feat(cli): add debugger host CLI flag to specify default base URL (#900)

libs/cli/langgraph_cli/cli.py

@@ -134,6 +134,12 @@
     type=int,
     help="Pull the debugger image locally and serve the UI on specified port",
 )
+OPT_DEBUGGER_BASE_URL = click.option(
+    "--debugger-base-url",
+    type=str,
+    help="URL used by the debugger to access LangGraph API. Defaults to http://127.0.0.1:[PORT]",
+)
+
 OPT_POSTGRES_URI = click.option(
     "--postgres-uri",
     help="Postgres URI to use for the database. Defaults to launching a local database",
@@ -152,6 +158,7 @@ def cli():
 @OPT_CONFIG
 @OPT_VERBOSE
 @OPT_DEBUGGER_PORT
+@OPT_DEBUGGER_BASE_URL
 @OPT_WATCH
 @OPT_POSTGRES_URI
 @click.option(
@@ -173,6 +180,7 @@ def up(
     wait: bool,
     verbose: bool,
     debugger_port: Optional[int],
+    debugger_base_url: Optional[str],
     postgres_uri: Optional[str],
 ):
     click.secho("Starting LangGraph API server...", fg="green")
@@ -193,6 +201,7 @@ def up(
             watch=watch,
             verbose=verbose,
             debugger_port=debugger_port,
+            debugger_base_url=debugger_base_url,
             postgres_uri=postgres_uri,
         )
         # add up + options
@@ -221,12 +230,15 @@ def on_stdout(line: str):
                     if debugger_port
                     else "https://smith.langchain.com"
                 )
+                debugger_base_url_query = (
+                    debugger_base_url or f"http://127.0.0.1:{port}"
+                )
                 set("")
                 sys.stdout.write(
                     f"""Ready!
 - API: http://localhost:{port}
 - Docs: http://localhost:{port}/docs
-- Debugger: {debugger_origin}/studio/?baseUrl=http://127.0.0.1:{port}
+- Debugger: {debugger_origin}/studio/?baseUrl={debugger_base_url_query}
 """
                 )
                 sys.stdout.flush()
@@ -449,13 +461,15 @@ def prepare_args_and_stdin(
     port: int,
     watch: bool,
     debugger_port: Optional[int] = None,
+    debugger_base_url: Optional[str] = None,
     postgres_uri: Optional[str] = None,
 ):
     # prepare args
     stdin = langgraph_cli.docker.compose(
         capabilities,
         port=port,
         debugger_port=debugger_port,
+        debugger_base_url=debugger_base_url,
         postgres_uri=postgres_uri,
     )
     args = [
@@ -487,6 +501,7 @@ def prepare(
     watch: bool,
     verbose: bool,
     debugger_port: Optional[int] = None,
+    debugger_base_url: Optional[str] = None,
     postgres_uri: Optional[str] = None,
 ):
     with open(config_path) as f:
@@ -510,6 +525,7 @@ def prepare(
         port=port,
         watch=watch,
         debugger_port=debugger_port,
+        debugger_base_url=debugger_base_url or f"http://127.0.0.1:{port}",
         postgres_uri=postgres_uri,
     )
     return args, stdin

libs/cli/langgraph_cli/docker.py

@@ -32,18 +32,6 @@
 """
 
 
-DEBUGGER = """
-    langgraph-debugger:
-        image: langchain/langgraph-debugger
-        restart: on-failure
-        ports:
-            - "{debugger_port}:3968"
-        depends_on:
-            langgraph-postgres:
-                condition: service_healthy
-"""
-
-
 class Version(NamedTuple):
     major: int
     minor: int
@@ -117,11 +105,38 @@ def check_capabilities(runner) -> DockerCapabilities:
     )
 
 
+def debugger_compose(
+    *, port: Optional[int] = None, base_url: Optional[str] = None
+) -> str:
+    if port is None:
+        return ""
+
+    compose_str = """
+    langgraph-debugger:
+        image: langchain/langgraph-debugger
+        restart: on-failure
+        depends_on:
+            langgraph-postgres:
+                condition: service_healthy
+        ports:
+            - "{port}:3968"
+"""
+
+    if base_url:
+        compose_str += """
+        environment:
+            VITE_STUDIO_LOCAL_GRAPH_URL: {base_url}
+"""
+
+    return compose_str.format(port=port, base_url=base_url)
+
+
 def compose(
     capabilities: DockerCapabilities,
     *,
     port: int,
     debugger_port: Optional[int] = None,
+    debugger_base_url: Optional[str] = None,
     # postgres://user:password@host:port/database?option=value
     postgres_uri: Optional[str] = None,
 ) -> str:
@@ -151,7 +166,7 @@ def compose(
 
     compose_str = f"""{volumes}services:
 {db}
-{DEBUGGER.format(debugger_port=debugger_port) if debugger_port else ""}
+{debugger_compose(port=debugger_port, base_url=debugger_base_url)}
     langgraph-api:
         ports:
             - "{port}:8000\""""

libs/cli/tests/unit_tests/test_cli.py

@@ -20,6 +20,7 @@ def test_prepare_args_and_stdin():
     )
     port = 8000
     debugger_port = 8001
+    debugger_graph_url = f"http://127.0.0.1:{port}"
 
     actual_args, actual_stdin = prepare_args_and_stdin(
         capabilities=DEFAULT_DOCKER_CAPABILITIES,
@@ -28,6 +29,7 @@ def test_prepare_args_and_stdin():
         docker_compose="custom-docker-compose.yml",
         port=port,
         debugger_port=debugger_port,
+        debugger_base_url=debugger_graph_url,
         watch=True,
     )
 
@@ -63,11 +65,13 @@ def test_prepare_args_and_stdin():
     langgraph-debugger:
         image: langchain/langgraph-debugger
         restart: on-failure
-        ports:
-            - "{debugger_port}:3968"
         depends_on:
             langgraph-postgres:
                 condition: service_healthy
+        ports:
+            - "{debugger_port}:3968"
+        environment:
+            VITE_STUDIO_LOCAL_GRAPH_URL: {debugger_graph_url}
     langgraph-api:
         ports:
             - "8000:8000"