feat(host-agent): add control plane client

apps/device-host-agent/host_agent/config.py

@@ -19,16 +19,21 @@ class HostAgentConfig:
     poll_timeout_seconds: float = 20.0
     retry_backoff_seconds: float = 1.0
     max_retry_backoff_seconds: float = 30.0
+    max_retry_attempts: int = 5
 
 
 def load_host_agent_config(
     env: Mapping[str, str] | None = None,
 ) -> HostAgentConfig:
     values = os.environ if env is None else env
-    control_plane_url = values.get(
-        "HOST_AGENT_CONTROL_PLANE_URL",
-        "http://127.0.0.1:8001",
-    ).strip().rstrip("/")
+    control_plane_url = (
+        values.get(
+            "HOST_AGENT_CONTROL_PLANE_URL",
+            "http://127.0.0.1:8001",
+        )
+        .strip()
+        .rstrip("/")
+    )
     parsed_url = urlparse(control_plane_url)
     if parsed_url.scheme not in {"http", "https"} or not parsed_url.netloc:
         raise HostAgentConfigurationError(
@@ -66,6 +71,11 @@ def load_host_agent_config(
             "HOST_AGENT_MAX_RETRY_BACKOFF_SECONDS",
             30.0,
         ),
+        max_retry_attempts=_positive_int(
+            values,
+            "HOST_AGENT_MAX_RETRY_ATTEMPTS",
+            5,
+        ),
     )
     if config.max_retry_backoff_seconds < config.retry_backoff_seconds:
         raise HostAgentConfigurationError(
@@ -89,3 +99,20 @@ def _positive_float(
     if value <= 0:
         raise HostAgentConfigurationError(f"{name} must be greater than zero")
     return value
+
+
+def _positive_int(
+    values: Mapping[str, str],
+    name: str,
+    default: int,
+) -> int:
+    raw_value = values.get(name)
+    if raw_value is None:
+        return default
+    try:
+        value = int(raw_value)
+    except ValueError as exc:
+        raise HostAgentConfigurationError(f"{name} must be an integer") from exc
+    if value <= 0:
+        raise HostAgentConfigurationError(f"{name} must be greater than zero")
+    return value