json output for exec command

cmd/exec.go

@@ -6,31 +6,45 @@ package cmd
 
 import (
 	"context"
+	"encoding/json"
+	"errors"
 	"fmt"
 	"strings"
 
+	"github.com/google/shlex"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 	"github.com/srl-labs/containerlab/clab"
 	"github.com/srl-labs/containerlab/types"
 )
 
-var labels []string
+var (
+	labels      []string
+	execFormat  string
+	execCommand string
+)
 
 // execCmd represents the exec command
 var execCmd = &cobra.Command{
 	Use:     "exec",
 	Short:   "execute a command on one or multiple containers",
 	PreRunE: sudoCheck,
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		if name == "" && topo == "" {
-			fmt.Println("provide either lab name (--name) or topology file path (--topo)")
-			return
+			return errors.New("provide either lab name (--name) or topology file path (--topo)")
+
+		}
+
+		if execCommand == "" {
+			return errors.New("provide command to execute")
 		}
-		log.Debugf("raw command: %v", args)
-		if len(args) == 0 {
-			fmt.Println("provide command to execute")
-			return
+
+		switch execFormat {
+		case "json",
+			"plain":
+			// expected values, go on
+		default:
+			log.Error("format is expected to be either json or plain")
 		}
 		opts := []clab.ClabOption{
 			clab.WithDebug(debug),
@@ -52,14 +66,18 @@ var execCmd = &cobra.Command{
 			log.Fatalf("could not list containers: %v", err)
 		}
 		if len(containers) == 0 {
-			log.Println("no containers found")
-			return
+			return errors.New("no containers found")
 		}
-		cmds := make([]string, 0, len(args))
-		for _, a := range args {
-			cmds = append(cmds, strings.Split(a, " ")...)
+
+		cmds, err := shlex.Split(execCommand)
+		if err != nil {
+			return err
 		}
+
+		jsonResult := make(map[string]map[string]interface{})
+
 		for _, cont := range containers {
+			var doc interface{}
 			if cont.State != "running" {
 				continue
 			}
@@ -68,17 +86,41 @@ var execCmd = &cobra.Command{
 				log.Errorf("%s: failed to execute cmd: %v", cont.Names, err)
 				continue
 			}
-			if len(stdout) > 0 {
-				log.Infof("%s: stdout:\n%s", cont.Names, string(stdout))
+			contName := strings.TrimLeft(cont.Names[0], "/")
+			switch execFormat {
+			case "json":
+				jsonResult[contName] = make(map[string]interface{})
+				err := json.Unmarshal([]byte(stdout), &doc)
+				if err == nil {
+					jsonResult[contName]["stdout"] = doc
+				} else {
+					jsonResult[contName]["stdout"] = string(stdout)
+				}
+				jsonResult[contName]["stderr"] = string(stderr)
+			case "plain":
+				if len(stdout) > 0 {
+					log.Infof("%s: stdout:\n%s", contName, string(stdout))
+				}
+				if len(stderr) > 0 {
+					log.Infof("%s: stderr:\n%s", contName, string(stderr))
+				}
+
 			}
-			if len(stderr) > 0 {
-				log.Infof("%s: stderr:\n%s", cont.Names, string(stderr))
+		}
+		if execFormat == "json" {
+			result, err := json.Marshal(jsonResult)
+			if err != nil {
+				log.Errorf("Issue converting to json %v", err)
 			}
+			fmt.Println(string(result))
 		}
+		return err
 	},
 }
 
 func init() {
 	rootCmd.AddCommand(execCmd)
+	execCmd.Flags().StringVarP(&execCommand, "cmd", "", "", "command to execute")
 	execCmd.Flags().StringSliceVarP(&labels, "label", "", []string{}, "labels to filter container subset")
+	execCmd.Flags().StringVarP(&execFormat, "format", "f", "plain", "output format. One of [json, plain]")
 }

