Allow job handlers to be exempted from the default random choice pool.

lib/galaxy/config.py

@@ -193,6 +193,7 @@ class Configuration( object ):
         # Store advanced job management config
         self.job_manager = kwargs.get('job_manager', self.server_name).strip()
         self.job_handlers = [ x.strip() for x in kwargs.get('job_handlers', self.server_name).split(',') ]
+        self.default_job_handlers = [ x.strip() for x in kwargs.get('default_job_handlers', ','.join( self.job_handlers ) ).split(',') ]
         # Use database for IPC unless this is a standalone server (or multiple servers doing self dispatching in memory)
         self.track_jobs_in_database = True
         if ( len( self.job_handlers ) == 1 ) and ( self.job_handlers[0] == self.server_name ) and ( self.job_manager == self.server_name ):

lib/galaxy/tools/__init__.py

@@ -791,7 +791,7 @@ class Tool:
             self.parallelism = None
         # Set job handler(s). Each handler is a dict with 'url' and, optionally, 'params'.
         self_id = self.id.lower()
-        self.job_handlers = [ { "name" : name } for name in self.app.config.job_handlers ]
+        self.job_handlers = [ { "name" : name } for name in self.app.config.default_job_handlers ]
         # Set custom handler(s) if they're defined.
         if self_id in self.app.config.tool_handlers:
             self.job_handlers = self.app.config.tool_handlers[ self_id ]

universe_wsgi.ini.sample

@@ -562,6 +562,13 @@ use_interactive = True
 # comma-separated list.
 #job_handlers = main
 
+# By default, a handler from job_handlers will be selected at random if the
+# tool to run does specify a handler below in [galaxy:tool_handlers].  If you
+# want certain handlers to only handle jobs for tools/params explicitly
+# assigned below, use default_job_handlers to specify which handlers should be
+# used for jobs without explicit handlers.
+#default_job_handlers = main
+
 # This enables splitting of jobs into tasks, if specified by the particular tool config.
 # This is a new feature and not recommended for production servers yet.
 #use_tasked_jobs = False