Remove linked app from links file when destroying app

.gitignore

@@ -1,2 +1,3 @@
 tests/dokku
 tests/fixtures
+tests/bin/plugn

functions

@@ -257,18 +257,13 @@ service_unlink() {
   local SERVICE="$1"
   local SERVICE_URL=$(service_url "$SERVICE")
   local SERVICE_NAME=$(get_service_name "$SERVICE")
-  local SERVICE_ROOT="$PLUGIN_DATA_ROOT/$SERVICE"
   local EXISTING_CONFIG=$(dokku config "$APP")
   local DATABASE_NAME=$(get_database_name "$SERVICE")
   local SERVICE_ALIAS=$(service_alias "$SERVICE")
   local LINK=($(echo "$EXISTING_CONFIG" | grep "$PLUGIN_SCHEME://.*/$DATABASE_NAME" | cut -d: -f1)) || true
-  local LINKS_FILE="$SERVICE_ROOT/LINKS"
 
   [[ -z ${LINK[*]} ]] && dokku_log_fail "Not linked to app $APP"
-  mkdir -p "$SERVICE_ROOT" || dokku_log_fail "Unable to create service directory"
-  touch "$LINKS_FILE"
-  sed -i "/^$APP\$/d" "$LINKS_FILE"
-  sort "$LINKS_FILE" -u -o "$LINKS_FILE"
+  remove_from_links_file "$SERVICE" "$APP"
 
   dokku docker-options:remove "$APP" build,deploy,run "--link $SERVICE_NAME:$SERVICE_ALIAS"
   dokku config:unset "$APP" "${LINK[*]}"
@@ -343,3 +338,15 @@ promote() {
   NEW_CONFIG_VARS+="$PLUGIN_DEFAULT_CONFIG_VAR=$PROMOTE_URL"
   dokku config:set "$APP" $NEW_CONFIG_VARS
 }
+
+remove_from_links_file() {
+  local SERVICE="$1"
+  local APP="$2"
+  local SERVICE_ROOT="$PLUGIN_DATA_ROOT/$SERVICE"
+  local LINKS_FILE="$SERVICE_ROOT/LINKS"
+
+  mkdir -p "$SERVICE_ROOT" || dokku_log_fail "Unable to create service directory"
+  touch "$LINKS_FILE"
+  sed -i "/^$APP\$/d" "$LINKS_FILE"
+  sort "$LINKS_FILE" -u -o "$LINKS_FILE"
+}

pre-delete

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+
+PLUGIN_BASE_PATH="$PLUGIN_PATH"
+if [[ -n $DOKKU_API_VERSION ]]; then
+  PLUGIN_BASE_PATH="$PLUGIN_ENABLED_PATH"
+fi
+source "$PLUGIN_BASE_PATH/common/functions"
+source "$(dirname "$0")/functions"
+source "$(dirname "$0")/config"
+
+APP="$1"
+for SERVICE in "$PLUGIN_DATA_ROOT"/*; do
+  remove_from_links_file "$(basename "$SERVICE")" "$APP"
+done
+exit 0

tests/bin/sudo

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+exit 0

tests/hook_pre_delete.bats

@@ -0,0 +1,20 @@
+#!/usr/bin/env bats
+load test_helper
+
+setup() {
+  dokku apps:create my_app >&2
+  dokku "$PLUGIN_COMMAND_PREFIX:create" l >&2
+  dokku "$PLUGIN_COMMAND_PREFIX:link" l my_app >&2
+}
+
+teardown() {
+  dokku "$PLUGIN_COMMAND_PREFIX:unlink" l my_app >&2
+  dokku --force "$PLUGIN_COMMAND_PREFIX:destroy" l >&2
+  rm "$DOKKU_ROOT/my_app" -rf
+}
+
+@test "($PLUGIN_COMMAND_PREFIX:hook:pre-delete) removes app from links file when destroying app" {
+  [[ -n $(< "$PLUGIN_DATA_ROOT/l/LINKS") ]]
+  dokku --force apps:destroy my_app
+  [[ -z $(< "$PLUGIN_DATA_ROOT/l/LINKS") ]]
+}

tests/setup.sh

@@ -1,6 +1,8 @@
 #!/usr/bin/env bash
 source "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/test_helper.bash"
 
+BIN_STUBS="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/bin"
+
 if [[ ! -d $DOKKU_ROOT ]]; then
   git clone https://github.com/progrium/dokku.git $DOKKU_ROOT > /dev/null
 fi
@@ -13,3 +15,10 @@ cd -
 rm -rf $DOKKU_ROOT/plugins/service
 mkdir -p $DOKKU_ROOT/plugins/service
 find ./ -maxdepth 1 -type f -exec cp '{}' $DOKKU_ROOT/plugins/service \;
+
+if [[ ! -f $BIN_STUBS/plugn ]]; then
+  wget -O- "$PLUGN_URL" | tar xzf - -C "$BIN_STUBS"
+  plugn init
+  ln -s "$DOKKU_ROOT"/plugins/* "$DOKKU_ROOT"/plugins/available
+  ln -s "$DOKKU_ROOT"/plugins/* "$DOKKU_ROOT"/plugins/enabled
+fi

tests/test_helper.bash

@@ -10,6 +10,7 @@ export PLUGIN_AVAILABLE_PATH="$PLUGIN_PATH"
 export PLUGIN_CORE_AVAILABLE_PATH="$PLUGIN_PATH"
 export POSTGRES_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/fixtures"
 export PLUGIN_DATA_ROOT="$POSTGRES_ROOT"
+export PLUGN_URL="https://github.com/progrium/plugn/releases/download/v0.1.0/plugn_0.1.0_linux_x86_64.tgz"
 
 mkdir -p "$PLUGIN_DATA_ROOT"
 rm -rf "${PLUGIN_DATA_ROOT:?}"/*