log: support --log-opt tag=

support a custom tag to add to each log for the container.

It is currently supported only by the journald backend.

Closes: https://github.com/containers/libpod/issues/3653

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

docs/source/markdown/podman-create.1.md

@@ -419,6 +419,17 @@ Logging driver specific options.  Used to set the path to the container log file
 
 `--log-opt path=/var/log/container/mycontainer.json`
 
+**--log-opt**=*tag*
+
+Set custom logging configuration.  Presently supports the `tag` option
+which specified a custom log tag for the container.  For example:
+
+`--log-opt tag="{{.ImageName}}"`
+
+It supports the same keys as `podman inspect --format`.
+
+It is currently supported only by the journald log driver.
+
 **--mac-address**=*address*
 
 Container MAC address (e.g. 92:d0:c6:0a:29:33)

docs/source/markdown/podman-run.1.md

@@ -426,10 +426,21 @@ Logging driver for the container.  Currently available options are *k8s-file* an
 
 **--log-opt**=*path*
 
-Logging driver specific options.  Used to set the path to the container log file.  For example:
+Set custom logging configuration.  Presently supports the `tag` option
+which specified a custom log tag for the container.  For example:
 
 `--log-opt path=/var/log/container/mycontainer.json`
 
+**--log-opt**=*tag*
+
+Specify a custom log tag for the container.  For example:
+
+`--log-opt tag="{{.ImageName}}"`
+
+It supports the same keys as `podman inspect --format`.
+
+It is currently supported only by the journald log driver.
+
 **--mac-address**=*address*
 
 Container MAC address (e.g. `92:d0:c6:0a:29:33`)

libpod/container.go

@@ -379,6 +379,8 @@ type ContainerConfig struct {
 	CgroupParent string `json:"cgroupParent"`
 	// LogPath log location
 	LogPath string `json:"logPath"`
+	// LogTag is the tag used for logging
+	LogTag string `json:"logTag"`
 	// LogDriver driver for logs
 	LogDriver string `json:"logDriver"`
 	// File containing the conmon PID
@@ -726,6 +728,11 @@ func (c *Container) LogPath() string {
 	return c.config.LogPath
 }
 
+// LogTag returns the tag to the container's log file
+func (c *Container) LogTag() string {
+	return c.config.LogTag
+}
+
 // RestartPolicy returns the container's restart policy.
 func (c *Container) RestartPolicy() string {
 	return c.config.RestartPolicy

libpod/container_inspect.go

@@ -107,6 +107,7 @@ type InspectContainerData struct {
 	OCIConfigPath   string                      `json:"OCIConfigPath,omitempty"`
 	OCIRuntime      string                      `json:"OCIRuntime,omitempty"`
 	LogPath         string                      `json:"LogPath"`
+	LogTag          string                      `json:"LogTag"`
 	ConmonPidFile   string                      `json:"ConmonPidFile"`
 	Name            string                      `json:"Name"`
 	RestartCount    int32                       `json:"RestartCount"`
@@ -629,17 +630,9 @@ type InspectNetworkSettings struct {
 	MacAddress             string               `json:"MacAddress"`
 }
 
-// Inspect a container for low-level information
-func (c *Container) Inspect(size bool) (*InspectContainerData, error) {
-	if !c.batched {
-		c.lock.Lock()
-		defer c.lock.Unlock()
-
-		if err := c.syncContainer(); err != nil {
-			return nil, err
-		}
-	}
-
+// inspectLocked inspects a container for low-level information.
+// The caller must held c.lock.
+func (c *Container) inspectLocked(size bool) (*InspectContainerData, error) {
 	storeCtr, err := c.runtime.store.Container(c.ID())
 	if err != nil {
 		return nil, errors.Wrapf(err, "error getting container from store %q", c.ID())
@@ -655,6 +648,20 @@ func (c *Container) Inspect(size bool) (*InspectContainerData, error) {
 	return c.getContainerInspectData(size, driverData)
 }
 
+// Inspect a container for low-level information
+func (c *Container) Inspect(size bool) (*InspectContainerData, error) {
+	if !c.batched {
+		c.lock.Lock()
+		defer c.lock.Unlock()
+
+		if err := c.syncContainer(); err != nil {
+			return nil, err
+		}
+	}
+
+	return c.inspectLocked(size)
+}
+
 func (c *Container) getContainerInspectData(size bool, driverData *driver.Data) (*InspectContainerData, error) {
 	config := c.config
 	runtimeInfo := c.state
@@ -732,6 +739,7 @@ func (c *Container) getContainerInspectData(size bool, driverData *driver.Data)
 		HostsPath:       hostsPath,
 		StaticDir:       config.StaticDir,
 		LogPath:         config.LogPath,
+		LogTag:          config.LogTag,
 		OCIRuntime:      config.OCIRuntime,
 		ConmonPidFile:   config.ConmonPidFile,
 		Name:            config.Name,

libpod/oci_conmon_linux.go

@@ -14,6 +14,7 @@ import (
 	"strconv"
 	"strings"
 	"syscall"
+	"text/template"
 	"time"
 
