podman events format json

Enable podman events to format the output as jsonline

Signed-off-by: Qi Wang <qiwan@redhat.com>

docs/podman-events.1.md

@@ -68,7 +68,7 @@ Print usage statement.
 
 **--format**
 
-Format the output using the given Go template.  An output value of *json* is not supported.
+Format the output to JSON Lines or using the given Go template.
 
 
 **--filter**=*filter*
@@ -134,6 +134,13 @@ $ sudo podman events --since 5m
 2019-03-02 10:44:42.374637304 -0600 CST pod create ca731231718e (image=, name=webapp)
 ```
 
+Show podman events in JSON Lines format
+```
+events --format json
+{"ID":"683b0909d556a9c02fa8cd2b61c3531a965db42158627622d1a67b391964d519","Image":"localhost/myshdemo:latest","Name":"agitated_diffie","Status":"cleanup","Time":"2019-04-27T22:47:00.849932843-04:00","Type":"container"}
+{"ID":"a0f8ab051bfd43f9c5141a8a2502139707e4b38d98ac0872e57c5315381e88ad","Image":"docker.io/library/alpine:latest","Name":"friendly_tereshkova","Status":"unmount","Time":"2019-04-28T13:43:38.063017276-04:00","Type":"container"}
+```
+
 ## SEE ALSO
 podman(1)
 

libpod/events/config.go

@@ -22,13 +22,13 @@ const (
 type Event struct {
 	// ContainerExitCode is for storing the exit code of a container which can
 	// be used for "internal" event notification
-	ContainerExitCode int
+	ContainerExitCode int `json:",omitempty"`
 	// ID can be for the container, image, volume, etc
-	ID string
+	ID string `json:",omitempty"`
 	// Image used where applicable
-	Image string
+	Image string `json:",omitempty"`
 	// Name where applicable
-	Name string
+	Name string `json:",omitempty"`
 	// Status describes the event that occurred
 	Status Status
 	// Time the event occurred

pkg/adapter/runtime.go

@@ -5,22 +5,22 @@ package adapter
 import (
 	"bufio"
 	"context"
-	"github.com/containers/libpod/libpod/define"
 	"io"
 	"io/ioutil"
 	"os"
 	"text/template"
 
-	"github.com/containers/libpod/cmd/podman/shared"
-
 	"github.com/containers/buildah"
 	"github.com/containers/buildah/imagebuildah"
+	"github.com/containers/buildah/pkg/formats"
 	"github.com/containers/buildah/pkg/parse"
 	"github.com/containers/image/docker/reference"
 	"github.com/containers/image/types"
 	"github.com/containers/libpod/cmd/podman/cliconfig"
 	"github.com/containers/libpod/cmd/podman/libpodruntime"
+	"github.com/containers/libpod/cmd/podman/shared"
 	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/libpod/define"
 	"github.com/containers/libpod/libpod/events"
 	"github.com/containers/libpod/libpod/image"
 	"github.com/containers/libpod/pkg/rootless"
@@ -351,9 +351,13 @@ func (r *LocalRuntime) Events(c *cliconfig.EventValues) error {
 		fromStart   bool
 		eventsError error
 	)
-	tmpl, err := template.New("events").Parse(c.Format)
-	if err != nil {
-		return err
+	var tmpl *template.Template
+	if c.Format != formats.JSONString {
+		template, err := template.New("events").Parse(c.Format)
+		if err != nil {
+			return err
+		}
+		tmpl = template
 	}
 	if len(c.Since) > 0 || len(c.Until) > 0 {
 		fromStart = true
@@ -369,7 +373,15 @@ func (r *LocalRuntime) Events(c *cliconfig.EventValues) error {
 	}
 	w := bufio.NewWriter(os.Stdout)
 	for event := range eventChannel {
-		if len(c.Format) > 0 {
+		if c.Format == formats.JSONString {
+			jsonStr, err := event.ToJSONString()
+			if err != nil {
+				return errors.Wrapf(err, "unable to format json")
+			}
+			if _, err := w.Write([]byte(jsonStr)); err != nil {
+				return err
+			}
+		} else if len(c.Format) > 0 {
 			if err := tmpl.Execute(w, event); err != nil {
 				return err
 			}

pkg/adapter/runtime_remote.go

@@ -14,9 +14,8 @@ import (
 	"text/template"
 	"time"
 
-	v1 "k8s.io/api/core/v1"
-
 	"github.com/containers/buildah/imagebuildah"
+	"github.com/containers/buildah/pkg/formats"
 	"github.com/containers/image/docker/reference"
 	"github.com/containers/image/types"
 	"github.com/containers/libpod/cmd/podman/cliconfig"
@@ -32,6 +31,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"github.com/varlink/go/varlink"
+	v1 "k8s.io/api/core/v1"
 )
 
 // ImageRuntime is wrapper for image runtime
@@ -820,9 +820,13 @@ func (r *LocalRuntime) Events(c *cliconfig.EventValues) error {
 	}
 
 	w := bufio.NewWriter(os.Stdout)
-	tmpl, err := template.New("events").Parse(c.Format)
-	if err != nil {
-		return err
+	var tmpl *template.Template
+	if c.Format != formats.JSONString {
+		template, err := template.New("events").Parse(c.Format)
+		if err != nil {
+			return err
+		}
+		tmpl = template
 	}
 
 	for {
@@ -856,7 +860,15 @@ func (r *LocalRuntime) Events(c *cliconfig.EventValues) error {
 			Time:   eTime,
 			Type:   eType,
 		}
-		if len(c.Format) > 0 {
+		if c.Format == formats.JSONString {
+			jsonStr, err := event.ToJSONString()
+			if err != nil {
+				return errors.Wrapf(err, "unable to format json")
+			}
+			if _, err := w.Write([]byte(jsonStr)); err != nil {
+				return err
+			}
+		} else if len(c.Format) > 0 {
 			if err := tmpl.Execute(w, event); err != nil {
 				return err
 			}

test/e2e/events_test.go

@@ -1,6 +1,7 @@
 package integration
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 	"strings"
@@ -116,4 +117,25 @@ var _ = Describe("Podman events", func() {
 		Expect(result.ExitCode()).To(BeZero())
 	})
 
+	It("podman events format", func() {
+		info := GetHostDistributionInfo()
+		if info.Distribution != "fedora" {
+			Skip("need to verify images have correct packages for journald")
+		}
+		_, ec, _ := podmanTest.RunLsContainer("")
+		Expect(ec).To(Equal(0))
+		test := podmanTest.Podman([]string{"events", "--stream=false", "--format", "json"})
+		test.WaitWithDefaultTimeout()
+		fmt.Println(test.OutputToStringArray())
+		jsonArr := test.OutputToStringArray()
+		Expect(len(jsonArr)).To(Not(BeZero()))
+		eventsMap := make(map[string]string)
+		err := json.Unmarshal([]byte(jsonArr[0]), &eventsMap)
+		if err != nil {
+			os.Exit(1)
+		}
+		_, exist := eventsMap["Status"]
+		Expect(exist).To(BeTrue())
+		Expect(test.ExitCode()).To(BeZero())
+	})
 })