) {
 }
 
 func TestBufferSeparator(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 10)
 	err := buffer.writeGauge("namespace.", []string{"tag:tag"}, "metric", 1, []string{}, 1, noTimestamp, true, CardinalityNotSet)
 	assert.Nil(t, err)
@@ -284,6 +294,7 @@ func TestBufferSeparator(t *testing.T) {
 }
 
 func TestBufferAggregated(t *testing.T) {
+	withoutOriginGlobals(t)
 	buffer := newStatsdBuffer(1024, 1)
 	pos, err := buffer.writeAggregated([]byte("h"), "namespace.", []string{"tag:tag"}, "metric", []float64{1}, "", 12, -1, 1, true, CardinalityNotSet)
 	assert.Nil(t, err)

statsd/container.go

@@ -2,18 +2,31 @@ package statsd
 
 import (
 	"sync"
+	"sync/atomic"
 )
 
 var (
-	// containerID holds the container ID.
-	containerID = ""
-
-	initOnce sync.Once
+	containerID atomic.Value
+	initOnce    sync.Once
 )
 
-// getContainerID returns the container ID configured at the client creation
+func init() {
+	// Pre-seed with an empty string so Load never returns nil and the
+	// type-assertion in the read path is unconditional.
+	containerID.Store("")
+}
+
+// getContainerID returns the container ID configured at the client creation.
 // It can either be auto-discovered with origin detection or provided by the user.
 // User-defined container ID is prioritized.
 func getContainerID() string {
-	return containerID
+	return containerID.Load().(string)
+}
+
+func storeContainerID(id string) {
+	containerID.Store(id)
+}
+
+func setContainerIDForTest(id string) {
+	containerID.Store(id)
 }

statsd/container_linux.go

@@ -193,27 +193,27 @@ func internalInitContainerID(userProvidedID string, cgroupFallback, isHostCgroup
 // readCIDOrInode reads the container ID from the user provided ID, cgroups or mountinfo.
 func readCIDOrInode(userProvidedID, cgroupPath, selfMountInfoPath, defaultCgroupMountPath string, cgroupFallback, isHostCgroupNs bool) {
 	if userProvidedID != "" {
-		containerID = userProvidedID
+		storeContainerID(userProvidedID)
 		return
 	}
 
 	if cgroupFallback {
-		containerID = readContainerID(cgroupPath)
-		if containerID != "" {
+		if id := readContainerID(cgroupPath); id != "" {
+			storeContainerID(id)
 			return
 		}
 
-		containerID = readMountinfo(selfMountInfoPath)
-		if containerID != "" {
+		if id := readMountinfo(selfMountInfoPath); id != "" {
+			storeContainerID(id)
 			return
 		}
 
 		// If we're in the host cgroup namespace, the cid should be retrievable in /proc/self/cgroup
 		// In private cgroup namespace, we can retrieve the cgroup controller inode.
-		if containerID == "" && isHostCgroupNs {
+		if isHostCgroupNs {
 			return
 		}
 
-		containerID = getCgroupInode(defaultCgroupMountPath, cgroupPath)
+		storeContainerID(getCgroupInode(defaultCgroupMountPath, cgroupPath))
 	}
 }

statsd/container_stub.go

@@ -10,8 +10,7 @@ func isHostCgroupNamespace() bool {
 var initContainerID = func(userProvidedID string, _, _ bool) {
 	initOnce.Do(func() {
 		if userProvidedID != "" {
-			containerID = userProvidedID
-			return
+			storeContainerID(userProvidedID)
 		}
 	})
 }

statsd/container_test.go

@@ -448,9 +448,9 @@ func TestReadCIDOrInode(t *testing.T) {
 
 	for _, tc := range tests {
 		t.Run(tc.description, func(t *testing.T) {
-			prevContainerID := containerID
+			prevContainerID := getContainerID()
 			defer func() {
-				containerID = prevContainerID
+				patchContainerID(prevContainerID)
 			}()
 
 			sysFsCgroupPath := path.Join(os.TempDir(), "sysfscgroup")
@@ -483,7 +483,7 @@ func TestReadCIDOrInode(t *testing.T) {
 			require.NoError(t, err)
 
 			readCIDOrInode("", procSelfCgroup.Name(), mountInfo.Name(), sysFsCgroupPath, true, tc.isHostCgroupNs)
-			require.Equal(t, expectedResult, containerID)
+			require.Equal(t, expectedResult, getContainerID())
 		})
 	}
 }