feat: add trigger for fetching logs properties

docs/deployment/logs.md

@@ -59,7 +59,7 @@ dokku logs:failed --all
 
 ### Docker Log Retention
 
-Docker log retention can be specified via the `logs:set` command by specifying a value for `max-size`. Log retention is set via injected docker options for all applications, but is also available via a trigger for alternative schedulers.
+Docker log retention can be specified via the `logs:set` command by specifying a value for `max-size`. Log retention is set via injected docker options for all applications, but is also available via the `logs-get-property` trigger for alternative schedulers.
 
 ```shell
 dokku logs:set node-js-app max-size 20m

docs/development/plugin-triggers.md

@@ -699,6 +699,22 @@ if [[ ! -f  "$DOKKU_ROOT/HOSTNAME" ]]; then
 fi
 ```
 
+### `logs-get-property`
+
+- Description: Fetches a given logs property value
+- Invoked by:
+- Arguments: `$APP` `$PROPERTY`
+- Example:
+
+```shell
+#!/usr/bin/env bash
+
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+APP="$1"; PROPERTY="$2"
+
+# TODO
+```
+
 ### `network-build-config`
 
 - Description: Rebuilds network configuration

plugins/logs/Makefile

@@ -1,5 +1,5 @@
 SUBCOMMANDS = subcommands/failed subcommands/report subcommands/set subcommands/vector-logs subcommands/vector-start subcommands/vector-stop
-TRIGGERS = triggers/docker-args-process-deploy triggers/install triggers/post-delete triggers/report
+TRIGGERS = triggers/docker-args-process-deploy triggers/install triggers/logs-get-property triggers/post-delete triggers/report
 BUILD = commands subcommands triggers
 PLUGIN_NAME = logs
 

plugins/logs/src/triggers/triggers.go

@@ -23,6 +23,10 @@ func main() {
 		err = logs.TriggerDockerArgsProcessDeploy(appName)
 	case "install":
 		err = logs.TriggerInstall()
+	case "logs-get-property":
+		appName := flag.Arg(0)
+		property := flag.Arg(1)
+		err = logs.TriggerLogsGetProperty(appName, property)
 	case "post-delete":
 		appName := flag.Arg(0)
 		err = logs.TriggerPostDelete(appName)

plugins/logs/triggers.go

@@ -1,6 +1,7 @@
 package logs
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -56,6 +57,21 @@ func TriggerInstall() error {
 	return nil
 }
 
+// TriggerLogsGetProperty writes the logs key to stdout for a given app container
+func TriggerLogsGetProperty(appName string, key string) error {
+	if key != "max-size" {
+		return errors.New("Invalid logs property specified")
+	}
+
+	value := common.PropertyGet("logs", appName, "max-size")
+	if value == "" {
+		value = common.PropertyGetDefault("logs", "--global", "max-size", MaxSize)
+	}
+
+	fmt.Println(value)
+	return nil
+}
+
 // TriggerPostDelete destroys the network property for a given app container
 func TriggerPostDelete(appName string) error {
 	return common.PropertyDestroy("logs", appName)