fix: e2e failure for online upgrade test cases (cloudnative-pg#364)

Signed-off-by: Tao Li <tao.li@enterprisedb.com>

Author: litaocdl

pkg/management/postgres/instance.go

@@ -396,7 +396,7 @@ func (instance *Instance) Reload() error {
 // Run this instance returning an OS process needed
 // to control the instance execution
 func (instance Instance) Run() (*execlog.StreamingCmd, error) {
-	process, err := instance.CheckForExistingPostmaster(postgresName)
+	process, err := instance.CheckForExistingPostmaster()
 	if err != nil {
 		return nil, err
 	}

pkg/management/postgres/pidfile.go

@@ -39,16 +39,16 @@ const PostgresqlPidFile = "postmaster.pid" //wokeignore:rule=master
 // directory and check the existence of the relative process. If the
 // process exists, then that process entry is returned.
 // If it doesn't exist then the PID file is stale and is removed.
-func (instance *Instance) CheckForExistingPostmaster(postgresExecutable string) (*os.Process, error) {
+func (instance *Instance) CheckForExistingPostmaster() (*os.Process, error) {
 	pidFile := path.Join(instance.PgData, PostgresqlPidFile)
 	contextLog := log.WithValues("file", pidFile)
 	pidFileContents, pid, err := instance.GetPostmasterPidFromFile(pidFile)
 	if err != nil {
 		// The content of the PID file is wrong.
 		// In this case we just remove the PID file, which is assumed
 		// to be stale, and continue our work
-		contextLog.Info("The PID file content is wrong, deleting it and assuming it's stale")
-		contextLog.Debug("PID file", "contents", pidFileContents)
+		contextLog.Info("The PID file content is wrong, deleting it and assuming it's stale",
+			"err", err, "pidFileContents", pidFileContents)
 		return nil, instance.CleanUpStalePid()
 	}
 
@@ -60,15 +60,14 @@ func (instance *Instance) CheckForExistingPostmaster(postgresExecutable string)
 	}
 	if process == nil {
 		// The process doesn't exist and this PID file is stale
-		contextLog.Info("The PID file is stale, deleting it")
-		contextLog.Debug("PID file", "contents", pidFileContents)
+		contextLog.Info("The PID file is stale, deleting it", "pidFileContents", pidFileContents)
 		return nil, instance.CleanUpStalePid()
 	}
 
-	if process.Executable() != postgresExecutable {
+	if process.Executable() != postgresName {
 		// The process is not running PostgreSQL and this PID file is stale
-		contextLog.Info("The PID file is stale (executable mismatch), deleting it")
-		contextLog.Debug("PID file", "contents", pidFileContents)
+		contextLog.Info("The PID file is stale (executable mismatch), deleting it",
+			"pidFileContents", pidFileContents, "postgresExecutable", process.Executable())
 		return nil, instance.CleanUpStalePid()
 	}
 

pkg/management/postgres/pidfile_test.go

@@ -22,8 +22,6 @@ import (
 	"os"
 	"path/filepath"
 
-	"github.com/mitchellh/go-ps"
-
 	"github.com/cloudnative-pg/cloudnative-pg/pkg/fileutils"
 
 	. "github.com/onsi/ginkgo/v2"
@@ -51,7 +49,7 @@ var _ = Describe("the detection of a postmaster process using the pid file", fun
 		instance := NewInstance()
 		instance.PgData = pgdata
 		instance.SocketDirectory = socketDir
-		process, err := instance.CheckForExistingPostmaster(postgresName)
+		process, err := instance.CheckForExistingPostmaster()
 		Expect(err).ShouldNot(HaveOccurred())
 		Expect(process).To(BeNil())
 	})
@@ -69,7 +67,7 @@ var _ = Describe("the detection of a postmaster process using the pid file", fun
 		err = ioutil.WriteFile(filepath.Join(socketDir, ".s.PGSQL.5432.lock"), []byte("1234"), 0o400)
 		Expect(err).ShouldNot(HaveOccurred())
 
-		process, err := instance.CheckForExistingPostmaster(postgresName)
+		process, err := instance.CheckForExistingPostmaster()
 		Expect(err).ShouldNot(HaveOccurred())
 		Expect(process).To(BeNil())
 
@@ -91,12 +89,10 @@ var _ = Describe("the detection of a postmaster process using the pid file", fun
 			filepath.Join(pgdata, PostgresqlPidFile),
 			[]byte(fmt.Sprintf("%v", myPid)), 0o400)
 		Expect(err).ShouldNot(HaveOccurred())
-		myProcess, err := ps.FindProcess(myPid)
-		Expect(err).ShouldNot(HaveOccurred())
-		myExecutable := myProcess.Executable()
 
-		process, err := instance.CheckForExistingPostmaster(myExecutable)
+		process, err := instance.CheckForExistingPostmaster()
 		Expect(err).ShouldNot(HaveOccurred())
-		Expect(process).ToNot(BeNil())
+		// to be null because executable file name is not postgres
+		Expect(process).To(BeNil())
 	})
 })