support linkerd (#547)

* support linkerd - initial commit

* renaming readEnvironmentVariable

tap/source/discoverer_util.go

@@ -0,0 +1,38 @@
+package source
+
+import (
+	"io/ioutil"
+	"regexp"
+	"strings"
+
+	"github.com/up9inc/mizu/shared/logger"
+)
+
+var numberRegex = regexp.MustCompile("[0-9]+")
+
+func getSingleValueFromEnvironmentVariableFile(filePath string, variableName string) (string, error) {
+	bytes, err := ioutil.ReadFile(filePath)
+
+	if err != nil {
+		logger.Log.Warningf("Error reading environment file %v - %v", filePath, err)
+		return "", err
+	}
+
+	envs := strings.Split(string(bytes), string([]byte{0}))
+
+	for _, env := range envs {
+		if !strings.Contains(env, "=") {
+			continue
+		}
+
+		parts := strings.Split(env, "=")
+		varName := parts[0]
+		value := parts[1]
+
+		if variableName == varName {
+			return value, nil
+		}
+	}
+
+	return "", nil
+}

tap/source/envoy_discoverer.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
-	"regexp"
 	"strings"
 
 	"github.com/up9inc/mizu/shared/logger"
@@ -13,8 +12,6 @@ import (
 
 const envoyBinary = "/envoy"
 
-var numberRegex = regexp.MustCompile("[0-9]+")
-
 func discoverRelevantEnvoyPids(procfs string, pods []v1.Pod) ([]string, error) {
 	result := make([]string, 0)
 
@@ -36,7 +33,7 @@ func discoverRelevantEnvoyPids(procfs string, pods []v1.Pod) ([]string, error) {
 			continue
 		}
 
-		if checkPid(procfs, pid.Name(), pods) {
+		if checkEnvoyPid(procfs, pid.Name(), pods) {
 			result = append(result, pid.Name())
 		}
 	}
@@ -46,7 +43,7 @@ func discoverRelevantEnvoyPids(procfs string, pods []v1.Pod) ([]string, error) {
 	return result, nil
 }
 
-func checkPid(procfs string, pid string, pods []v1.Pod) bool {
+func checkEnvoyPid(procfs string, pid string, pods []v1.Pod) bool {
 	execLink := fmt.Sprintf("%v/%v/exe", procfs, pid)
 	exec, err := os.Readlink(execLink)
 
@@ -63,7 +60,7 @@ func checkPid(procfs string, pid string, pods []v1.Pod) bool {
 	}
 
 	environmentFile := fmt.Sprintf("%v/%v/environ", procfs, pid)
-	podIp, err := readEnvironmentVariable(environmentFile, "INSTANCE_IP")
+	podIp, err := getSingleValueFromEnvironmentVariableFile(environmentFile, "INSTANCE_IP")
 
 	if err != nil {
 		return false
@@ -84,30 +81,3 @@ func checkPid(procfs string, pid string, pods []v1.Pod) bool {
 
 	return false
 }
-
-func readEnvironmentVariable(file string, name string) (string, error) {
-	bytes, err := ioutil.ReadFile(file)
-
-	if err != nil {
-		logger.Log.Warningf("Error reading environment file %v - %v", file, err)
-		return "", err
-	}
-
-	envs := strings.Split(string(bytes), string([]byte{0}))
-
-	for _, env := range envs {
-		if !strings.Contains(env, "=") {
-			continue
-		}
-
-		parts := strings.Split(env, "=")
-		varName := parts[0]
-		value := parts[1]
-
-		if name == varName {
-			return value, nil
-		}
-	}
-
-	return "", nil
-}

