Add remote autoscaler daemon endpoint support

buildbot-ext/buildbot_autoscale_ext/client.py

@@ -7,6 +7,7 @@ import socket
 import time
 from dataclasses import dataclass
 from typing import Any
+from urllib.parse import urlparse
 
 
 @dataclass(frozen=True)
@@ -45,10 +46,39 @@ class UnixSocketHTTPConnection(http.client.HTTPConnection):
 
 
 class DaemonClient:
-    def __init__(self, socket_path: str, retry_policy: RetryPolicy) -> None:
+    def __init__(
+        self,
+        *,
+        retry_policy: RetryPolicy,
+        socket_path: str | None = None,
+        base_url: str | None = None,
+        auth_token: str | None = None,
+    ) -> None:
+        if (socket_path is None) == (base_url is None):
+            raise ValueError("exactly one of socket_path or base_url must be set")
         self._socket_path = socket_path
+        self._base_url = base_url
+        self._auth_token = auth_token.strip() if auth_token is not None else None
         self._retry = retry_policy
 
+        self._base_path = ""
+        self._http_scheme = "http"
+        self._http_host = "localhost"
+        self._http_port = 80
+        if base_url is not None:
+            parsed = urlparse(base_url)
+            if parsed.scheme not in {"http", "https"}:
+                raise ValueError("base_url must use http or https scheme")
+            if parsed.hostname is None:
+                raise ValueError("base_url must include a hostname")
+            self._http_scheme = parsed.scheme
+            self._http_host = parsed.hostname
+            if parsed.port is not None:
+                self._http_port = parsed.port
+            elif parsed.scheme == "https":
+                self._http_port = 443
+            self._base_path = parsed.path.rstrip("/")
+
     def post_json(
         self,
         path: str,
@@ -136,12 +166,31 @@ class DaemonClient:
         timeout_seconds: float,
         payload: bytes | None,
     ) -> tuple[bytes, int]:
-        conn = UnixSocketHTTPConnection(self._socket_path, timeout=timeout_seconds)
+        request_path = path if path.startswith("/") else f"/{path}"
+        if self._base_path != "":
+            request_path = f"{self._base_path}{request_path}"
+
         headers = {"Accept": "application/json"}
         if payload is not None:
             headers["Content-Type"] = "application/json"
+        if self._auth_token is not None:
+            headers["Authorization"] = f"Bearer {self._auth_token}"
+
+        conn: http.client.HTTPConnection
+        if self._socket_path is not None:
+            conn = UnixSocketHTTPConnection(self._socket_path, timeout=timeout_seconds)
+        else:
+            conn = (
+                http.client.HTTPSConnection(
+                    self._http_host, self._http_port, timeout=timeout_seconds
+                )
+                if self._http_scheme == "https"
+                else http.client.HTTPConnection(
+                    self._http_host, self._http_port, timeout=timeout_seconds
+                )
+            )
         try:
-            conn.request(method=method, url=path, body=payload, headers=headers)
+            conn.request(method=method, url=request_path, body=payload, headers=headers)
             response = conn.getresponse()
             data = response.read()
             return data, response.status