Make ping count/delay configurable

* Adds `float` type to allowed value types
* Modifies `entrypoints.run_as_ping` to use new config options
* Modifies controller.send_directive` to use a new param named
  `expected_responses`, which allows us to stop waiting for more
  responses after the set # is received (defaults to 1 response)

Author: jimi-c

receptor/config.py

@@ -181,6 +181,20 @@ def __init__(self, args=None):
             value_type='path',
             hint='Path to control socket for controller commands.',
         )
+        self.add_config_option(
+            section='ping',
+            key='count',
+            default_value=0,
+            value_type='int',
+            hint='Number of pings to send. If unspecified here or in a config file pings will be continuously sent until interrupted.',
+        )
+        self.add_config_option(
+            section='ping',
+            key='delay',
+            default_value=0,
+            value_type='float',
+            hint='The delay (in seconds) to wait between pings. If unspecified here or in a config file pings will be sent as soon as the previous response is received.',
+        )
         self.add_config_option(
             section='ping',
             key='recipient',
@@ -360,6 +374,8 @@ def _enforce_value_type(self, value, value_type):
                 return value_type(value)
             elif value_type == 'int' and not isinstance(value, int):
                 return int(value)
+            elif value_type == 'float' and not isinstance(value, float):
+                return float(value)
             elif value_type == 'str' and not isinstance(value, str):
                 return '%s' % (value,)
             elif value_type == 'bool' and not isinstance(value, bool):

receptor/controller.py

@@ -1,25 +1,27 @@
 import asyncio
 import logging
+import os
 import socket
 import sys
-import os
 
 from . import protocol
 
 logger = logging.getLogger(__name__)
 
 
-def send_directive(directive, recipient, payload, socket_path):
+def send_directive(directive, recipient, payload, socket_path, expected_responses=1):
     if payload == '-':
         payload = sys.stdin.read()
     sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
     sock.connect(socket_path)
     sock.sendall(f"{recipient}\n{directive}\n{payload}".encode('utf-8') + protocol.DELIM)
     response = b''
-    while True:
+    response_count = 0
+    while response_count < expected_responses:
         response = sock.recv(4096)
         sys.stdout.buffer.write(response + b"\n")
         sys.stdout.flush()
+        response_count += 1
 
 # FIXME: the socket path is in the config, it shouldn't need to be passed as an arg here
 def mainloop(receptor, socket_path, loop=asyncio.get_event_loop()):

receptor/entrypoints.py

@@ -1,5 +1,6 @@
 import datetime
 import logging
+import time
 
 from .receptor import Receptor
 from . import node
@@ -17,7 +18,14 @@ def run_as_controller(config):
 def run_as_ping(config):
     logger.info(f'Sending ping to {config.ping_recipient}.')
     now = datetime.datetime.utcnow()
-    controller.send_directive('receptor:ping', config.ping_recipient, now.isoformat(), config.ping_socket_path)
+    pings_sent = 0
+    while True:
+        controller.send_directive('receptor:ping', config.ping_recipient, now.isoformat(), config.ping_socket_path)
+        pings_sent += 1
+        if config.ping_count != 0 and pings_sent >= config.ping_count:
+            break
+        elif config.ping_delay > 0.0:
+            time.sleep(config.ping_delay)
 
 
 def run_as_send(config):