tap/source/linkerd_discoverer.go

@@ -0,0 +1,83 @@
+package source
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/up9inc/mizu/shared/logger"
+	v1 "k8s.io/api/core/v1"
+)
+
+const linkerdBinary = "/linkerd2-proxy"
+
+func discoverRelevantLinkerdPids(procfs string, pods []v1.Pod) ([]string, error) {
+	result := make([]string, 0)
+
+	pids, err := ioutil.ReadDir(procfs)
+
+	if err != nil {
+		return result, err
+	}
+
+	logger.Log.Infof("Starting linkerd auto discoverer %v %v - scanning %v potential pids",
+		procfs, pods, len(pids))
+
+	for _, pid := range pids {
+		if !pid.IsDir() {
+			continue
+		}
+
+		if !numberRegex.MatchString(pid.Name()) {
+			continue
+		}
+
+		if checkLinkerdPid(procfs, pid.Name(), pods) {
+			result = append(result, pid.Name())
+		}
+	}
+
+	logger.Log.Infof("Found %v relevant linkerd processes - %v", len(result), result)
+
+	return result, nil
+}
+
+func checkLinkerdPid(procfs string, pid string, pods []v1.Pod) bool {
+	execLink := fmt.Sprintf("%v/%v/exe", procfs, pid)
+	exec, err := os.Readlink(execLink)
+
+	if err != nil {
+		// Debug on purpose - it may happen due to many reasons and we only care
+		//	for it during troubleshooting
+		//
+		logger.Log.Debugf("Unable to read link %v - %v\n", execLink, err)
+		return false
+	}
+
+	if !strings.HasSuffix(exec, linkerdBinary) {
+		return false
+	}
+
+	environmentFile := fmt.Sprintf("%v/%v/environ", procfs, pid)
+	podName, err := getSingleValueFromEnvironmentVariableFile(environmentFile, "_pod_name")
+
+	if err != nil {
+		return false
+	}
+
+	if podName == "" {
+		logger.Log.Debugf("Found a linkerd process without _pod_name variable %v\n", pid)
+		return false
+	}
+
+	logger.Log.Infof("Found linkerd pid %v with pod name %v", pid, podName)
+
+	for _, pod := range pods {
+		if pod.Name == podName {
+			return true
+		}
+	}
+
+	return false
+}

tap/source/packet_source_manager.go

@@ -16,7 +16,7 @@ type PacketSourceManager struct {
 }
 
 func NewPacketSourceManager(procfs string, pids string, filename string, interfaceName string,
-	istio bool, pods []v1.Pod, behaviour TcpPacketSourceBehaviour) (*PacketSourceManager, error) {
+	mtls bool, pods []v1.Pod, behaviour TcpPacketSourceBehaviour) (*PacketSourceManager, error) {
 	sources := make([]*tcpPacketSource, 0)
 	sources, err := createHostSource(sources, filename, interfaceName, behaviour)
 
@@ -25,7 +25,8 @@ func NewPacketSourceManager(procfs string, pids string, filename string, interfa
 	}
 
 	sources = createSourcesFromPids(sources, procfs, pids, interfaceName, behaviour)
-	sources = createSourcesFromEnvoy(sources, istio, procfs, pods, interfaceName, behaviour)
+	sources = createSourcesFromEnvoy(sources, mtls, procfs, pods, interfaceName, behaviour)
+	sources = createSourcesFromLinkerd(sources, mtls, procfs, pods, interfaceName, behaviour)
 
 	return &PacketSourceManager{
 		sources: sources,
@@ -54,13 +55,13 @@ func createSourcesFromPids(sources []*tcpPacketSource, procfs string, pids strin
 	return sources
 }
 
-func createSourcesFromEnvoy(sources []*tcpPacketSource, istio bool, procfs string, clusterIps []v1.Pod,
+func createSourcesFromEnvoy(sources []*tcpPacketSource, mtls bool, procfs string, pods []v1.Pod,
 	interfaceName string, behaviour TcpPacketSourceBehaviour) []*tcpPacketSource {
-	if !istio {
+	if !mtls {
 		return sources
 	}
 
-	envoyPids, err := discoverRelevantEnvoyPids(procfs, clusterIps)
+	envoyPids, err := discoverRelevantEnvoyPids(procfs, pods)
 
 	if err != nil {
 		logger.Log.Warningf("Unable to discover envoy pids - %v", err)
@@ -73,6 +74,25 @@ func createSourcesFromEnvoy(sources []*tcpPacketSource, istio bool, procfs strin
 	return sources
 }
 
+func createSourcesFromLinkerd(sources []*tcpPacketSource, mtls bool, procfs string, pods []v1.Pod,
+	interfaceName string, behaviour TcpPacketSourceBehaviour) []*tcpPacketSource {
+	if !mtls {
+		return sources
+	}
+
+	linkerdPids, err := discoverRelevantLinkerdPids(procfs, pods)
+
+	if err != nil {
+		logger.Log.Warningf("Unable to discover linkerd pids - %v", err)
+		return sources
+	}
+
+	netnsSources := newNetnsPacketSources(procfs, linkerdPids, interfaceName, behaviour)
+	sources = append(sources, netnsSources...)
+
+	return sources
+}
+
 func newHostPacketSource(filename string, interfaceName string,
 	behaviour TcpPacketSourceBehaviour) (*tcpPacketSource, error) {
 	var name string