[feature] add --env to dokku run

`dokku run [ --env KEY=VALUE | -e KEY=VALUE ] app command`

__note__ this changes the scheduler-run trigger to expect the following arguments:
scheduler_name, app_name, env_count, env_0, ..., env_n, app_arg_0, ..., app_arg_n

resolves: dokku/dokku#3291

plugins/00_dokku-standard/commands

@@ -9,7 +9,7 @@ case "$1" in
     help_content_func() {
       declare desc="return standard plugin help content"
       cat <<help_content
-    run <app> <cmd>, Run a command in a new container using the current application image
+    run [--env KEY=VALUE] <app> <cmd>, Run a command in a new container using the current application image
     trace [on/off], Enable dokku tracing
     url <app>, Show the first URL for an application (compatibility)
     urls <app>, Show all URLs for an application

plugins/00_dokku-standard/subcommands/run

@@ -6,12 +6,38 @@ source "$PLUGIN_AVAILABLE_PATH/config/functions"
 
 dokku_run_cmd() {
   declare desc="runs command in container based on app image"
-  declare cmd="run" APP="$2"
+  declare cmd="run" APP=""
+  shift
+
+  declare -a RUN_ENV
+  RUN_ENV=()
+  while [[ $# -gt 0 ]]; do
+    case $1 in
+      -e=* | --env=*)
+        local arg=$(printf "%s" "$1" | sed -E 's/(^-e=)|(^--env=)//g')
+        RUN_ENV+=("$arg")
+        shift
+        ;;
+      -e | --env)
+        if [[ ! $2 ]]; then
+          dokku_log_warn "expected $1 to have an argument"
+          break
+        fi
+        RUN_ENV+=("$2")
+        shift 2
+        ;;
+      *)
+        APP="$1"
+        shift
+        break
+        ;;
+    esac
+  done
+
   verify_app_name "$APP"
-  shift 2
 
   local DOKKU_SCHEDULER=$(get_app_scheduler "$APP")
-  plugn trigger scheduler-run "$DOKKU_SCHEDULER" "$APP" "$@"
+  plugn trigger scheduler-run "$DOKKU_SCHEDULER" "$APP" "${#RUN_ENV[@]}" "${RUN_ENV[@]}" "$@"
 }
 
 dokku_run_cmd "$@"

plugins/scheduler-docker-local/scheduler-run

@@ -8,8 +8,11 @@ source "$PLUGIN_AVAILABLE_PATH/ps/functions"
 scheduler-docker-local-scheduler-run() {
   declare desc="runs command in container based on app image"
   declare trigger="scheduler-docker-local scheduler-run"
-  declare DOKKU_SCHEDULER="$1" APP="$2"
-  shift 2
+  declare DOKKU_SCHEDULER="$1" APP="$2" ENV_COUNT="$3"
+  shift 3
+
+  declare RUN_ENV=("${@:1:ENV_COUNT}")
+  shift "$ENV_COUNT"
 
   if [[ "$DOKKU_SCHEDULER" != "docker-local" ]]; then
     return
@@ -25,23 +28,25 @@ scheduler-docker-local-scheduler-run() {
   fi
 
   local DOCKER_ARGS=$(: | plugn trigger docker-args-run "$APP" "$IMAGE_TAG")
-  [[ "$DOKKU_TRACE" ]] && local DOCKER_ARGS+=" -e TRACE=true "
+  [[ "$DOKKU_TRACE" ]] && DOCKER_ARGS+=" -e TRACE=true "
 
   local IMAGE_SOURCE_TYPE="dockerfile"
   is_image_herokuish_based "$IMAGE" && IMAGE_SOURCE_TYPE="herokuish"
   DOCKER_ARGS+=$(: | plugn trigger docker-args-process-run "$APP" "$IMAGE_TAG" "$IMAGE_SOURCE_TYPE" "$PHASE_SCRIPT_KEY")
-
-  declare -a ARG_ARRAY
-  eval "ARG_ARRAY=($DOCKER_ARGS)"
-
-  local DOKKU_RUN_OPTS=" -e DYNO=run.$RANDOM"
+  DOCKER_ARGS+=" -e DYNO=run.$RANDOM"
   if [[ "$DOKKU_RM_CONTAINER" ]]; then
-    DOKKU_RUN_OPTS+=" --rm"
+    DOCKER_ARGS+=" --rm"
   elif [[ "$DOKKU_DETACH_CONTAINER" ]]; then
-    DOKKU_RUN_OPTS+=" --detach"
+    DOCKER_ARGS+=" --detach"
   fi
+  has_tty && DOCKER_ARGS+=" -i -t"
+  # the output of docker-args-run is possibly quoted/escaped so eval to normalize
+  declare -a DOCKER_ARGS_ARRAY
+  eval "DOCKER_ARGS_ARRAY=($DOCKER_ARGS)"
+  for env_pair in "${RUN_ENV[@]}"; do
+    DOCKER_ARGS_ARRAY+=("--env=$env_pair")
+  done
 
-  has_tty && DOKKU_RUN_OPTS+=" -i -t"
   [[ "$IMAGE_SOURCE_TYPE" == "herokuish" ]] && local EXEC_CMD="/exec"
 
   DOKKU_QUIET_OUTPUT=1 extract_procfile "$APP"
@@ -56,7 +61,7 @@ scheduler-docker-local-scheduler-run() {
   fi
 
   # shellcheck disable=SC2086
-  docker run $DOKKU_GLOBAL_RUN_ARGS $DOKKU_RUN_OPTS "${ARG_ARRAY[@]}" $IMAGE $EXEC_CMD "$@"
+  docker run $DOKKU_GLOBAL_RUN_ARGS "${DOCKER_ARGS_ARRAY[@]}" $IMAGE $EXEC_CMD "$@"
 }
 
 scheduler-docker-local-scheduler-run "$@"