Added server assisted roaming capability

src/sender/soundsender.py

@@ -5,8 +5,9 @@ import logging
 from datetime import datetime
 import requests
 from .abcsender import AbcSender
-from utils import config
+from utils import config, LoopingTimer
 from urllib.parse import urljoin
+import time
 
 """
 Send a sound sample
@@ -23,6 +24,87 @@ class SoundSender(AbcSender):
     SoundSender class, responsible for sending sound samples to the cloud.
     """
 
+    def __init__(self):
+
+        self._feed_url = None
+        self._reassign_timer = None
+        if not config.NO_AUTODISCOVER:
+            retry = 0
+            timeout = 30
+            while True:
+                try:
+                    r = requests.post(
+                        urljoin(config.API_URL, "/assignment"),
+                        json={"device_id": config.DEVICE_ID},
+                        timeout=timeout
+                    )
+                except requests.exceptions.Timeout:
+                    logging.warning(f"/assignment timed out after {timeout} sec! Retrying...")
+                    continue
+
+                if r.status_code not in [200, 404]:
+                    logging.warning(
+                        f"Unexpected status code while acquiring an assignment: {r.status_code}. Retrying..."
+                    )
+                    time.sleep(5)
+                    continue
+
+                if r.status_code == 404:
+                    logging.info(
+                        "/assignment returned 404 error. Assuming missing capability... Defaulting to use API_URL"
+                    )
+                    self._feed_url = config.API_URL
+                    break
+
+                if r.json()['hard_default']:
+                    retry += 1
+                    if retry < 10:
+                        logging.info(f"Still waiting for non hard-default url... Attempt {retry}/10")
+                        time.sleep(6)
+                        continue
+                    else:
+                        logging.info(f"Given up waiting for non hard-default url... accepting hard default.")
+
+                logging.info(f"Assigned to {r.json()['site']}")
+                self._feed_url = r.json()['url']
+                break
+
+            self._reassign_timer = LoopingTimer(config.REASSIGN_INTERVAL, lambda: self.reassign())
+            self._reassign_timer.start()
+
+        # If the above block failed to assign a feed_url
+        if not self._feed_url:
+            logging.info("Using API_URL as feed url")
+            self._feed_url = config.API_URL
+
+    def reassign(self):
+        logging.debug("Asking for reassign...")
+        timeout = 30
+        try:
+            r = requests.post(
+                urljoin(config.API_URL, "/assignment"),
+                json={"device_id": config.DEVICE_ID},
+                timeout=timeout
+            )
+        except requests.exceptions.Timeout:
+            logging.warning(f"/assignment timed out after {timeout} sec! Ignoring...")
+            return
+
+        if r.status_code == 404:
+            logging.debug("/assignment returned 404 status code. Assuming missing capability, and doing nothing...")
+            return
+
+        if r.status_code != 200:
+            logging.debug(f"/assignment returned {r.status_code} status code. Ignoring...")
+            return
+
+        logging.debug(f"Received assignment to {r.json()['site']}")
+
+        if r.json()['url'] != self._feed_url:
+            logging.info(f"Reassigned to {r.json()['site']}!")
+            # Because of GIL and because this is a reference, we don't really have to be careful assigning this
+            self._feed_url = r.json()['url']
+
     def sendvalue(self, value: str, decision: bool) -> None:
         """
         Send a sound sample to the cloud.
@@ -32,14 +114,24 @@ class SoundSender(AbcSender):
         """
         if decision:
             files = {
-                "file": (os.path.basename(value), open(value, 'rb').read(), 'audio/wave',
+                "file": (
-                         {'Content-length': os.path.getsize(value)}),
+                    os.path.basename(value),
+                    open(value, 'rb').read(),
+                    'audio/wave',
+                    {'Content-length': os.path.getsize(value)}
+                ),
                 "description": (
-                    None, json.dumps({'date': datetime.now().isoformat(), 'device_id': config.DEVICE_ID}),
+                    None,
-                    "application/json")
+                    json.dumps({'date': datetime.now().isoformat(), 'device_id': config.DEVICE_ID}),
+                    "application/json"
+                )
             }
 
-            r = requests.post(urljoin(config.API_URL, config.FEED_TYPE), files=files)
+            r = requests.post(urljoin(self._feed_url, config.FEED_TYPE), files=files)
             logging.debug(f"Content: {r.content.decode()}")
             logging.debug(f"Headers: {r.headers}")
             r.raise_for_status()
+
+    def __del__(self):
+        if self._reassign_timer:
+            self._reassign_timer.stop()

src/utils/config.py

@@ -41,3 +41,8 @@ FEED_TYPE = os.environ.get("FEED_TYPE", "input") # probably the worst naming the
 
 if FEED_TYPE not in ['input', 'filter']:
     raise ValueError("FEED_TYPE must be either input or filter")
+
+# Skip fetching /assignment endpoint
+NO_AUTODISCOVER = os.environ.get("NO_AUTODISCOVER", 'no').lower() in ['yes', '1', 'true']
+
+REASSIGN_INTERVAL = int(os.environ.get("REASSIGN_INTERVAL", 120))