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>

4 files changed, 77 insertions, 14 deletions

diff --git a/libpod/container.go b/libpod/container.go
index edf72f4ee..a046dcafc 100644
--- a/libpod/container.go
+++ b/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
diff --git a/libpod/container_inspect.go b/libpod/container_inspect.go
index 639dd6e91..3f4ab394f 100644
--- a/libpod/container_inspect.go
+++ b/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,
diff --git a/libpod/oci_conmon_linux.go b/libpod/oci_conmon_linux.go
index 0312f0ba2..d4bdabaf5 100644
--- a/libpod/oci_conmon_linux.go
+++ b/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")
diff --git a/libpod/options.go b/libpod/options.go
index 031f4f705..1d6863e7b 100644
--- a/libpod/options.go
+++ b/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 {