logging: new mode -l passthrough

it allows to pass the current std streams down to the container.

conmon support: containers/conmon#289

[NO TESTS NEEDED] it needs a new conmon.

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

cmd/podman/common/completion.go

@@ -780,7 +780,7 @@ func AutocompleteImageVolume(cmd *cobra.Command, args []string, toComplete strin
 // -> "journald", "none", "k8s-file"
 func AutocompleteLogDriver(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 	// don't show json-file
-	logDrivers := []string{define.JournaldLogging, define.NoLogging, define.KubernetesLogging}
+	logDrivers := []string{define.JournaldLogging, define.NoLogging, define.KubernetesLogging, define.PassthroughLogging}
 	return logDrivers, cobra.ShellCompDirectiveNoFileComp
 }
 

cmd/podman/containers/create.go

@@ -161,7 +161,9 @@ func create(cmd *cobra.Command, args []string) error {
 		}
 	}
 
-	fmt.Println(report.Id)
+	if cliVals.LogDriver != define.PassthroughLogging {
+		fmt.Println(report.Id)
+	}
 	return nil
 }
 
@@ -188,6 +190,9 @@ func CreateInit(c *cobra.Command, vals entities.ContainerCreateOptions, isInfra
 			vals.UserNS = "private"
 		}
 	}
+	if registry.IsRemote() && cliVals.LogDriver == define.PassthroughLogging {
+		return vals, errors.New("the '--log-driver passthrough' option is not supported in remote mode")
+	}
 
 	if !isInfra {
 		if c.Flag("shm-size").Changed {

cmd/podman/containers/run.go

@@ -200,7 +200,7 @@ func run(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	if runOpts.Detach {
+	if runOpts.Detach && cliVals.LogDriver != define.PassthroughLogging {
 		fmt.Println(report.Id)
 		return nil
 	}

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

@@ -513,7 +513,7 @@ Not implemented
 
 #### **--log-driver**="*k8s-file*"
 
-Logging driver for the container. Currently available options are *k8s-file*, *journald*, and *none*, with *json-file* aliased to *k8s-file* for scripting compatibility.
+Logging driver for the container. Currently available options are *k8s-file*, *journald*, *none* and *passthrough*, with *json-file* aliased to *k8s-file* for scripting compatibility.
 
 #### **--log-opt**=*name*=*value*
 

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

@@ -538,7 +538,7 @@ Not implemented.
 
 #### **--log-driver**="*driver*"
 
-Logging driver for the container. Currently available options are **k8s-file**, **journald**, and **none**, with **json-file** aliased to **k8s-file** for scripting compatibility.
+Logging driver for the container. Currently available options are **k8s-file**, **journald**, **none** and **passthrough**, with **json-file** aliased to **k8s-file** for scripting compatibility.
 
 #### **--log-opt**=*name*=*value*
 

libpod/container_api.go

@@ -229,6 +229,10 @@ func (c *Container) Kill(signal uint) error {
 // This function returns when the attach finishes. It does not hold the lock for
 // the duration of its runtime, only using it at the beginning to verify state.
 func (c *Container) Attach(streams *define.AttachStreams, keys string, resize <-chan define.TerminalSize) error {
+	switch c.LogDriver() {
+	case define.PassthroughLogging:
+		return errors.Wrapf(define.ErrNoLogs, "this container is using the 'passthrough' log driver, cannot attach")
+	}
 	if !c.batched {
 		c.lock.Lock()
 		if err := c.syncContainer(); err != nil {

libpod/container_log.go

@@ -18,7 +18,7 @@ import (
 var logDrivers []string
 
 func init() {
-	logDrivers = append(logDrivers, define.KubernetesLogging, define.NoLogging)
+	logDrivers = append(logDrivers, define.KubernetesLogging, define.NoLogging, define.PassthroughLogging)
 }
 
 // Log is a runtime function that can read one or more container logs.
@@ -34,6 +34,8 @@ func (r *Runtime) Log(ctx context.Context, containers []*Container, options *log
 // ReadLog reads a containers log based on the input options and returns log lines over a channel.
 func (c *Container) ReadLog(ctx context.Context, options *logs.LogOptions, logChannel chan *logs.LogLine) error {
 	switch c.LogDriver() {
+	case define.PassthroughLogging:
+		return errors.Wrapf(define.ErrNoLogs, "this container is using the 'passthrough' log driver, cannot read logs")
 	case define.NoLogging:
 		return errors.Wrapf(define.ErrNoLogs, "this container is using the 'none' log driver, cannot read logs")
 	case define.JournaldLogging:

libpod/define/config.go

@@ -78,6 +78,9 @@ const JSONLogging = "json-file"
 // NoLogging is the string conmon expects when specifying to use no log driver whatsoever
 const NoLogging = "none"
 
+// PassthroughLogging is the string conmon expects when specifying to use the passthrough driver
+const PassthroughLogging = "passthrough"
+
 // Strings used for --sdnotify option to podman
 const (
 	SdNotifyModeContainer = "container"

libpod/oci_conmon_linux.go

@@ -1285,6 +1285,8 @@ func (r *ConmonOCIRuntime) sharedConmonArgs(ctr *Container, cuuid, bundlePath, p
 		logDriverArg = define.JournaldLogging
 	case define.NoLogging:
 		logDriverArg = define.NoLogging
+	case define.PassthroughLogging:
+		logDriverArg = define.PassthroughLogging
 	case define.JSONLogging:
 		fallthrough
 	//lint:ignore ST1015 the default case has to be here

libpod/options.go

@@ -1114,7 +1114,7 @@ func WithLogDriver(driver string) CtrCreateOption {
 		switch driver {
 		case "":
 			return errors.Wrapf(define.ErrInvalidArg, "log driver must be set")
-		case define.JournaldLogging, define.KubernetesLogging, define.JSONLogging, define.NoLogging:
+		case define.JournaldLogging, define.KubernetesLogging, define.JSONLogging, define.NoLogging, define.PassthroughLogging:
 			break
 		default:
 			return errors.Wrapf(define.ErrInvalidArg, "invalid log driver")

libpod/runtime_ctr.go

@@ -474,7 +474,7 @@ func (r *Runtime) setupContainer(ctx context.Context, ctr *Container) (_ *Contai
 	}
 
 	switch ctr.config.LogDriver {
-	case define.NoLogging:
+	case define.NoLogging, define.PassthroughLogging:
 		break
 	case define.JournaldLogging:
 		ctr.initializeJournal(ctx)