feat: add langgraph deploy command

libs/cli/langgraph_cli/host_backend.py

@@ -0,0 +1,79 @@
+"""HTTP client for LangGraph host backend deployments."""
+
+from __future__ import annotations
+
+import json
+import urllib.error
+import urllib.request
+from typing import Any
+
+import click
+
+
+class HostBackendError(click.ClickException):
+    """Raised when the host backend returns an error response."""
+
+
+class HostBackendClient:
+    """Minimal JSON HTTP client for the host backend deployment service."""
+
+    def __init__(self, base_url: str, api_key: str):
+        if not base_url:
+            raise click.UsageError("Host backend URL is required")
+        base_url = base_url.rstrip("/")
+        self._base_url = base_url
+        self._api_key = api_key
+
+    def _request(
+        self, method: str, path: str, payload: dict[str, Any] | None = None
+    ) -> Any:
+        url = f"{self._base_url}{path}"
+        data: bytes | None
+        if payload is not None:
+            data = json.dumps(payload).encode("utf-8")
+        else:
+            data = None
+        headers = {
+            "Content-Type": "application/json",
+            "X-Api-Key": self._api_key,
+            "Accept": "application/json",
+        }
+        req = urllib.request.Request(url, data=data, headers=headers, method=method)
+        try:
+            with urllib.request.urlopen(req) as resp:  # noqa: S310
+                body = resp.read()
+        except urllib.error.HTTPError as err:
+            detail = err.read().decode("utf-8", errors="ignore")
+            message = detail or err.reason
+            raise HostBackendError(
+                f"{method} {path} failed with status {err.code}: {message}"
+            ) from None
+        except urllib.error.URLError as err:
+            raise HostBackendError(str(err.reason)) from None
+
+        if not body:
+            return None
+        try:
+            return json.loads(body)
+        except json.JSONDecodeError as err:
+            raise HostBackendError(
+                f"Failed to decode response from {path}: {err.msg}"
+            ) from None
+
+    def create_deployment(self, payload: dict[str, Any]) -> dict[str, Any]:
+        return self._request("POST", "/v2/deployments", payload)
+
+    def request_push_token(self, deployment_id: str) -> dict[str, Any]:
+        return self._request(
+            "POST",
+            f"/v2/deployments/{deployment_id}/push-token",
+        )
+
+    def update_deployment_image(
+        self, deployment_id: str, image_uri: str
+    ) -> dict[str, Any]:
+        return self._request(
+            "PATCH",
+            f"/v2/deployments/{deployment_id}",
+            {"source_revision_config": {"image_uri": image_uri}},
+        )