Support structured logging

Makefile

@@ -16,3 +16,9 @@ CMDS=livenessprobe
 all: build
 
 include release-tools/build.make
+
+# Check contextual logging.
+.PHONY: logcheck
+test: logcheck
+logcheck:
+	hack/verify-logcheck.sh

cmd/livenessprobe/main.go

@@ -22,7 +22,6 @@ import (
 	"fmt"
 	"net"
 	"net/http"
-	"os"
 	"time"
 
 	"k8s.io/klog/v2"
@@ -58,36 +57,37 @@ type healthProbe struct {
 
 func (h *healthProbe) checkProbe(w http.ResponseWriter, req *http.Request) {
 	ctx, cancel := context.WithTimeout(req.Context(), *probeTimeout)
+	logger := klog.FromContext(ctx)
 	defer cancel()
 
 	conn, err := connlib.Connect(*csiAddress, h.metricsManager, connlib.WithTimeout(*probeTimeout))
 	if err != nil {
 		w.WriteHeader(http.StatusInternalServerError)
 		w.Write([]byte(err.Error()))
-		klog.ErrorS(err, "Failed to establish connection to CSI driver")
+		logger.Error(err, "Failed to establish connection to CSI driver")
 		return
 	}
 	defer conn.Close()
 
-	klog.V(5).InfoS("Sending probe request to CSI driver", "driver", h.driverName)
+	logger.V(5).Info("Sending probe request to CSI driver", "driver", h.driverName)
 	ready, err := rpc.Probe(ctx, conn)
 	if err != nil {
 		w.WriteHeader(http.StatusInternalServerError)
 		w.Write([]byte(err.Error()))
-		klog.ErrorS(err, "Health check failed")
+		logger.Error(err, "Health check failed")
 		return
 	}
 
 	if !ready {
 		w.WriteHeader(http.StatusInternalServerError)
 		w.Write([]byte("driver responded but is not ready"))
-		klog.ErrorS(nil, "Driver responded but is not ready")
+		logger.Error(nil, "Driver responded but is not ready")
 		return
 	}
 
 	w.WriteHeader(http.StatusOK)
 	w.Write([]byte(`ok`))
-	klog.V(5).InfoS("Health check succeeded")
+	logger.V(5).Info("Health check succeeded")
 }
 
 func main() {
@@ -97,18 +97,19 @@ func main() {
 	logsapi.AddGoFlags(c, flag.CommandLine)
 	logs.InitLogs()
 	flag.Parse()
+	logger := klog.Background()
 	if err := logsapi.ValidateAndApply(c, fg); err != nil {
-		klog.ErrorS(err, "LoggingConfiguration is invalid")
-		os.Exit(1)
+		logger.Error(err, "LoggingConfiguration is invalid")
+		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
 
 	if *healthzPort != defaultHealthzPort && *httpEndpoint != "" {
-		klog.ErrorS(nil, "Only one of `--health-port` and `--http-endpoint` can be explicitly set")
-		os.Exit(1)
+		logger.Error(nil, "Only one of `--health-port` and `--http-endpoint` can be explicitly set")
+		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
 	if *metricsAddress != "" && *httpEndpoint != "" {
-		klog.ErrorS(nil, "Only one of `--metrics-address` and `--http-endpoint` can be explicitly set")
-		os.Exit(1)
+		logger.Error(nil, "Only one of `--metrics-address` and `--http-endpoint` can be explicitly set")
+		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
 	var addr string
 	if *httpEndpoint != "" {
@@ -126,19 +127,19 @@ func main() {
 	if err != nil {
 		// connlib should retry forever so a returned error should mean
 		// the grpc client is misconfigured rather than an error on the network or CSI driver.
-		klog.ErrorS(err, "Failed to establish connection to CSI driver")
+		logger.Error(err, "Failed to establish connection to CSI driver")
 		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
 
-	klog.InfoS("Calling CSI driver to discover driver name")
+	logger.Info("Calling CSI driver to discover driver name")
 	csiDriverName, err := rpc.GetDriverName(context.Background(), csiConn)
 	csiConn.Close()
 	if err != nil {
 		// The CSI driver does not support GetDriverName, which is serious enough to crash the probe.
-		klog.ErrorS(err, "Failed to get CSI driver name")
+		logger.Error(err, "Failed to get CSI driver name")
 		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
-	klog.InfoS("CSI driver name", "driver", csiDriverName)
+	logger.Info("CSI driver name", "driver", csiDriverName)
 
 	hp := &healthProbe{
 		driverName:     csiDriverName,
@@ -157,19 +158,19 @@ func main() {
 		metricsMux := http.NewServeMux()
 		metricsManager.RegisterToServer(metricsMux, *metricsPath)
 		go func() {
-			klog.InfoS("Separate metrics ServeMux listening", "address", *metricsAddress)
+			logger.Info("Separate metrics ServeMux listening", "address", *metricsAddress)
 			err := http.ListenAndServe(*metricsAddress, metricsMux)
 			if err != nil {
-				klog.ErrorS(err, "Failed to start prometheus metrics endpoint on specified address and path", "addr", *metricsAddress, "path", *metricsPath)
+				logger.Error(err, "Failed to start prometheus metrics endpoint on specified address and path", "addr", *metricsAddress, "path", *metricsPath)
 				klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 			}
 		}()
 	}
 
 	mux.HandleFunc("/healthz", hp.checkProbe)
-	klog.InfoS("ServeMux listening", "address", addr)
+	logger.Info("ServeMux listening", "address", addr)
 	err = http.ListenAndServe(addr, mux)
 	if err != nil {
-		klog.ErrorS(err, "Failed to start http server")
+		logger.Error(err, "Failed to start http server")
 	}
 }

hack/verify-logcheck.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+
+# Copyright 2024 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script uses the logcheck tool to analyze the source code
+# for proper usage of klog contextual logging.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+LOGCHECK_VERSION=${1:-0.8.1}
+
+# This will canonicalize the path
+LIVENESSPROBE_ROOT=$(cd "$(dirname "${BASH_SOURCE[0]}")"/.. && pwd -P)
+
+# Create a temporary directory for installing logcheck and
+# set up a trap command to remove it when the script exits.
+LIVENESSPROBE_TEMP=$(mktemp -d 2>/dev/null || mktemp -d -t livenessprobe.XXXXXX)
+trap 'rm -rf "${LIVENESSPROBE_TEMP}"' EXIT
+
+echo "Installing logcheck to temp dir: sigs.k8s.io/logtools/logcheck@v${LOGCHECK_VERSION}"
+GOBIN="${LIVENESSPROBE_TEMP}" go install "sigs.k8s.io/logtools/logcheck@v${LOGCHECK_VERSION}"
+echo "Verifing logcheck: ${LIVENESSPROBE_TEMP}/logcheck -check-contextual ${LIVENESSPROBE_ROOT}/..."
+"${LIVENESSPROBE_TEMP}/logcheck" -check-contextual "${LIVENESSPROBE_ROOT}/..."