[config] improve logging and default command

plugins/config/config.go

@@ -0,0 +1,26 @@
+package config
+
+import configenv "github.com/dokku/dokku/plugins/config/src/configenv"
+import columnize "github.com/ryanuber/columnize"
+import "fmt"
+
+//GetWithDefault gets value from app config
+func GetWithDefault(appName string, key string, defaultValue string) string {
+	env, err := configenv.NewFromTarget(appName)
+	if err != nil {
+		return defaultValue
+	}
+	return env.GetDefault(key, defaultValue)
+}
+
+//PrettyPrintLogEntries in columns
+func PrettyPrintLogEntries(prefix string, entries map[string]string) string {
+	colConfig := columnize.DefaultConfig()
+	colConfig.Prefix = prefix
+	colConfig.Delim = "\x00"
+	lines := make([]string, 0, len(entries))
+	for k, v := range entries {
+		lines = append(lines, fmt.Sprintf("%s:\x00%s", k, v))
+	}
+	return columnize.Format(lines, colConfig)
+}