Split table definitions from db configuration.

r2/example.ini

@@ -183,48 +183,67 @@ hardcache_categories = *:hc:hc
 db_app_name = reddit
 # are we allowed to create tables?
 db_create_tables = True
+# are we allowed to write at all?
+disallow_db_writes = False
 
 type_db = main
 rel_type_db = main
 hardcache_db = main
 
-db_table_link = thing, main, main
-db_table_account = thing, main
-db_table_message = thing, main
+# definitions of what each table is (probably shouldn't change in .update files)
+# things require no extra info. relation is followed by the names of the related tables
+db_table_link = thing
+db_table_account = thing
+db_table_message = thing
+db_table_savehide = relation, account, link
+db_table_click = relation, account, link
+db_table_comment = thing
+db_table_subreddit = thing
+db_table_srmember = relation, subreddit, account
+db_table_friend = relation, account, account
+db_table_vote_account_link = relation, account, link
+db_table_vote_account_comment = relation, account, comment
+db_table_inbox_account_comment = relation, account, comment
+db_table_inbox_account_message = relation, account, message
+db_table_moderatorinbox = relation, subreddit, message
+db_table_report_account_link = relation, account, link
+db_table_report_account_comment = relation, account, comment
+db_table_report_account_message = relation, account, message
+db_table_report_account_subreddit = relation, account, subreddit
+db_table_award = thing
+db_table_trophy = relation, account, award
+db_table_jury_account_link = relation, account, link
+db_table_ad = thing
+db_table_adsr = relation, ad, subreddit
+db_table_flair = relation, subreddit, account
 
-db_table_savehide = relation, account, link, main
-db_table_click = relation, account, link, main
-
-db_table_comment = thing, comment
-db_table_subreddit = thing, comment
-
-db_table_srmember = relation, subreddit, account, comment
-
-db_table_friend = relation, account, account, comment
-
-db_table_vote_account_link = relation, account, link, vote
-db_table_vote_account_comment = relation, account, comment, vote
-
-db_table_inbox_account_comment = relation, account, comment, main
-db_table_inbox_account_message = relation, account, message, main
-db_table_moderatorinbox = relation, subreddit, message, main
-
-db_table_report_account_link = relation, account, link, main
-db_table_report_account_comment = relation, account, comment, comment
-db_table_report_account_message = relation, account, message, main
-db_table_report_account_subreddit = relation, account, subreddit, main
-
-db_table_award = thing, award
-db_table_trophy = relation, account, award, award
-
-db_table_jury_account_link = relation, account, link, main
-
-db_table_ad = thing, main
-db_table_adsr = relation, ad, subreddit, main
-
-db_table_flair = relation, subreddit, account, main
-
-disallow_db_writes = False
+# which servers to find each table on (likely to change in .update files)
+# first server listed is assumed to be the master, all others are read-only slaves
+# additionally, a "!avoid_master" flag may be added to specify that reads should use the slaves
+db_servers_link = main, main
+db_servers_account = main
+db_servers_message = main
+db_servers_savehide = main
+db_servers_click = main
+db_servers_comment = comment
+db_servers_subreddit = comment
+db_servers_srmember = comment
+db_servers_friend = comment
+db_servers_vote_account_link = vote
+db_servers_vote_account_comment = vote
+db_servers_inbox_account_comment = main
+db_servers_inbox_account_message = main
+db_servers_moderatorinbox = main
+db_servers_report_account_link = main
+db_servers_report_account_comment = comment
+db_servers_report_account_message = main
+db_servers_report_account_subreddit = main
+db_servers_award = award
+db_servers_trophy = award
+db_servers_jury_account_link = main
+db_servers_ad = main
+db_servers_adsr = main
+db_servers_flair = main
 
 
 ## -- traffic analytics --

r2/r2/lib/app_globals.py

@@ -487,19 +487,22 @@ class Globals(object):
 
         prefix = 'db_table_'
         for k, v in self.config.raw_data.iteritems():
-            if k.startswith(prefix):
-                params = list(ConfigValue.to_iter(v))
-                name = k[len(prefix):]
-                kind = params[0]
-                if kind == 'thing':
-                    engines, flags = split_flags(params[1:])
-                    dbm.add_thing(name, dbm.get_engines(engines),
-                                  **flags)
-                elif kind == 'relation':
-                    engines, flags = split_flags(params[3:])
-                    dbm.add_relation(name, params[1], params[2],
-                                     dbm.get_engines(engines),
-                                     **flags)
+            if not k.startswith(prefix):
+                continue
+
+            params = tuple(ConfigValue.to_iter(v))
+            name = k[len(prefix):]
+            kind = params[0]
+            server_list = self.config.raw_data["db_servers_" + name]
+            engines, flags = split_flags(ConfigValue.to_iter(server_list))
+
+            if kind == 'thing':
+                dbm.add_thing(name, dbm.get_engines(engines),
+                              **flags)
+            elif kind == 'relation':
+                dbm.add_relation(name, params[1], params[2],
+                                 dbm.get_engines(engines),
+                                 **flags)
         return dbm
 
     def __del__(self):