__init__

uvm/firecracker/api.py

@@ -0,0 +1,82 @@
+"""Typed Firecracker HTTP requests over a per-VM Unix-domain socket."""
+
+from __future__ import annotations
+
+import http.client
+import json
+import socket
+from collections.abc import Mapping
+from pathlib import Path
+from typing import Any
+
+from ..errors import FirecrackerError
+
+
+class _UnixHTTPConnection(http.client.HTTPConnection):
+    def __init__(self, socket_path: Path, timeout: float) -> None:
+        super().__init__("localhost", timeout=timeout)
+        self._socket_path = socket_path
+
+    def connect(self) -> None:
+        self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        self.sock.settimeout(self.timeout)
+        self.sock.connect(str(self._socket_path))
+
+
+class FirecrackerClient:
+    """Keep Firecracker endpoint details out of lifecycle orchestration."""
+
+    def __init__(self, socket_path: Path, timeout_s: float) -> None:
+        self._socket_path = socket_path
+        self._timeout_s = timeout_s
+
+    def configure_and_start(self, config: Mapping[str, Any]) -> None:
+        machine = config["machine-config"]
+        boot = config["boot-source"]
+        drives = config["drives"]
+        interfaces = config["network-interfaces"]
+        if not isinstance(machine, Mapping) or not isinstance(boot, Mapping):
+            raise FirecrackerError("invalid Firecracker configuration")
+        if not isinstance(drives, list) or not drives:
+            raise FirecrackerError("Firecracker configuration has no root drive")
+        if not isinstance(interfaces, list) or not interfaces:
+            raise FirecrackerError("Firecracker configuration has no network interface")
+
+        self._request(
+            "PUT",
+            "/machine-config",
+            {
+                "vcpu_count": machine["vcpu_count"],
+                "mem_size_mib": machine["mem_size_mib"],
+                "smt": False,
+            },
+        )
+        self._request("PUT", "/boot-source", boot)
+        self._request("PUT", "/drives/rootfs", drives[0])
+        self._request("PUT", "/network-interfaces/eth0", interfaces[0])
+        self._request("PUT", "/actions", {"action_type": "InstanceStart"})
+
+    def _request(self, method: str, path: str, body: object) -> None:
+        payload = json.dumps(body).encode("utf-8")
+        connection = _UnixHTTPConnection(self._socket_path, self._timeout_s)
+        try:
+            connection.request(
+                method,
+                path,
+                payload,
+                {
+                    "Content-Type": "application/json",
+                    "Accept": "application/json",
+                },
+            )
+            response = connection.getresponse()
+            response_body = response.read().decode("utf-8", errors="replace")
+        except (OSError, http.client.HTTPException) as error:
+            raise FirecrackerError(f"Firecracker API {method} {path}: {error}") from error
+        finally:
+            connection.close()
+
+        if response.status >= 300:
+            raise FirecrackerError(
+                f"Firecracker API {method} {path}: {response.status} {response_body}"
+            )