feat: add the ability to specify the output format when listing ports

docs/development/plugin-triggers.md

@@ -1371,7 +1371,7 @@ set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
 
 - Description: Returns a list of port mappings, newline delimited
 - Invoked by: Various networking plugins
-- Arguments: `$APP`
+- Arguments: `$APP $FORMAT`
 - Example:
 
 ```shell

plugins/ports/proxy.go

@@ -6,9 +6,9 @@ import (
 
 // PortMap is a struct that contains a scheme:host-port:container-port mapping
 type PortMap struct {
-	ContainerPort int
-	HostPort      int
-	Scheme        string
+	ContainerPort int    `json:"container_port"`
+	HostPort      int    `json:"host_port"`
+	Scheme        string `json:"scheme"`
 }
 
 func (p PortMap) String() string {

plugins/ports/src/triggers/triggers.go

@@ -28,7 +28,8 @@ func main() {
 		err = ports.TriggerPortsConfigure(appName)
 	case "ports-get":
 		appName := flag.Arg(0)
-		err = ports.TriggerPortsGet(appName)
+		format := flag.Arg(1)
+		err = ports.TriggerPortsGet(appName, format)
 	case "ports-get-available":
 		err = ports.TriggerPortsGetAvailable()
 	case "ports-get-property":

plugins/ports/triggers.go

@@ -1,6 +1,7 @@
 package ports
 
 import (
+	"encoding/json"
 	"fmt"
 	"sort"
 
@@ -64,17 +65,35 @@ func TriggerPortsConfigure(appName string) error {
 }
 
 // TriggerPortsGet prints out the port mapping for a given app
-func TriggerPortsGet(appName string) error {
+func TriggerPortsGet(appName string, format string) error {
+	if format != "json" && format != "stdout" {
+		return fmt.Errorf("Invalid format specified: %s", format)
+	}
 	portMaps := getPortMaps(appName)
 	if len(portMaps) == 0 {
 		portMaps = getDetectedPortMaps(appName)
 	}
 
+	persisted := []PortMap{}
 	for _, portMap := range portMaps {
 		if portMap.AllowsPersistence() {
 			continue
 		}
 
+		persisted = append(persisted, portMap)
+	}
+
+	if format == "json" {
+		b, err := json.Marshal(persisted)
+		if err != nil {
+			return fmt.Errorf("Unable to marshal port mapping: %s", err.Error())
+		}
+
+		fmt.Println(string(b))
+		return nil
+	}
+
+	for _, portMap := range persisted {
 		fmt.Println(portMap)
 	}