Read DATABASE_ADAPTER variable from app when setting DATABASE_URL

README.md

@@ -129,3 +129,30 @@ dokku mysql:clone lolipop new_database
 # finally, you can destroy the container
 dokku mysql:destroy lolipop
 ```
+
+## Changing database adapter
+
+It's possible to change the protocol for DATABASE_URL by setting
+the environment variable DATABASE_ADAPTER on the app:
+
+```
+dokku config:set lolipop DATABASE_ADAPTER=mysql2
+dokku mysql:link lolipop playground
+```
+
+Will cause DATABASE_URL to be set as
+mysql2://mysql:SOME_PASSWORD@dokku-mysql-lolipop:3306/lolipop
+
+CAUTION: Changing DATABASE_ADAPTER after linking will cause dokku to believe
+the service is not linked when attempting to use `dokku mysql:unlink` or
+`dokku mysql:promote`.
+You should be able to fix this by
+
+- Changing DATABASE_URL manually to the new value.
+
+OR
+
+- Set DATABASE_ADAPTER back to its original setting
+- Unlink the service
+- Change DATABASE_ADAPTER to the desired setting
+- Relink the service

functions

@@ -70,6 +70,7 @@ service_exposed_ports() {
 service_link() {
   local APP="$2"
   local SERVICE="$1"
+  update_plugin_scheme_for_app "$APP"
   local SERVICE_URL=$(service_url "$SERVICE")
   local SERVICE_NAME=$(get_service_name "$SERVICE")
   local SERVICE_ROOT="$PLUGIN_DATA_ROOT/$SERVICE"
@@ -253,6 +254,7 @@ service_stop() {
 service_unlink() {
   local APP="$2"
   local SERVICE="$1"
+  update_plugin_scheme_for_app "$APP"
   local SERVICE_URL=$(service_url "$SERVICE")
   local SERVICE_NAME=$(get_service_name "$SERVICE")
   local EXISTING_CONFIG=$(dokku config "$APP")
@@ -309,6 +311,7 @@ promote() {
   local APP="$2"
   local PLUGIN_DEFAULT_CONFIG_VAR="${PLUGIN_DEFAULT_ALIAS}_URL"
   local EXISTING_CONFIG=$(dokku config "$APP")
+  update_plugin_scheme_for_app "$APP"
   local SERVICE_URL=$(service_url "$SERVICE")
   local CONFIG_VARS=($(echo "$EXISTING_CONFIG" | grep "$SERVICE_URL" | cut -d: -f1)) || true
   local PREVIOUS_DEFAULT_URL=$(get_url_from_config "$EXISTING_CONFIG" "$PLUGIN_DEFAULT_CONFIG_VAR")
@@ -350,3 +353,9 @@ service_linked_apps() {
 
   tr '\n' ' ' < "$LINKS_FILE"
 }
+
+update_plugin_scheme_for_app() {
+  local APP=$1
+  local DATABASE_ADAPTER=$(dokku config:get $APP DATABASE_ADAPTER)
+  PLUGIN_SCHEME=${DATABASE_ADAPTER:-$PLUGIN_SCHEME}
+}

tests/service_link.bats

@@ -59,3 +59,12 @@ teardown() {
   assert_contains "${lines[*]}" "--link dokku.mysql.l:dokku-mysql-l"
   dokku "$PLUGIN_COMMAND_PREFIX:unlink" l my_app
 }
+
+@test "($PLUGIN_COMMAND_PREFIX:link) uses apps DATABASE_ADAPTER variable" {
+  dokku config:set my_app DATABASE_ADAPTER=mysql2
+  dokku "$PLUGIN_COMMAND_PREFIX:link" l my_app
+  url=$(dokku config:get my_app DATABASE_URL)
+  password="$(cat "$PLUGIN_DATA_ROOT/l/PASSWORD")"
+  assert_contains "$url" "mysql2://mysql:$password@dokku-mysql-l:3306/l"
+  dokku "$PLUGIN_COMMAND_PREFIX:unlink" l my_app
+}

tests/service_promote.bats

@@ -53,3 +53,11 @@ teardown() {
   run dokku config my_app
   assert_contains "${lines[*]}" "DOKKU_MYSQL_"
 }
+
+@test "($PLUGIN_COMMAND_PREFIX:promote) uses DATABASE_ADAPTER variable" {
+  password="$(cat "$PLUGIN_DATA_ROOT/l/PASSWORD")"
+  dokku config:set my_app "DATABASE_ADAPTER=mysql2" "DATABASE_URL=mysql://u:p@host:3306/db" "DOKKU_MYSQL_BLUE_URL=mysql2://mysql:$password@dokku-mysql-l:3306/l"
+  dokku "$PLUGIN_COMMAND_PREFIX:promote" l my_app
+  url=$(dokku config:get my_app DATABASE_URL)
+  assert_contains "$url" "mysql2://mysql:$password@dokku-mysql-l:3306/l"
+}