feat: implement app-json-is-valid plugin trigger

docs/development/plugin-triggers.md

@@ -119,6 +119,21 @@ set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
 # TODO
 ```
 
+### `app-json-is-valid`
+
+- Description: Checks to see if the provided app.json file is valid
+- Invoked by: Appjson extraction during deployment
+- Arguments: `$APP $APP_JSON_PATH`
+- Example:
+
+```shell
+#!/usr/bin/env bash
+
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+
+# TODO
+```
+
 ### `app-maybe-create`
 
 - Description: Creates an app (gated by whether this is globally enabled or not)

plugins/app-json/appjson.go

@@ -200,21 +200,9 @@ func GetAppJSON(appName string) (AppJSON, error) {
 		return AppJSON{}, nil
 	}
 
-	b, err := os.ReadFile(getProcessSpecificAppJSONPath(appName))
-	if err != nil {
-		return AppJSON{}, fmt.Errorf("Cannot read app.json file: %v", err)
-	}
+	appJSONPath := getProcessSpecificAppJSONPath(appName)
 
-	if strings.TrimSpace(string(b)) == "" {
-		return AppJSON{}, nil
-	}
-
-	var appJSON AppJSON
-	if err = json.Unmarshal(b, &appJSON); err != nil {
-		return AppJSON{}, fmt.Errorf("Cannot parse app.json: %v", err)
-	}
-
-	return appJSON, nil
+	return ReadAppJSON(appJSONPath)
 }
 
 func GetAutoscalingConfig(appName string, processType string, replicas int) (FormationAutoscaling, bool, error) {
@@ -256,3 +244,22 @@ func GetAutoscalingConfig(appName string, processType string, replicas int) (For
 
 	return autoscaling, true, nil
 }
+
+// ReadAppJSON reads an app.json file from a given path
+func ReadAppJSON(path string) (AppJSON, error) {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return AppJSON{}, fmt.Errorf("Cannot read app.json file: %v", err)
+	}
+
+	if strings.TrimSpace(string(b)) == "" {
+		return AppJSON{}, nil
+	}
+
+	var appJSON AppJSON
+	if err = json.Unmarshal(b, &appJSON); err != nil {
+		return AppJSON{}, fmt.Errorf("Cannot parse app.json: %v", err)
+	}
+
+	return appJSON, nil
+}

plugins/app-json/triggers.go

@@ -1,7 +1,7 @@
 package appjson
 
 import (
-	"encoding/json"
+	"errors"
 	"fmt"
 	"os"
 	"path"
@@ -142,31 +142,16 @@ func TriggerCorePostExtract(appName string, sourceWorkDir string) error {
 	}
 
 	if hasAppJSON(appName) {
-		b, err := os.ReadFile(processSpecificAppJSON)
+		result, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
+			Trigger: "app-json-is-valid",
+			Args:    []string{appName, processSpecificAppJSON},
+		})
 		if err != nil {
-			return err
-		}
-
-		content := strings.TrimSpace(string(b))
-		if content == "" {
-			return nil
-		}
-
-		var appJSON AppJSON
-		if err := json.Unmarshal([]byte(content), &appJSON); err != nil {
-			return fmt.Errorf("Unable to unmarshal app.json: %v", err.Error())
-		}
-
-		if appJSON.Cron != nil {
-			for i, c := range appJSON.Cron {
-				if c.Command == "" {
-					return fmt.Errorf("Missing cron command for app %s (index %d)", appName, i)
-				}
-
-				if c.Schedule == "" {
-					return fmt.Errorf("Missing cron schedule for app %s (index %d)", appName, i)
-				}
+			if result.StderrContents() != "" {
+				return errors.New(result.StderrContents())
 			}
+
+			return err
 		}
 	}
 

plugins/cron/cron.go

@@ -62,21 +62,32 @@ func (t TemplateCommand) CronCommand() string {
 	return fmt.Sprintf("dokku run --cron-id %s %s %s", t.ID, t.App, t.Command)
 }
 
+// FetchCronEntriesInput is the input for the FetchCronEntries function
+type FetchCronEntriesInput struct {
+	AppName string
+	AppJSON *appjson.AppJSON
+}
+
 // FetchCronEntries returns a list of cron commands for a given app
