feat: Add langgraph orchestration (#447)

Langgraph is introduced in langchain v0.2.0. The legacy langchain agent
(implemented in the `langchain-tools` orchestration) is deprecated in
langchain v0.2.0 and will soon be removed in the newer version of
langchain.

This PR adds a new orchestration - langgraph

.github/sync-repo-settings.yaml

@@ -36,6 +36,7 @@ branchProtectionRules:
       - "retrieval-service-alloydb-pr (retrieval-app-testing)"
       - "retrieval-service-cloudsql-pg-pr (retrieval-app-testing)"
       - "llm-demo-langchain-tools-pr (retrieval-app-testing)"
+      - "llm-demo-langgraph-pr (retrieval-app-testing)"
       - "llm-demo-vertexai-fc-pr (retrieval-app-testing)"
 # Set team access
 permissionRules:

llm_demo/app.py

@@ -188,6 +188,8 @@ async def decline_flight(request: Request):
     """Handler for LangChain chat requests"""
     # Note in the history, that the ticket was not booked
     # This is helpful in case of reloads so there doesn't seem to be a break in communication.
+    orchestrator = request.app.state.orchestrator
+    response = await orchestrator.user_session_decline_ticket(request.session["uuid"])
     request.session["history"].append(
         {"type": "ai", "data": {"content": "Please confirm if you would like to book."}}
     )

llm_demo/langgraph.int.tests.cloudbuild.yaml

@@ -0,0 +1,80 @@
+# Copyright 2024 Google LLC
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+steps:
+  - id: "Deploy to Cloud Run"
+    name: "gcr.io/cloud-builders/gcloud:latest"
+    dir: llm_demo
+    script: |
+        #!/usr/bin/env bash
+        gcloud run deploy ${_SERVICE} \
+          --source . \
+          --region ${_REGION} \
+          --no-allow-unauthenticated \
+          --update-env-vars ORCHESTRATION_TYPE=${_ORCHESTRATION_TYPE}
+
+  - id: "Test Frontend"
+    name: "gcr.io/cloud-builders/gcloud:latest"
+    entrypoint: /bin/bash
+    env: # Set env var expected by app
+    args:
+      - "-c"
+      - |
+        export URL=$(gcloud run services describe ${_SERVICE} --region ${_REGION} --format 'value(status.url)')
+        export ID_TOKEN=$(gcloud auth print-identity-token --audiences $$URL)
+        export ORCHESTRATION_TYPE=${_ORCHESTRATION_TYPE}
+
+        # Test `/` route
+        curl -c cookies.txt -si --fail --show-error -H "Authorization: Bearer $$ID_TOKEN" $$URL
+
+        # Test `/chat` route should fail
+        msg=$(curl -si --show-error \
+          -X POST \
+          -H "Authorization: Bearer $$ID_TOKEN" \
+          -H 'Content-Type: application/json' \
+          -d '{"prompt":"How can you help me?"}' \
+          $$URL/chat)
+
+        if grep -q "400" <<< "$msg"; then
+          echo "Chat Handler Test: PASSED"
+        else
+          echo "Chat Handler Test: FAILED"
+          echo $msg && exit 1
+        fi
+
+        # Test `/chat` route
+        curl -b cookies.txt -si --fail --show-error \
+          -X POST \
+          -H "Authorization: Bearer $$ID_TOKEN" \
+          -H 'Content-Type: application/json' \
+          -d '{"prompt":"How can you help me?"}' \
+          $$URL/chat
+
+  - id: "Delete image and service"
+    name: "gcr.io/cloud-builders/gcloud"
+    script: |
+        #!/usr/bin/env bash
+        gcloud artifacts docker images delete $_GCR_HOSTNAME/$PROJECT_ID/cloud-run-source-deploy/$_SERVICE --quiet
+        gcloud run services delete ${_SERVICE} --region ${_REGION} --quiet
+
+serviceAccount: "projects/$PROJECT_ID/serviceAccounts/548341735270-compute@developer.gserviceaccount.com" # Necessary for ID token creation
+options:
+  automapSubstitutions: true
+  logging: CLOUD_LOGGING_ONLY # Necessary for custom service account
+  dynamic_substitutions: true
+
+substitutions:
+  _GCR_HOSTNAME: ${_REGION}-docker.pkg.dev
+  _SERVICE: demo-service-${BUILD_ID}
+  _REGION: us-central1
+  _ORCHESTRATION_TYPE: langgraph

llm_demo/orchestrator/__init__.py

@@ -12,12 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from . import langchain_tools, vertexai_function_calling
+from . import langchain_tools, langgraph, vertexai_function_calling
 from .orchestrator import BaseOrchestrator, createOrchestrator
 
 __ALL__ = [
     "BaseOrchestrator",
     "createOrchestrator",
     "langchain_tools",
     "vertexai_function_calling",
+    "langgraph",
 ]

llm_demo/orchestrator/langchain_tools/langchain_tools_orchestrator.py

@@ -16,7 +16,7 @@
 import os
 import uuid
 from datetime import datetime
-from typing import Any, Dict, List
+from typing import Any, Dict, List, Optional
 
 from aiohttp import ClientSession, TCPConnector
 from fastapi import HTTPException
@@ -127,6 +127,13 @@ async def user_session_insert_ticket(self, uuid: str, params: str) -> Any:
         response = await user_session.insert_ticket(params)
         return response
 
+    async def user_session_decline_ticket(self, uuid: str) -> Optional[dict[str, Any]]:
+        """
+        Used if there's a process to be done after user decline ticket.
+        Return None is nothing is needed to be done.
+        """
+        return None
+
     async def check_and_add_confirmations(self, response: Dict[str, Any]):
         for step in response.get("intermediate_steps") or []:
             if len(step) > 0:

llm_demo/orchestrator/langgraph/__init__.py

@@ -0,0 +1,17 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .langgraph_orchestrator import LangGraphOrchestrator
+
+__ALL__ = ["LangGraphOrchestrator"]