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package pidfile // import "github.com/docker/docker/pkg/pidfile"
import (
"errors"
"os"
"os/exec"
"path/filepath"
"runtime"
"strconv"
"testing"
)
func TestWrite(t *testing.T) {
path := filepath.Join(t.TempDir(), "testfile")
err := Write(path, 0)
if err == nil {
t.Fatal("writing PID < 1 should fail")
}
err = Write(path, os.Getpid())
if err != nil {
t.Fatal("Could not create test file", err)
}
err = Write(path, os.Getpid())
if err == nil {
t.Error("Test file creation not blocked")
}
pid, err := Read(path)
if err != nil {
t.Error(err)
}
if pid != os.Getpid() {
t.Errorf("expected pid %d, got %d", os.Getpid(), pid)
}
}
func TestRead(t *testing.T) {
tmpDir := t.TempDir()
t.Run("non-existing pidFile", func(t *testing.T) {
_, err := Read(filepath.Join(tmpDir, "nosuchfile"))
if !errors.Is(err, os.ErrNotExist) {
t.Errorf("expected an os.ErrNotExist, got: %+v", err)
}
})
// Verify that we ignore a malformed PID in the file.
t.Run("malformed pid", func(t *testing.T) {
// Not using Write here, to test Read in isolation.
pidFile := filepath.Join(tmpDir, "pidfile-malformed")
err := os.WriteFile(pidFile, []byte("something that's not an integer"), 0o644)
if err != nil {
t.Fatal(err)
}
pid, err := Read(pidFile)
if err != nil {
t.Error(err)
}
if pid != 0 {
t.Errorf("expected pid %d, got %d", 0, pid)
}
})
t.Run("zero pid", func(t *testing.T) {
// Not using Write here, to test Read in isolation.
pidFile := filepath.Join(tmpDir, "pidfile-zero")
err := os.WriteFile(pidFile, []byte(strconv.Itoa(0)), 0o644)
if err != nil {
t.Fatal(err)
}
pid, err := Read(pidFile)
if err != nil {
t.Error(err)
}
if pid != 0 {
t.Errorf("expected pid %d, got %d", 0, pid)
}
})
t.Run("negative pid", func(t *testing.T) {
// Not using Write here, to test Read in isolation.
pidFile := filepath.Join(tmpDir, "pidfile-negative")
err := os.WriteFile(pidFile, []byte(strconv.Itoa(-1)), 0o644)
if err != nil {
t.Fatal(err)
}
pid, err := Read(pidFile)
if err != nil {
t.Error(err)
}
if pid != 0 {
t.Errorf("expected pid %d, got %d", 0, pid)
}
})
t.Run("current process pid", func(t *testing.T) {
// Not using Write here, to test Read in isolation.
pidFile := filepath.Join(tmpDir, "pidfile")
err := os.WriteFile(pidFile, []byte(strconv.Itoa(os.Getpid())), 0o644)
if err != nil {
t.Fatal(err)
}
pid, err := Read(pidFile)
if err != nil {
t.Error(err)
}
if pid != os.Getpid() {
t.Errorf("expected pid %d, got %d", os.Getpid(), pid)
}
})
// Verify that we don't return a PID if the process exited.
t.Run("exited process", func(t *testing.T) {
if runtime.GOOS == "windows" {
t.Skip("TODO: make this work on Windows")
}
// Get a PID of an exited process.
cmd := exec.Command("echo", "hello world")
err := cmd.Run()
if err != nil {
t.Fatal(err)
}
exitedPID := cmd.ProcessState.Pid()
// Not using Write here, to test Read in isolation.
pidFile := filepath.Join(tmpDir, "pidfile-exited")
err = os.WriteFile(pidFile, []byte(strconv.Itoa(exitedPID)), 0o644)
if err != nil {
t.Fatal(err)
}
pid, err := Read(pidFile)
if err != nil {
t.Error(err)
}
if pid != 0 {
t.Errorf("expected pid %d, got %d", 0, pid)
}
})
}
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