From 7aa48d34264d3aad95299b423a8eda7072edbeee Mon Sep 17 00:00:00 2001
From: Michael Hobbs <michaelshobbs@users.noreply.github.com>
Date: Wed, 11 May 2016 16:40:10 -0700
Subject: [PATCH] enter default container type if only a single type is running

---
 docs/deployment/one-off-processes.md |  2 ++
 plugins/common/functions             |  2 +-
 plugins/enter/subcommands/default    | 37 +++++++++++++++++++++-------
 3 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/docs/deployment/one-off-processes.md b/docs/deployment/one-off-processes.md
index befe4a028..804e250c6 100644
--- a/docs/deployment/one-off-processes.md
+++ b/docs/deployment/one-off-processes.md
@@ -68,6 +68,8 @@ dokku enter node-js-app web.1
 dokku enter node-js-app --container-id ID
 ```
 
+Additionally, you can run `enter` with no container-type. If only a single container-type is defined in your app, you will be dropped into the only running container. This behavior is not supported when specifying a custom command; as described below.
+
 By default, it runs a `/bin/bash`, but can also be used to run a custom command:
 
 ```shell
diff --git a/plugins/common/functions b/plugins/common/functions
index 627172b89..5e919f620 100755
--- a/plugins/common/functions
+++ b/plugins/common/functions
@@ -321,7 +321,7 @@ get_app_running_container_types() {
   CONTAINER_TYPES="$(find "$DOKKU_ROOT/$APP" -maxdepth 1 -name "CONTAINER.*" -print0 | xargs -0)"
   if [[ -n "$CONTAINER_TYPES" ]]; then
     CONTAINER_TYPES="${CONTAINER_TYPES//$DOKKU_ROOT\/$APP\//}"
-    CONTAINER_TYPES="$(tr " " $'\n' <<< "$CONTAINER_TYPES" | awk -F. '{ print $2 }' | xargs)"
+    CONTAINER_TYPES="$(tr " " $'\n' <<< "$CONTAINER_TYPES" | awk -F. '{ print $2 }' | sort | uniq | xargs)"
   fi
 
   echo "$CONTAINER_TYPES"
diff --git a/plugins/enter/subcommands/default b/plugins/enter/subcommands/default
index 3e5008359..980bb2d33 100755
--- a/plugins/enter/subcommands/default
+++ b/plugins/enter/subcommands/default
@@ -7,26 +7,45 @@ enter_default_cmd() {
   local cmd="enter"
   local APP="$2"; local CONTAINER_TYPE="$3"; local IMAGE_TAG=$(get_running_image_tag "$APP"); local IMAGE=$(get_app_image_name "$APP" "$IMAGE_TAG")
   verify_app_name "$APP"
-  local AVAILABLE_CONTAINER_TYPES="$(get_app_running_container_types "$APP")"
+  local AVAILABLE_CONTAINER_TYPES=($(get_app_running_container_types "$APP"))
 
-  [[ ! -n "$3" ]] && dokku_log_warn "No container type specified." && dokku_log_fail "Available types for app ($APP): $AVAILABLE_CONTAINER_TYPES"
+  if [[ -z "$3" ]]; then
+    if [[ ${#AVAILABLE_CONTAINER_TYPES[@]} -gt 1 ]]; then
+      dokku_log_warn "No container type specified."
+      dokku_log_fail "Available types for app ($APP): ${AVAILABLE_CONTAINER_TYPES[@]}"
+    else
+      CONTAINER_TYPE="${AVAILABLE_CONTAINER_TYPES[0]}"
+    fi
+  fi
 
   if [[ "$3" == "--container-id" ]]; then
     local DOKKU_APP_CIDS=( $(get_app_container_ids "$APP") )
-    [[ ! -n "$4" ]] && dokku_log_warn "No container id specified." && dokku_log_fail "Available ids for app ($APP): ${DOKKU_APP_CIDS[@]}"
-
-    printf -- '%s\n' "${DOKKU_APP_CIDS[@]}" | grep -q -e "^$4" || dokku_log_fail "Invalid container id for app"
+    if [[ ! -n "$4" ]]; then
+      dokku_log_warn "No container id specified."
+      dokku_log_fail "Available ids for app ($APP): ${DOKKU_APP_CIDS[@]}"
+    fi
+    if ! (printf -- '%s\n' "${DOKKU_APP_CIDS[@]}" | grep -q -e "^$4"); then
+      dokku_log_warn "Invalid container id for app"
+      dokku_log_fail "Available ids for app ($APP): ${DOKKU_APP_CIDS[@]}"
+    fi
     local ID=$(printf -- '%s\n' "${DOKKU_APP_CIDS[@]}" | grep -e "^$4")
     shift 4
   else
     local DOKKU_APP_CIDS=( $(get_app_container_ids "$APP" "$CONTAINER_TYPE") )
     local ID=${DOKKU_APP_CIDS[0]}
-    [[ ! -n $ID ]] && dokku_log_fail "No containers found for type '$CONTAINER_TYPE'"
-    shift 3
+    if [[ ! -n $ID ]]; then
+      dokku_log_warn "No containers found for type '$CONTAINER_TYPE'"
+      dokku_log_fail "Available types for app ($APP): ${AVAILABLE_CONTAINER_TYPES[@]}"
+    fi
+    if [[ $3 ]]; then
+      shift 3
+    else
+      shift 2
+    fi
   fi
 
-  docker ps -aq --no-trunc | grep -e "^$ID" > /dev/null || dokku_log_fail "Container does not exist"
-  docker ps -q --no-trunc | grep -e "^$ID" > /dev/null || dokku_log_fail "Container is not running"
+  docker inspect "$ID" &> /dev/null || dokku_log_fail "Container does not exist"
+  docker inspect -f '{{ .State.Running }}' "$ID" | grep -q "true" > /dev/null || dokku_log_fail "Container is not running"
 
   local EXEC_CMD=""
   has_tty && local DOKKU_RUN_OPTS+=" -i -t"