[fluentd-gcp addon] Trim too long log entries due to Stackdriver limitation

test/e2e/instrumentation/logging/stackdrvier/basic.go

@@ -18,6 +18,7 @@ package stackdriver
 
 import (
 	"fmt"
+	"strings"
 	"time"
 
 	"k8s.io/apimachinery/pkg/util/wait"
@@ -107,6 +108,39 @@ var _ = instrumentation.SIGDescribe("Cluster level logging implemented by Stackd
 				err = utils.WaitForLogs(c, ingestionInterval, ingestionTimeout)
 				framework.ExpectNoError(err)
 			})
+
+			ginkgo.By("Checking that too long lines are trimmed", func() {
+				originalLength := 100001
+				cmd := []string{
+					"/bin/sh",
+					"-c",
+					fmt.Sprintf("while :; do printf '%%*s' %d | tr ' ' 'A'; echo; sleep 1; done", originalLength),
+				}
+				trimPrefix := "[Trimmed]"
+
+				pod, err := utils.StartAndReturnSelf(utils.NewExecLoggingPod("synthlogger-4", cmd), f)
+				framework.ExpectNoError(err, "Failed to start a pod")
+
+				ginkgo.By("Waiting for logs to ingest")
+				c := utils.NewLogChecker(p, func(_ string, logEntries []utils.LogEntry) (bool, error) {
+					if len(logEntries) == 0 {
+						return false, nil
+					}
+					log := logEntries[0]
+					if log.JSONPayload != nil {
+						return false, fmt.Errorf("got json log entry %v, wanted plain text", log.JSONPayload)
+					}
+					if len(log.TextPayload) == originalLength {
+						return false, fmt.Errorf("got non-trimmed entry of length %d", len(log.TextPayload))
+					}
+					if !strings.HasPrefix(log.TextPayload, trimPrefix) {
+						return false, fmt.Errorf("got message without prefix '%s': %s", trimPrefix, log.TextPayload)
+					}
+					return true, nil
+				}, utils.JustTimeout, pod.Name())
+				err = utils.WaitForLogs(c, ingestionInterval, ingestionTimeout)
+				framework.ExpectNoError(err)
+			})
 		})
 	})