feat: add a new plugin trigger for detecting what the current deployment method is

This is currently used solely for reporting.

Closes #3047

plugins/20_events/bind-external-ip

@@ -1,5 +0,0 @@
-#!/usr/bin/env bash
-set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
-source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
-
-[[ ! "$DOKKU_EVENTS" ]] || dokku_log_plugn_trigger_call "$(basename "$0")" "$@"

plugins/20_events/deploy-method

@@ -0,0 +1 @@
+hook

plugins/apps/subcommands/report

@@ -15,6 +15,7 @@ report_single_app() {
   local flag_map=(
     "--app-dir: $APP_DIR"
     "--git-sha: $(GIT_DIR="$APP_DIR" git rev-parse --short HEAD 2> /dev/null || false)"
+    "--deploy-method: $(plugn trigger deploy-method "$APP")"
   )
 
   if [[ -z "$INFO_FLAG" ]]; then

plugins/git/deploy-method

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+
+git_deploy_method() {
+  declare desc="git deploy-method plugin trigger"
+  declare trigger="git_deploy_method"
+  declare APP="$1"
+  local STDIN=$(cat)
+
+  # bail if another method is detected
+  if [[ -n "$STDIN" ]]; then
+  	echo "$STDIN"
+  	return
+  fi
+
+  if [[ -d "$DOKKU_ROOT/$APP/refs" ]]; then
+    echo "git"
+  fi
+}
+
+git_deploy_method "$@"

plugins/tar/deploy-method

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+
+tar_deploy_method() {
+  declare desc="tar deploy-method plugin trigger"
+  declare trigger="tar_deploy_method"
+  declare APP="$1"
+  local STDIN=$(cat)
+
+  # bail if another method is detected
+  if [[ -n "$STDIN" ]]; then
+  	echo "$STDIN"
+  	return
+  fi
+
+  if [[ -f "$DOKKU_ROOT/$APP/src.tar" ]]; then
+    echo "tar"
+  fi
+}
+
+tar_deploy_method "$@"