 	"github.com/containers/libpod/libpod/config"
@@ -532,7 +533,7 @@ func (r *ConmonOCIRuntime) ExecContainer(c *Container, sessionID string, options
 	if logrus.GetLevel() != logrus.DebugLevel && r.supportsJSON {
 		ociLog = c.execOCILog(sessionID)
 	}
-	args := r.sharedConmonArgs(c, sessionID, c.execBundlePath(sessionID), c.execPidPath(sessionID), c.execLogPath(sessionID), c.execExitFileDir(sessionID), ociLog)
+	args := r.sharedConmonArgs(c, sessionID, c.execBundlePath(sessionID), c.execPidPath(sessionID), c.execLogPath(sessionID), c.execExitFileDir(sessionID), ociLog, "")
 
 	if options.PreserveFDs > 0 {
 		args = append(args, formatRuntimeOpts("--preserve-fds", fmt.Sprintf("%d", options.PreserveFDs))...)
@@ -887,6 +888,27 @@ func waitPidStop(pid int, timeout time.Duration) error {
 	}
 }
 
+func (r *ConmonOCIRuntime) getLogTag(ctr *Container) (string, error) {
+	logTag := ctr.LogTag()
+	if logTag == "" {
+		return "", nil
+	}
+	data, err := ctr.inspectLocked(false)
+	if err != nil {
+		return "", nil
+	}
+	tmpl, err := template.New("container").Parse(logTag)
+	if err != nil {
+		return "", errors.Wrapf(err, "template parsing error %s", logTag)
+	}
+	var b bytes.Buffer
+	err = tmpl.Execute(&b, data)
+	if err != nil {
+		return "", err
+	}
+	return b.String(), nil
+}
+
 // createOCIContainer generates this container's main conmon instance and prepares it for starting
 func (r *ConmonOCIRuntime) createOCIContainer(ctr *Container, restoreOptions *ContainerCheckpointOptions) (err error) {
 	var stderrBuf bytes.Buffer
@@ -913,7 +935,13 @@ func (r *ConmonOCIRuntime) createOCIContainer(ctr *Container, restoreOptions *Co
 	if logrus.GetLevel() != logrus.DebugLevel && r.supportsJSON {
 		ociLog = filepath.Join(ctr.state.RunDir, "oci-log")
 	}
-	args := r.sharedConmonArgs(ctr, ctr.ID(), ctr.bundlePath(), filepath.Join(ctr.state.RunDir, "pidfile"), ctr.LogPath(), r.exitsDir, ociLog)
+
+	logTag, err := r.getLogTag(ctr)
+	if err != nil {
+		return err
+	}
+
+	args := r.sharedConmonArgs(ctr, ctr.ID(), ctr.bundlePath(), filepath.Join(ctr.state.RunDir, "pidfile"), ctr.LogPath(), r.exitsDir, ociLog, logTag)
 
 	if ctr.config.Spec.Process.Terminal {
 		args = append(args, "-t")
@@ -1147,7 +1175,7 @@ func (r *ConmonOCIRuntime) configureConmonEnv(runtimeDir string) ([]string, []*o
 }
 
 // sharedConmonArgs takes common arguments for exec and create/restore and formats them for the conmon CLI
-func (r *ConmonOCIRuntime) sharedConmonArgs(ctr *Container, cuuid, bundlePath, pidPath, logPath, exitDir, ociLogPath string) []string {
+func (r *ConmonOCIRuntime) sharedConmonArgs(ctr *Container, cuuid, bundlePath, pidPath, logPath, exitDir, ociLogPath, logTag string) []string {
 	// set the conmon API version to be able to use the correct sync struct keys
 	args := []string{"--api-version", "1"}
 	if r.cgroupManager == define.SystemdCgroupsManager && !ctr.config.NoCgroups {
@@ -1194,6 +1222,9 @@ func (r *ConmonOCIRuntime) sharedConmonArgs(ctr *Container, cuuid, bundlePath, p
 	if ociLogPath != "" {
 		args = append(args, "--runtime-arg", "--log-format=json", "--runtime-arg", "--log", fmt.Sprintf("--runtime-arg=%s", ociLogPath))
 	}
+	if logTag != "" {
+		args = append(args, "--log-tag", logTag)
+	}
 	if ctr.config.NoCgroups {
 		logrus.Debugf("Running with no CGroups")
 		args = append(args, "--runtime-arg", "--cgroup-manager", "--runtime-arg", "disabled")

