Deprecate DATABASE_TYPE and use_database

Select a database by adding it to ENABLED_SERVICE like the other
services.  This greatly simplifies using the lib/* functions in
places other than stack.sh

Backward-compatibility is maintained or now (into havana at least).

Change-Id: I967e44603b4d69d5d70e1a75a9938172ca434025

README.md

@@ -60,11 +60,12 @@ You can override environment variables used in `stack.sh` by creating file name
 # Database Backend
 
 Multiple database backends are available. The available databases are defined in the lib/databases directory.
-To choose a database backend, add a line to your `localrc` like:
+`mysql` is the default database, choose a different one by putting the following in `localrc`:
 
-    use_database postgresql
+    disable_service mysql
+    enable_service postgresql
 
-By default, the mysql database backend is used.
+`mysql` is the default database.
 
 # RPC Backend
 

functions

@@ -975,9 +975,11 @@ function upload_image() {
 #  $1 The name of the database backend to use (mysql, postgresql, ...)
 function use_database {
     if [[ -z "$DATABASE_BACKENDS" ]]; then
-        # The backends haven't initialized yet, just save the selection for now
+        # No backends registered means this is likely called from ``localrc``
+        # This is now deprecated usage
         DATABASE_TYPE=$1
     else
+        # This should no longer get called...here for posterity
         use_exclusive_service DATABASE_BACKENDS DATABASE_TYPE $1
     fi
 }

lib/database

@@ -2,9 +2,12 @@
 # Interface for interacting with different database backends
 
 # Dependencies:
-# DATABASE_BACKENDS variable must contain a list of available database backends
+# ``ENABLED_SERVICES`` must be defined
-# DATABASE_TYPE variable must be set
 
+# ``DATABASE_BACKENDS`` will contain a list of available database backends
+# after sourcing this file.
+
+# This is a wrapper for the specific database backends available.
 # Each database must implement four functions:
 #   recreate_database_$DATABASE_TYPE
 #   install_database_$DATABASE_TYPE
@@ -23,8 +26,36 @@ function register_database {
     [ -z "$DATABASE_BACKENDS" ] && DATABASE_BACKENDS=$1 || DATABASE_BACKENDS+=" $1"
 }
 
+# Sourcing the database libs sets DATABASE_BACKENDS with the available list
 for f in $TOP_DIR/lib/databases/*; do source $f; done
 
+# If ``DATABASE_TYPE`` is defined here it's because the user has it in ``localrc``
+# or has called ``use_database``.  Both are deprecated so let's fix it up for now.
+if [[ -n $DATABASE_TYPE ]]; then
+    # This is now deprecated usage, set up a warning and try to be
+    # somewhat backward compatible for now.
+    DEPRECATED_TEXT="$DEPRECATED_TEXT\nThe database backend needs to be properly set in ENABLED_SERVICES; DATABASE_TYPE or use_database is deprecated localrc\n"
+    if [[ ! $ENABLED_SERVICES =~ $DATABASE_TYPE ]]; then
+        # It's not in enabled services but user has attempted to select a
+        # database, so just add it now
+        ENABLED_SERVICES+=,$DATABASE_TYPE
+        unset DATABASE_TYPE
+    fi
+fi
+
+# ``DATABASE_BACKENDS`` now contains a list of the supported databases
+# Look in ``ENABLED_SERVICES`` to see if one has been selected
+for db in $DATABASE_BACKENDS; do
+    # Set the type for the rest of the backend to use
+    if is_service_enabled $db; then
+        # Set this now for the rest of the database funtions
+        DATABASE_TYPE=$db
+    fi
+done
+# If ``DATABASE_TYPE`` is unset here no database was selected
+# This is not an error as multi-node installs will do this on the compute nodes
+
+
 # Set the database type based on the configuration
 function initialize_database_backends {
     for backend in $DATABASE_BACKENDS; do

stack.sh

@@ -99,11 +99,6 @@ fi
 source $TOP_DIR/lib/database
 source $TOP_DIR/lib/rpc_backend
 
-# Validate database selection
-# Since DATABASE_BACKENDS is now set, this also gets ENABLED_SERVICES
-# properly configured for the database selection.
-use_database $DATABASE_TYPE || echo "Invalid database '$DATABASE_TYPE'"
-
 # Remove services which were negated in ENABLED_SERVICES
 # using the "-" prefix (e.g., "-rabbit") instead of
 # calling disable_service().
@@ -430,13 +425,13 @@ FLAT_INTERFACE=${FLAT_INTERFACE-$GUEST_INTERFACE_DEFAULT}
 # Database Configuration
 # ----------------------
 
-# To select between database backends, add a line to localrc like:
+# To select between database backends, add the following to ``localrc``:
 #
-#  use_database postgresql
+#    disable_service mysql
+#    enable_service postgresql
 #
-# The available database backends are defined in the ``DATABASE_BACKENDS``
+# The available database backends are listed in ``DATABASE_BACKENDS`` after
-# variable defined in stackrc. By default, MySQL is enabled as the database
+# ``lib/database`` is sourced. ``mysql`` is the default.
-# backend.
 
 initialize_database_backends && echo "Using $DATABASE_TYPE database backend" || echo "No database enabled"
 
@@ -520,11 +515,11 @@ function echo_summary() {
         if [ ! -z "$LAST_SPINNER_PID" ]; then
             printf "\b\b\bdone\n" >&3
         fi
-        echo -n $@ >&6
+        echo -n -e $@ >&6
         spinner &
         LAST_SPINNER_PID=$!
     else
-        echo $@ >&6
+        echo -e $@ >&6
     fi
 }
 
@@ -1382,9 +1377,9 @@ fi
 # Echo ``HOST_IP`` - useful for ``build_uec.sh``, which uses dhcp to give the instance an address
 echo "This is your host ip: $HOST_IP"
 
-# Warn that ``EXTRA_FLAGS`` needs to be converted to ``EXTRA_OPTS``
+# Warn that a deprecated feature was used
-if [[ -n "$EXTRA_FLAGS" ]]; then
+if [[ -n "$DEPRECATED_TEXT" ]]; then
-    echo_summary "WARNING: EXTRA_FLAGS is defined and may need to be converted to EXTRA_OPTS"
+    echo_summary "WARNING: $DEPRECATED_TEXT"
 fi
 
 # Indicate how long this took to run (bash maintained variable ``SECONDS``)

stackrc

@@ -9,9 +9,6 @@ DEST=/opt/stack
 # Destination for working data
 DATA_DIR=${DEST}/data
 
-# Select the default database
-DATABASE_TYPE=mysql
-
 # Determine stack user
 if [[ $EUID -eq 0 ]]; then
     STACK_USER=stack
@@ -24,7 +21,7 @@ fi
 # ``disable_service`` functions in ``localrc``.
 # For example, to enable Swift add this to ``localrc``:
 # enable_service swift
-ENABLED_SERVICES=g-api,g-reg,key,n-api,n-crt,n-obj,n-cpu,n-net,n-cond,cinder,c-sch,c-api,c-vol,n-sch,n-novnc,n-xvnc,n-cauth,horizon,rabbit,tempest,$DATABASE_TYPE
+ENABLED_SERVICES=g-api,g-reg,key,n-api,n-crt,n-obj,n-cpu,n-net,n-cond,cinder,c-sch,c-api,c-vol,n-sch,n-novnc,n-xvnc,n-cauth,horizon,rabbit,tempest,mysql
 
 # Set the default Nova APIs to enable
 NOVA_ENABLED_APIS=ec2,osapi_compute,metadata