First registration shouldn't block the application using SBA

When pyctuator is starting up, it starts sending periodic registration
requests to SBA. Currently, the first registration is done on the "main
thread" while subsequent registrations are done asynchronously (using
a "daemonic" `threading.Timer()`.

If the registration's HTTP request is stuck until timing out, this blocks
the application until the this timeout.

Instead, all registration attempts, including the first one, should be
done asynchronously.

See #51

Author: michael.yak

examples/Advanced/pyproject.toml

@@ -11,7 +11,7 @@ python = "^3.7"
 psutil = { version = "^5.6" }
 fastapi = { version = "^0.41.0" }
 uvicorn = { version = "^0.9.0" }
-pyctuator = { version = "^0.13.4" }
+pyctuator = { version = "^0.13.5" }
 sqlalchemy = { version = "^1.3" }
 PyMySQL = { version = "^0.9.3" }
 cryptography = { version = "^2.8" }

examples/FastAPI/pyproject.toml

@@ -11,7 +11,7 @@ python = "^3.7"
 psutil = { version = "^5.6" }
 fastapi = { version = "^0.41.0" }
 uvicorn = { version = "^0.9.0" }
-pyctuator = { version = "^0.13.4" }
+pyctuator = { version = "^0.13.5" }
 
 [build-system]
 requires = ["poetry>=0.12"]

examples/Flask/pyproject.toml

@@ -10,7 +10,7 @@ authors = [
 python = "^3.7"
 psutil = { version = "^5.6" }
 flask = { version = "^1.1" }
-pyctuator = { version = "^0.13.4" }
+pyctuator = { version = "^0.13.5" }
 
 [build-system]
 requires = ["poetry>=0.12"]

examples/aiohttp/pyproject.toml

@@ -10,7 +10,7 @@ authors = [
 python = "^3.7"
 psutil = { version = "^5.6" }
 aiohttp = { version = "^3.5.4" }
-pyctuator = { version = "^0.13.4" }
+pyctuator = { version = "^0.13.5" }
 
 [build-system]
 requires = ["poetry>=0.12"]

examples/tornado/pyproject.toml

@@ -10,7 +10,7 @@ authors = [
 python = "^3.7"
 psutil = { version = "^5.6" }
 tornado = { version = "^6.0.4" }
-pyctuator = { version = "^0.13.4" }
+pyctuator = { version = "^0.13.5" }
 
 [build-system]
 requires = ["poetry>=0.12"]

pyctuator/impl/spring_boot_admin_registration.py

@@ -24,7 +24,7 @@ def __init__(
             pyctuator_base_url: str,
             start_time: datetime,
             service_url: str,
-            registration_interval_sec: int,
+            registration_interval_sec: float,
             application_metadata: Optional[dict] = None
     ) -> None:
         self.registration_url = registration_url
@@ -41,7 +41,7 @@ def __init__(
         self.disable_certificate_validation_for_https_registration: bool = \
             os.getenv("PYCTUATOR_REGISTRATION_NO_CERT") is not None
 
-    def _schedule_next_registration(self, registration_interval_sec: int) -> None:
+    def _schedule_next_registration(self, registration_interval_sec: float) -> None:
         timer = threading.Timer(
             registration_interval_sec,
             self._register_with_admin_server,
@@ -66,8 +66,7 @@ def _register_with_admin_server(self) -> None:
             }
         }
 
-        logging.debug("Trying to post registration data to %s: %s",
-                      self.registration_url, registration_data)
+        logging.debug("Trying to post registration data to %s: %s", self.registration_url, registration_data)
 
         conn: Optional[HTTPConnection] = None
         try:
@@ -123,11 +122,11 @@ def authenticate(self, headers: Dict) -> None:
             encoded_authorization: str = b64encode(bytes(authorization_string, "utf-8")).decode("ascii")
             headers["Authorization"] = f"Basic {encoded_authorization}"
 
-    def start(self) -> None:
+    def start(self, initial_delay_sec: float = None) -> None:
         logging.info("Starting recurring registration of %s with %s",
                      self.pyctuator_base_url, self.registration_url)
         self.should_continue_registration_schedule = True
-        self._register_with_admin_server()
+        self._schedule_next_registration(initial_delay_sec or self.registration_interval_sec)
 
     def stop(self) -> None:
         logging.info("Stopping recurring registration")

pyctuator/pyctuator.py

@@ -33,7 +33,7 @@ def __init__(
             registration_url: Optional[str],
             registration_auth: Optional[Auth] = None,
             app_description: Optional[str] = None,
-            registration_interval_sec: int = 10,
+            registration_interval_sec: float = 10,
             free_disk_space_down_threshold_bytes: int = 1024 * 1024 * 100,
             logfile_max_size: int = 10000,
             logfile_formatter: str = default_logfile_format,

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pyctuator"
-version = "0.13.4"
+version = "0.13.5"
 description = "A Python implementation of the Spring Actuator API for popular web frameworks"
 authors = [
     "Michael Yakobi <[email protected]>",

tests/test_spring_boot_admin_registration.py

@@ -1,3 +1,4 @@
+import time
 from datetime import datetime
 from typing import Optional, Any
 
@@ -13,7 +14,7 @@ def test_registration_no_auth(registration_tracker: RegistrationTrackerFixture)
     registration_handler = get_registration_handler("http://localhost:8001/register", None)
 
     try:
-        registration_handler.start()
+        _start_registration(registration_handler)
         assert registration_tracker.count == 1
 
     finally:
@@ -25,7 +26,7 @@ def test_registration_basic_auth_no_creds(registration_tracker: RegistrationTrac
     registration_handler = get_registration_handler("http://localhost:8001/register-with-basic-auth", None)
 
     try:
-        registration_handler.start()
+        _start_registration(registration_handler)
         assert registration_tracker.count == 0
 
         error_message = "Failed registering with boot-admin, got %s - %s"
@@ -46,7 +47,7 @@ def test_registration_basic_auth_bad_creds(registration_tracker: RegistrationTra
     )
 
     try:
-        registration_handler.start()
+        _start_registration(registration_handler)
         assert registration_tracker.count == 0
 
         error_message = "Failed registering with boot-admin, got %s - %s"
@@ -67,7 +68,7 @@ def test_registration_basic_auth(registration_tracker: RegistrationTrackerFixtur
     )
 
     try:
-        registration_handler.start()
+        _start_registration(registration_handler)
         assert registration_tracker.count == 1
 
     finally:
@@ -84,3 +85,11 @@ def get_registration_handler(registration_url: str, registration_auth: Optional[
         service_url="http://whatever/service",
         registration_interval_sec=100
     )
+
+
+def _start_registration(registration_handler: BootAdminRegistrationHandler) -> None:
+    # Registration is done asynchronously, for the test, ask to register shortly after start is called
+    registration_handler.start(0.01)
+
+    # Wait enough after starting the registration allowing the async registration to happen.
+    time.sleep(0.1)