feat(cli): add langgraph deploy (#7004)

Allow users to deploy to langsmith deployments from the langgraph-cli.
This PR makes the following changes:
1. Add a simple host backend client with httpx
2. Adjust `progress.py` to show elapsed time for commands, and also use
threading.Event to stop the spinner
3. Adjust `_build` to allow arbitrary command so we can pass `docker
buildx build` and default to `docker build`
4. Add new `deploy` command, this re-uses a lot of the `langgraph build`
functionality, and then uses the new host-backend client to push the
built image to langsmith deployments.

---------

Co-authored-by: David Asamu <david.asamu@langchain.dev>

libs/cli/langgraph_cli/host_backend.py

@@ -0,0 +1,107 @@
+"""HTTP client for LangGraph host backend deployments."""
+
+from __future__ import annotations
+
+from typing import Any
+
+import click
+import httpx
+
+
+class HostBackendError(click.ClickException):
+    """Raised when the host backend returns an error response."""
+
+    def __init__(self, message: str, status_code: int | None = None):
+        super().__init__(message)
+        self.status_code = status_code
+
+
+class HostBackendClient:
+    """Minimal JSON HTTP client for the host backend deployment service."""
+
+    def __init__(self, base_url: str, api_key: str, tenant_id: str | None = None):
+        if not base_url:
+            raise click.UsageError("Host backend URL is required")
+        transport = httpx.HTTPTransport(retries=3)
+        headers: dict[str, str] = {
+            "X-Api-Key": api_key,
+            "Accept": "application/json",
+        }
+        if tenant_id:
+            headers["X-Tenant-ID"] = tenant_id
+        self._base_url = base_url.rstrip("/")
+        self._api_key = api_key
+        self._client = httpx.Client(
+            base_url=self._base_url,
+            headers=headers,
+            transport=transport,
+            timeout=30,
+        )
+
+    def _request(
+        self, method: str, path: str, payload: dict[str, Any] | None = None
+    ) -> Any:
+        try:
+            resp = self._client.request(method, path, json=payload)
+            resp.raise_for_status()
+        except httpx.HTTPStatusError as err:
+            detail = err.response.text or str(err.response.status_code)
+            raise HostBackendError(
+                f"{method} {path} failed with status {err.response.status_code}: {detail}",
+                status_code=err.response.status_code,
+            ) from None
+        except httpx.TransportError as err:
+            raise HostBackendError(str(err)) from None
+
+        if not resp.content:
+            return None
+        try:
+            return resp.json()
+        except ValueError as err:
+            raise HostBackendError(
+                f"Failed to decode response from {path}: {err}"
+            ) from None
+
+    def create_deployment(self, payload: dict[str, Any]) -> dict[str, Any]:
+        return self._request("POST", "/v2/deployments", payload)
+
+    def list_deployments(self, name_contains: str) -> dict[str, Any]:
+        return self._request("GET", f"/v2/deployments?name_contains={name_contains}")
+
+    def get_deployment(self, deployment_id: str) -> dict[str, Any]:
+        return self._request("GET", f"/v2/deployments/{deployment_id}")
+
+    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(
+        self,
+        deployment_id: str,
+        image_uri: str,
+        secrets: list[dict[str, str]] | None = None,
+    ) -> dict[str, Any]:
+        payload: dict[str, Any] = {
+            "source_revision_config": {"image_uri": image_uri},
+        }
+        if secrets is not None:
+            payload["secrets"] = secrets
+        return self._request(
+            "PATCH",
+            f"/v2/deployments/{deployment_id}",
+            payload,
+        )
+
+    def list_revisions(self, deployment_id: str, limit: int = 1) -> dict[str, Any]:
+        return self._request(
+            "GET",
+            f"/v2/deployments/{deployment_id}/revisions?limit={limit}",
+        )
+
+    def get_revision(self, deployment_id: str, revision_id: str) -> dict[str, Any]:
+        return self._request(
+            "GET",
+            f"/v2/deployments/{deployment_id}/revisions/{revision_id}",
+        )