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This removes the CGO deps and makes for a completely static Go binary. The downside is that is fork/execs a binary to get to the logs. It supports the same options as the current impl. A thing that's different is the time/date output which doesn't match up. No real intentation to get this merged (current binary runs on RH8 which I care about atm), but also don't want to loose the code as there were some tricky bits about tailing the logs and not creating zombie journalctls. See #84 Signed-off-by: Miek Gieben <miek@miek.nl>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,119 @@ | ||
| package provider | ||
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| import ( | ||
| "bufio" | ||
| "errors" | ||
| "fmt" | ||
| "io" | ||
| "os/exec" | ||
| "strings" | ||
| "time" | ||
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| nodeapi "github.com/virtual-kubelet/virtual-kubelet/node/api" | ||
| ) | ||
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| const journalctl = "journalctl" | ||
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| func journalReader(namespace, name, container string, logOpts nodeapi.ContainerLogOpts) (io.ReadCloser, func() error, error) { | ||
| fnlog := log. | ||
| WithField("podNamespace", namespace). | ||
| WithField("podName", name). | ||
| WithField("containerName", container) | ||
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| fnlog.Infof("calling for container logs with options %+v", logOpts) | ||
| cancel := func() error { return nil } // initialize as noop | ||
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| unitName := strings.Join([]string{unitPrefix(namespace, name), container, "service"}, separator) | ||
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| // Handle all the options. | ||
| args := []string{"-u", unitName, "--no-hostname"} // only works with -o short-xxx options. | ||
| if logOpts.Tail > 0 { | ||
| args = append(args, "-n") | ||
| args = append(args, fmt.Sprintf("%d", logOpts.Tail)) | ||
| } | ||
| if logOpts.Follow { | ||
| args = append(args, "-f") | ||
| } | ||
| if !logOpts.Timestamps { | ||
| args = append(args, "-o") | ||
| args = append(args, "cat") | ||
| } else { | ||
| args = append(args, "-o") | ||
| args = append(args, "short-full") // this is _not_ the default Go timestamp output | ||
| } | ||
| if logOpts.SinceSeconds > 0 { | ||
| args = append(args, "-S") | ||
| args = append(args, fmt.Sprintf("-%ds", logOpts.SinceSeconds)) | ||
| } | ||
| if !logOpts.SinceTime.IsZero() { | ||
| args = append(args, "-S") | ||
| args = append(args, logOpts.SinceTime.Format(time.RFC3339)) | ||
| } | ||
| // Previous might not be possible to implement | ||
| // TODO(pires,miek) show logs from the current Pod alone https://github.com/virtual-kubelet/systemk/issues/5#issuecomment-765278538 | ||
| // LimitBytes - unsure (maybe a io.CopyBuffer?) | ||
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| fnlog.Debugf("getting container logs via: %q %v", journalctl, args) | ||
| cmd := exec.Command(journalctl, args...) | ||
| p, err := cmd.StdoutPipe() | ||
| if err != nil { | ||
| return nil, cancel, err | ||
| } | ||
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| if err := cmd.Start(); err != nil { | ||
| return nil, cancel, err | ||
| } | ||
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| cancel = func() error { | ||
| go func() { | ||
| if err := cmd.Wait(); err != nil { | ||
| fnlog.Debugf("wait for %q failed: %s", journalctl, err) | ||
| } | ||
| }() | ||
| return cmd.Process.Kill() | ||
| } | ||
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| return p, cancel, nil | ||
| } | ||
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| var ErrExpired = errors.New("timeout expired") | ||
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| // journalFollow synchronously follows the io.Reader, writing each new journal entry to writer. The | ||
| // follow will continue until a single time.Time is received on the until channel (or it's closed). | ||
| func journalFollow(until <-chan time.Time, reader io.Reader, writer io.Writer) error { | ||
| scanner := bufio.NewScanner(reader) | ||
| bufch := make(chan []byte) | ||
| errch := make(chan error) | ||
|
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| go func() { | ||
| for scanner.Scan() { | ||
| if err := scanner.Err(); err != nil { | ||
| errch <- err | ||
| return | ||
| } | ||
| bufch <- scanner.Bytes() | ||
| } | ||
| // When the context is Done() the 'until' channel is closed, this kicks in the defers in the GetContainerLogsHandler method. | ||
| // this cleans up the journalctl, and closes all file descripters. Scan() then stops with an error (before any reads, | ||
| // hence the above if err .. .isn't triggered). In the end this go-routine exits. | ||
| // the error here is "read |0: file already closed". | ||
| }() | ||
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| for { | ||
| select { | ||
| case <-until: | ||
| return ErrExpired | ||
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| case err := <-errch: | ||
| return err | ||
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| case buf := <-bufch: | ||
| if _, err := writer.Write(buf); err != nil { | ||
| return err | ||
| } | ||
| if _, err := io.WriteString(writer, "\n"); err != nil { | ||
| return err | ||
| } | ||
| } | ||
| } | ||
| } |
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