Add config option daemon.default_workers

This option will determine the default number of workers that are
started by the `verdi daemon start` command. Specifying an explicit
value as argument will of course still override this.

aiida/cmdline/commands/cmd_daemon.py

@@ -25,8 +25,11 @@
 from aiida.manage.configuration import get_config
 
 
-def validate_positive_non_zero_integer(ctx, param, value):  # pylint: disable=unused-argument,invalid-name
-    """Validate that `value` is a positive integer."""
+def validate_daemon_workers(ctx, param, value):  # pylint: disable=unused-argument,invalid-name
+    """Validate the value for the number of daemon workers to start with default set by config."""
+    if value is None:
+        value = ctx.obj.config.get_option('daemon.default_workers', ctx.obj.profile.name)
+
     if not isinstance(value, int):
         raise click.BadParameter('{} is not an integer'.format(value))
 
@@ -43,11 +46,15 @@ def verdi_daemon():
 
 @verdi_daemon.command()
 @click.option('--foreground', is_flag=True, help='Run in foreground.')
-@click.argument('number', default=1, type=int, callback=validate_positive_non_zero_integer)
+@click.argument('number', required=False, type=int, callback=validate_daemon_workers)
 @decorators.with_dbenv()
 @decorators.check_circus_zmq_version
 def start(foreground, number):
-    """Start the daemon with NUMBER workers [default=1]."""
+    """Start the daemon with NUMBER workers.
+
+    If the NUMBER of desired workers is not specified, the default is used, which is determined by the configuration
+    option `daemon.default_workers`, which if not explicitly changed defaults to 1.
+    """
     from aiida.engine.daemon.client import get_daemon_client
 
     client = get_daemon_client()
@@ -196,8 +203,8 @@ def restart(ctx, reset, no_wait):
     """Restart the daemon.
 
     By default will only reset the workers of the running daemon. After the restart the same amount of workers will be
-    running. If the `--reset` flag is passed, however, the full circus daemon will be stopped and restarted with just
-    a single worker.
+    running. If the `--reset` flag is passed, however, the full daemon will be stopped and restarted with the default
+    number of workers that is started when calling `verdi daemon start` manually.
     """
     from aiida.engine.daemon.client import get_daemon_client
 
@@ -223,7 +230,7 @@ def restart(ctx, reset, no_wait):
 
 @verdi_daemon.command(hidden=True)
 @click.option('--foreground', is_flag=True, help='Run in foreground.')
-@click.argument('number', default=1, type=int, callback=validate_positive_non_zero_integer)
+@click.argument('number', required=False, type=int, callback=validate_daemon_workers)
 @decorators.with_dbenv()
 @decorators.check_circus_zmq_version
 def start_circus(foreground, number):

aiida/manage/configuration/options.py

@@ -14,6 +14,7 @@
 __all__ = ('get_option', 'get_option_names', 'parse_option')
 
 NO_DEFAULT = ()
+DEFAULT_DAEMON_WORKERS = 1
 DEFAULT_DAEMON_TIMEOUT = 20  # Default timeout in seconds for circus client calls
 VALID_LOG_LEVELS = ['CRITICAL', 'ERROR', 'WARNING', 'REPORT', 'INFO', 'DEBUG']
 
@@ -30,6 +31,14 @@
         'description': 'The polling interval in seconds to be used by process runners',
         'global_only': False,
     },
+    'daemon.default_workers': {
+        'key': 'daemon_default_workers',
+        'valid_type': 'int',
+        'valid_values': None,
+        'default': DEFAULT_DAEMON_WORKERS,
+        'description': 'The default number of workers to be launched by `verdi daemon start`',
+        'global_only': False,
+    },
     'daemon.timeout': {
         'key': 'daemon_timeout',
         'valid_type': 'int',

docs/source/verdi/verdi_user_guide.rst

@@ -316,7 +316,7 @@ Below is a list with all available subcommands.
       incr     Add NUMBER [default=1] workers to the running daemon.
       logshow  Show the log of the daemon, press CTRL+C to quit.
       restart  Restart the daemon.
-      start    Start the daemon with NUMBER workers [default=1].
+      start    Start the daemon with NUMBER workers.
       status   Print the status of the current daemon or all daemons.
       stop     Stop the daemon.
 

tests/cmdline/commands/test_daemon.py

@@ -8,7 +8,6 @@
 # For further information please visit http://www.aiida.net               #
 ###########################################################################
 """Tests for `verdi daemon`."""
-
 from click.testing import CliRunner
 import pytest