libpod/options.go

@@ -1059,6 +1059,23 @@ func WithLogPath(path string) CtrCreateOption {
 	}
 }
 
+// WithLogTag sets the tag to the log file.
+func WithLogTag(tag string) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return define.ErrCtrFinalized
+		}
+		if tag == "" {
+			return errors.Wrapf(define.ErrInvalidArg, "log tag must be set")
+		}
+
+		ctr.config.LogTag = tag
+
+		return nil
+	}
+
+}
+
 // WithNoCgroups disables the creation of CGroups for the new container.
 func WithNoCgroups() CtrCreateOption {
 	return func(ctr *Container) error {

pkg/spec/createconfig.go

@@ -282,10 +282,13 @@ func (c *CreateConfig) getContainerCreateOptions(runtime *libpod.Runtime, pod *l
 	options = append(options, libpod.WithStopSignal(c.StopSignal))
 	options = append(options, libpod.WithStopTimeout(c.StopTimeout))
 
-	logPath := getLoggingPath(c.LogDriverOpt)
+	logPath, logTag := getLoggingOpts(c.LogDriverOpt)
 	if logPath != "" {
 		options = append(options, libpod.WithLogPath(logPath))
 	}
+	if logTag != "" {
+		options = append(options, libpod.WithLogTag(logTag))
+	}
 
 	if c.LogDriver != "" {
 		options = append(options, libpod.WithLogDriver(c.LogDriver))

pkg/spec/parse.go

@@ -132,16 +132,23 @@ func validateIOpsDevice(val string) (*throttleDevice, error) { //nolint
 	}, nil
 }
 
-func getLoggingPath(opts []string) string {
+// getLoggingOpts splits the path= and tag= options provided to --log-opt.
+func getLoggingOpts(opts []string) (string, string) {
+	var path, tag string
 	for _, opt := range opts {
 		arr := strings.SplitN(opt, "=", 2)
 		if len(arr) == 2 {
 			if strings.TrimSpace(arr[0]) == "path" {
-				return strings.TrimSpace(arr[1])
+				path = strings.TrimSpace(arr[1])
+			} else if strings.TrimSpace(arr[0]) == "tag" {
+				tag = strings.TrimSpace(arr[1])
 			}
 		}
+		if path != "" && tag != "" {
+			break
+		}
 	}
-	return ""
+	return path, tag
 }
 
 // ParseDevice parses device mapping string to a src, dest & permissions string

test/e2e/logs_test.go

@@ -1,7 +1,9 @@
 package integration
 
 import (
+	"fmt"
 	"os"
+	"os/exec"
 	"strings"
 
 	. "github.com/containers/libpod/test/utils"
@@ -153,6 +155,23 @@ var _ = Describe("Podman logs", func() {
 		Expect(results.ExitCode()).To(BeZero())
 	})
 
+	It("podman journald logs for container with container tag", func() {
+		Skip("need to verify images have correct packages for journald")
+		logc := podmanTest.Podman([]string{"run", "--log-driver", "journald", "--log-opt=tag={{.ImageName}}", "-d", ALPINE, "sh", "-c", "echo podman; sleep 0.1; echo podman; sleep 0.1; echo podman"})
+		logc.WaitWithDefaultTimeout()
+		Expect(logc.ExitCode()).To(Equal(0))
+		cid := logc.OutputToString()
+
+		wait := podmanTest.Podman([]string{"wait", "-l"})
+		wait.WaitWithDefaultTimeout()
+		Expect(wait.ExitCode()).To(BeZero())
+
+		cmd := exec.Command("journalctl", "--no-pager", "-o", "json", "--output-fields=CONTAINER_TAG", "-u", fmt.Sprintf("libpod-conmon-%s.scope", cid))
+		out, err := cmd.CombinedOutput()
+		Expect(err).To(BeNil())
+		Expect(string(out)).To(ContainSubstring("alpine"))
+	})
+
 	It("podman journald logs for container", func() {
 		Skip("need to verify images have correct packages for journald")
 		logc := podmanTest.Podman([]string{"run", "--log-driver", "journald", "-dt", ALPINE, "sh", "-c", "echo podman; echo podman; echo podman"})