feat: implement proxy container :label functionality

plugins/proxy/functions

@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
+
+fn-proxy-escape-extended-sed() {
+  # Escaped delimiter is '/'
+  local input="$1"
+  echo "$input" | sed -E 's#[][()\.^$?*+{}|/]#\\&#g'
+}
+
+fn-proxy-report-label-overwrite() {
+  declare desc="overwrite proxy labels file with new labels"
+  declare LABELS="$1" PROXY_LABELS_FILE_PATH="$2"
+
+  if [[ -f "$PROXY_LABELS_FILE_PATH" ]]; then
+    local DONE=false
+    until $DONE; do
+      local line
+      read -r line || local DONE=true
+
+      [[ -z "$line" ]] && continue
+
+      case "$line" in
+        \#*)
+          continue
+          ;;
+
+        --label*)
+          local label_name="$(echo "$line" | sed -E "s/^--label ['\"]([^=]+)=.*/\1/")"
+          local escaped_label_name="$(fn-proxy-escape-extended-sed "$passed_label_name")"
+          local match="$(echo "$LABELS" | sed -E "s/.*--label ['\"]($escaped_label_name)=.*/\1/")"
+          if [[ -n "$match" ]]; then
+            dokku_log_warn "Dokku label \"$match\" will be overwritten by user-set proxy label."
+          fi
+          continue
+          ;;
+
+        *)
+          dokku_log_warn "Invalid line '$line' in proxy label file $PROXY_FILE_PATH"
+          ;;
+      esac
+    done <"$PROXY_LABELS_FILE_PATH"
+  fi
+}
+
+fn-proxy-get-labels-file-path() {
+  declare desc="return proxy labels config file path for specified proxy"
+  declare PROXY="$1" APP="$2"
+  local PROXY_FILE="${DOKKU_ROOT}/${APP}/PROXY_LABELS_${PROXY^^}"
+
+  echo "$PROXY_FILE"
+}
+
+fn-proxy-display-labels() {
+  declare desc="print user-set app container labels for specified proxy"
+  declare PROXY="$1" APP="$2"
+  local proxy_labels_file_path="$(fn-proxy-get-labels-file-path "$PROXY" "$APP")"
+  echo "${PROXY^} labels:"
+  sed -e 's/^/    /' "$proxy_labels_file_path"
+}
+
+fn-proxy-show-label() {
+  declare desc="print single user-set app container label for specified proxy"
+  declare PROXY="$1" APP="$2" PASSED_LABEL_NAME="$3"
+
+  local proxy_labels_file_path="$(fn-proxy-get-labels-file-path "$PROXY" "$APP")"
+  if [[ ! -s "$proxy_labels_file_path" ]]; then
+    return
+  fi
+
+  local all_proxy_labels="$(<"$proxy_labels_file_path")"
+  local escaped_label_name="$(fn-proxy-escape-extended-sed "$passed_label_name")"
+  local proxy_label_value="$(echo -e "${all_proxy_labels}" | sed -E -n "s/^--label ['\"]${escaped_label_name}=(.*)['\"] \$/\1/p")"
+
+  echo "$proxy_label_value"
+}