docs/cmd/exec.md

@@ -0,0 +1,118 @@
+# exec command
+
+### Description
+
+The `exec` command allows to run a command inside the nodes that part of a certain lab.
+
+This command does exactly the same thing as `docker exec` does, but it allows to run the same command across all the nodes of a lab.
+
+### Usage
+
+`containerlab [global-flags] exec [local-flags]`
+
+### Flags
+
+#### topology
+
+With the global `--topo | -t` flag a user specifies from which lab to take the containers and perform the exec command.
+
+#### cmd
+The command to be executed on the nodes is provided with `--cmd` flag. The command is provided as a string, thus it needs to be quoted to accommodate for spaces or special characters.
+
+#### format
+The `--format | -f` flag allows to select between plain text format output or a json variant. Consult with the examples below to see the differences between these two formatting options.
+
+Defaults to `plain` output format.
+
+#### label
+By default `exec` command will attempt to execute the command across all the nodes of a lab. To limit the scope of the execution, the users can leverage the `--label` flag to filter out the nodes of interest.
+
+### Examples
+
+```bash
+# show ipv4 information from all the nodes of the lab
+# with a plain text output
+❯ containerlab exec -t srl02.yml --cmd 'ip -4 a show dummy-mgmt0'
+INFO[0000] clab-srl02-srl1: stdout:
+6: dummy-mgmt0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
+    inet 172.20.20.3/24 brd 172.20.20.255 scope global dummy-mgmt0
+       valid_lft forever preferred_lft forever
+INFO[0000] clab-srl02-srl2: stdout:
+6: dummy-mgmt0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
+    inet 172.20.20.2/24 brd 172.20.20.255 scope global dummy-mgmt0
+       valid_lft forever preferred_lft forever
+
+
+# execute a CLI command with a plain text output
+❯ containerlab exec -t srl02.yml --cmd 'sr_cli  "show version"'
+INFO[0001] clab-srl02-srl1: stdout:
+----------------------------------------------------
+Hostname          : srl1
+Chassis Type      : 7250 IXR-6
+Part Number       : Sim Part No.
+Serial Number     : Sim Serial No.
+System MAC Address: 02:00:6B:FF:00:00
+Software Version  : v20.6.3
+Build Number      : 145-g93496a3f8c
+Architecture      : x86_64
+Last Booted       : 2021-06-24T10:25:26.722Z
+Total Memory      : 24052875 kB
+Free Memory       : 21911906 kB
+----------------------------------------------------
+INFO[0003] clab-srl02-srl2: stdout:
+----------------------------------------------------
+Hostname          : srl2
+Chassis Type      : 7250 IXR-6
+Part Number       : Sim Part No.
+Serial Number     : Sim Serial No.
+System MAC Address: 02:D8:A9:FF:00:00
+Software Version  : v20.6.3
+Build Number      : 145-g93496a3f8c
+Architecture      : x86_64
+Last Booted       : 2021-06-24T10:25:26.904Z
+Total Memory      : 24052875 kB
+Free Memory       : 21911914 kB
+----------------------------------------------------
+
+
+# execute a CLI command with a json output
+❯ containerlab exec -t srl02.yml --cmd 'sr_cli  "show version | as json"' -f json | jq
+{
+  "clab-srl02-srl1": {
+    "stderr": "",
+    "stdout": {
+      "basic system info": {
+        "Architecture": "x86_64",
+        "Build Number": "145-g93496a3f8c",
+        "Chassis Type": "7250 IXR-6",
+        "Free Memory": "21911367 kB",
+        "Hostname": "srl1",
+        "Last Booted": "2021-06-24T10:25:26.722Z",
+        "Part Number": "Sim Part No.",
+        "Serial Number": "Sim Serial No.",
+        "Software Version": "v20.6.3",
+        "System MAC Address": "02:00:6B:FF:00:00",
+        "Total Memory": "24052875 kB"
+      }
+    }
+  },
+  "clab-srl02-srl2": {
+    "stderr": "",
+    "stdout": {
+      "basic system info": {
+        "Architecture": "x86_64",
+        "Build Number": "145-g93496a3f8c",
+        "Chassis Type": "7250 IXR-6",
+        "Free Memory": "21911367 kB",
+        "Hostname": "srl2",
+        "Last Booted": "2021-06-24T10:25:26.904Z",
+        "Part Number": "Sim Part No.",
+        "Serial Number": "Sim Serial No.",
+        "Software Version": "v20.6.3",
+        "System MAC Address": "02:D8:A9:FF:00:00",
+        "Total Memory": "24052875 kB"
+      }
+    }
+  }
+}
+```

mkdocs.yml

@@ -35,6 +35,7 @@ nav:
       - destroy: cmd/destroy.md
       - inspect: cmd/inspect.md
       - save: cmd/save.md
+      - exec: cmd/exec.md
       - generate: cmd/generate.md
       - graph: cmd/graph.md
       - tools:

tests/01-smoke/03-bridges-and-host.robot

@@ -55,7 +55,7 @@ Verify management network is using user-specified bridge
     # show management interface info and cut the information about the ifindex of the remote veth
     # note that exec returns the info in the stderr stream, thus we use stderr to parse the ifindex
     ${rc}    ${iface} =    OperatingSystem.Run And Return Rc And Output
-    ...    sudo containerlab --runtime ${runtime} exec -t ${CURDIR}/${lab-file} --label clab-node-name\=l1 ip l show eth0 2>&1 | cut -d ' ' -f5 | cut -d '@' -f2 | cut -c3-
+    ...    sudo containerlab --runtime ${runtime} exec -t ${CURDIR}/${lab-file} --label clab-node-name\=l1 --cmd "ip l show eth0" 2>&1 | cut -d ' ' -f5 | cut -d '@' -f2 | cut -c3-
     Log    ${iface}
     Should Be Equal As Integers    ${rc}    0
     ${rc}    ${res} =    OperatingSystem.Run And Return Rc And Output