-func FetchCronEntries(appName string) ([]TemplateCommand, error) {
+func FetchCronEntries(input FetchCronEntriesInput) ([]TemplateCommand, error) {
+	appName := input.AppName
 	commands := []TemplateCommand{}
 	isMaintenance := reportComputedMaintenance(appName) == "true"
 
-	appJSON, err := appjson.GetAppJSON(appName)
-	if err != nil {
-		return commands, fmt.Errorf("Unable to fetch app.json for app %s: %s", appName, err.Error())
+	if input.AppJSON == nil {
+		appJSON, err := appjson.GetAppJSON(appName)
+		if err != nil {
+			return commands, fmt.Errorf("Unable to fetch app.json for app %s: %s", appName, err.Error())
+		}
+
+		input.AppJSON = &appJSON
 	}
 
-	if appJSON.Cron == nil {
+	if input.AppJSON.Cron == nil {
 		return commands, nil
 	}
 
-	for i, c := range appJSON.Cron {
+	for i, c := range input.AppJSON.Cron {
 		if c.Command == "" {
 			common.LogWarn(fmt.Sprintf("Missing cron command for app %s (index %d)", appName, i))
 			continue

plugins/cron/report.go

@@ -41,7 +41,7 @@ func reportMailto(_ string) string {
 }
 
 func reportTasks(appName string) string {
-	c, _ := FetchCronEntries(appName)
+	c, _ := FetchCronEntries(FetchCronEntriesInput{AppName: appName})
 	return strconv.Itoa(len(c))
 }
 

plugins/cron/subcommands.go

@@ -26,7 +26,7 @@ func CommandList(appName string, format string) error {
 		return fmt.Errorf("Invalid format specified, supported formats: json, stdout")
 	}
 
-	entries, err := FetchCronEntries(appName)
+	entries, err := FetchCronEntries(FetchCronEntriesInput{AppName: appName})
 	if err != nil {
 		return err
 	}
@@ -79,7 +79,7 @@ func CommandRun(appName string, cronID string, detached bool) error {
 		return err
 	}
 
-	entries, err := FetchCronEntries(appName)
+	entries, err := FetchCronEntries(FetchCronEntriesInput{AppName: appName})
 	if err != nil {
 		return err
 	}

plugins/cron/triggers.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 
+	appjson "github.com/dokku/dokku/plugins/app-json"
 	"github.com/dokku/dokku/plugins/common"
 )
 
@@ -23,6 +24,25 @@ func TriggerCronGetProperty(appName string, key string) error {
 	return nil
 }
 
+// TriggerAppJSONIsValid validates the cron entries for a given app
+func TriggerAppJSONIsValid(appName string, appJSONPath string) error {
+	if !common.FileExists(appJSONPath) {
+		return nil
+	}
+
+	appJSON, err := appjson.ReadAppJSON(appJSONPath)
+	if err != nil {
+		return err
+	}
+
+	_, err = FetchCronEntries(FetchCronEntriesInput{AppName: appName, AppJSON: &appJSON})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // TriggerInstall runs the install step for the cron plugin
 func TriggerInstall() error {
 	if err := common.PropertySetup("cron"); err != nil {

plugins/scheduler-docker-local/functions.go

@@ -52,7 +52,7 @@ func generateCronEntries() ([]cron.TemplateCommand, error) {
 				return nil
 			}
 
-			c, err := cron.FetchCronEntries(appName)
+			c, err := cron.FetchCronEntries(cron.FetchCronEntriesInput{AppName: appName})
 			if err != nil {
 				results <- []cron.TemplateCommand{}
 				common.LogWarn(err.Error())

plugins/scheduler-k3s/triggers.go

@@ -266,7 +266,7 @@ func TriggerSchedulerDeploy(scheduler string, appName string, imageTag string) e
 
 	workingDir := common.GetWorkingDir(appName, image)
 
-	allCronEntries, err := cron.FetchCronEntries(appName)
+	allCronEntries, err := cron.FetchCronEntries(cron.FetchCronEntriesInput{AppName: appName})
 	if err != nil {
 		return fmt.Errorf("Error fetching cron entries: %w", err)
 	}