feat: add json format output to cron:list command

This makes it easier to parse output in a machine-readable format - such as when interacting with cron tasks via jq for writing tests.

docs/processes/scheduled-cron-tasks.md

@@ -3,8 +3,8 @@
 > New as of 0.23.0
 
 ```
-cron:list <app>               # List scheduled cron tasks for an app
-cron:report [<app>] [<flag>]  # Display report about an app
+cron:list <app> [--format json|stdout] # List scheduled cron tasks for an app
+cron:report [<app>] [<flag>]           # Display report about an app
 ```
 
 ## Usage
@@ -62,6 +62,16 @@ cGhwPT09cGhwIHRlc3QucGhwPT09QGRhaWx5  @daily     node index.js
 cGhwPT09dHJ1ZT09PSogKiAqICogKg==      * * * * *  true
 ```
 
+The output can also be displayed in json format:
+
+```shell
+dokku cron:list node-js-app --format json
+```
+
+```
+[{"id":"cGhwPT09cGhwIHRlc3QucGhwPT09QGRhaWx5","app":"node-js-app","command":"node index.js","schedule":"@daily"}]
+```
+
 #### Displaying reports
 
 You can get a report about the cron configuration for apps using the `cron:report` command:

plugins/cron/cron.go

@@ -14,12 +14,12 @@ import (
 )
 
 type TemplateCommand struct {
-	ID         string
-	App        string
-	Command    string
-	Schedule   string
-	AltCommand string
-	LogFile    string
+	ID         string `json:"id"`
+	App        string `json:"app"`
+	Command    string `json:"command"`
+	Schedule   string `json:"schedule"`
+	AltCommand string `json:"-"`
+	LogFile    string `json:"-"`
 }
 
 func (t TemplateCommand) CronCommand() string {

plugins/cron/src/commands/commands.go

@@ -18,7 +18,7 @@ Manage scheduled cron tasks
 Additional commands:`
 
 	helpContent = `
-    cron:list <app>, List scheduled cron tasks for an app
+    cron:list <app> [--format json|stdout], List scheduled cron tasks for an app
     cron:report [<app>] [<flag>], Display report about an app
 `
 )

plugins/cron/src/subcommands/subcommands.go

@@ -20,9 +20,10 @@ func main() {
 	switch subcommand {
 	case "list":
 		args := flag.NewFlagSet("cron:list", flag.ExitOnError)
+		format := args.String("format", "stdout", "format: [ stdout | json ]")
 		args.Parse(os.Args[2:])
 		appName := args.Arg(0)
-		err = cron.CommandList(appName)
+		err = cron.CommandList(appName, *format)
 	case "report":
 		args := flag.NewFlagSet("cron:report", flag.ExitOnError)
 		format := args.String("format", "stdout", "format: [ stdout | json ]")

plugins/cron/subcommands.go

@@ -1,6 +1,7 @@
 package cron
 
 import (
+	"encoding/json"
 	"fmt"
 
 	"github.com/dokku/dokku/plugins/common"
@@ -8,22 +9,40 @@ import (
 )
 
 // CommandList lists all scheduled cron tasks for a given app
-func CommandList(appName string) error {
+func CommandList(appName string, format string) error {
 	if err := common.VerifyAppName(appName); err != nil {
 		return err
 	}
 
+	if format == "" {
+		format = "stdout"
+	}
+
+	if format != "stdout" && format != "json" {
+		return fmt.Errorf("Invalid format specified, supported formats: json, stdout")
+	}
+
 	entries, err := FetchCronEntries(appName)
 	if err != nil {
 		return err
 	}
 
-	output := []string{"ID | Schedule | Command"}
-	for _, entry := range entries {
-		output = append(output, fmt.Sprintf("%s | %s | %s", entry.ID, entry.Schedule, entry.Command))
+	if format == "stdout" {
+		output := []string{"ID | Schedule | Command"}
+		for _, entry := range entries {
+			output = append(output, fmt.Sprintf("%s | %s | %s", entry.ID, entry.Schedule, entry.Command))
+		}
+
+		result := columnize.SimpleFormat(output)
+		fmt.Println(result)
+		return nil
 	}
-	result := columnize.SimpleFormat(output)
-	fmt.Println(result)
+
+	out, err := json.Marshal(entries)
+	if err != nil {
+		return err
+	}
+	common.Log(string(out))
 
 	return nil
 }

tests/unit/cron.bats

@@ -177,6 +177,26 @@ teardown() {
   assert_failure
 }
 
+@test "(cron) cron:list --format json" {
+  run deploy_app python dokku@dokku.me:$TEST_APP template_cron_file_valid
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku cron:list $TEST_APP --format json"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output_exists
+
+  cron_id="$(dokku cron:list $TEST_APP --format json | jq -r '.[0].id')"
+  run /bin/bash -c "echo $cron_id"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output_exists
+}
+
 template_cron_file_invalid() {
   local APP="$1"
   local APP_REPO_DIR="$2"