LangServe

.github/workflows/langserve_ci.yml

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+---
+name: libs/langserve CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    paths:
+      - '.github/actions/poetry_setup/action.yml'
+      - '.github/tools/**'
+      - '.github/workflows/_lint.yml'
+      - '.github/workflows/_test.yml'
+      - '.github/workflows/langserve_ci.yml'
+      - 'libs/langserve/**'
+  workflow_dispatch:  # Allows to trigger the workflow manually in GitHub UI
+
+# If another push to the same PR or branch happens while this workflow is still running,
+# cancel the earlier run in favor of the next run.
+#
+# There's no point in testing an outdated version of the code. GitHub only allows
+# a limited number of job runners to be active at the same time, so it's better to cancel
+# pointless jobs early so that more useful jobs can run sooner.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  POETRY_VERSION: "1.5.1"
+  WORKDIR: "libs/langserve"
+
+jobs:
+  lint:
+    uses:
+      ./.github/workflows/_lint.yml
+    with:
+      working-directory: libs/langserve
+    secrets: inherit
+
+  test:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ${{ env.WORKDIR }}
+    strategy:
+      matrix:
+        python-version:
+          - "3.8"
+          - "3.9"
+          - "3.10"
+          - "3.11"
+    name: Python ${{ matrix.python-version }} extended tests
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Python ${{ matrix.python-version }} + Poetry ${{ env.POETRY_VERSION }}
+        uses: "./.github/actions/poetry_setup"
+        with:
+          python-version: ${{ matrix.python-version }}
+          poetry-version: ${{ env.POETRY_VERSION }}
+          working-directory: libs/langserve
+          cache-key: langserve-all
+
+      - name: Install dependencies
+        shell: bash
+        run: |
+          echo "Running extended tests, installing dependencies with poetry..."
+          poetry install --with test,lint --extras all
+
+      - name: Run tests
+        run: make test
+
+      - name: Ensure the tests did not create any additional files
+        shell: bash
+        run: |
+          set -eu
+
+          STATUS="$(git status)"
+          echo "$STATUS"
+
+          # grep will exit non-zero if the target message isn't found,
+          # and `set -e` above will cause the step to fail.
+          echo "$STATUS" | grep 'nothing to commit, working tree clean'

libs/langserve/LICENSE

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+MIT License
+
+Copyright (c) 2023 LangChain
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

libs/langserve/Makefile

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+.PHONY: all lint format test help
+
+# Default target executed when no arguments are given to make.
+all: help
+
+######################
+# TESTING AND COVERAGE
+######################
+
+# Define a variable for the test file path.
+TEST_FILE ?= tests/unit_tests/
+
+test:
+	poetry run pytest --disable-socket --allow-unix-socket $(TEST_FILE)
+
+######################
+# LINTING AND FORMATTING
+######################
+
+# Define a variable for Python and notebook files.
+PYTHON_FILES=.
+lint format: PYTHON_FILES=.
+lint_diff format_diff: PYTHON_FILES=$(shell git diff --relative=libs/langserve --name-only --diff-filter=d master | grep -E '\.py$$|\.ipynb$$')
+
+lint lint_diff:
+	poetry run ruff .
+	poetry run black $(PYTHON_FILES) --check
+
+format format_diff:
+	poetry run black $(PYTHON_FILES)
+	poetry run ruff --select I --fix $(PYTHON_FILES)
+
+spell_check:
+	poetry run codespell --toml pyproject.toml
+
+spell_fix:
+	poetry run codespell --toml pyproject.toml -w
+
+######################
+# HELP
+######################
+
+help:
+	@echo '===================='
+	@echo '-- LINTING --'
+	@echo 'format                       - run code formatters'
+	@echo 'lint                         - run linters'
+	@echo 'spell_check                 	- run codespell on the project'
+	@echo 'spell_fix                		- run codespell on the project and fix the errors'
+	@echo '-- TESTS --'
+	@echo 'coverage                     - run unit tests and generate coverage report'
+	@echo 'test                         - run unit tests'
+	@echo 'test TEST_FILE=<test_file>   - run all tests in file'
+	@echo '-- DOCUMENTATION tasks are from the top-level Makefile --'

libs/langserve/README.md

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+# LangServe 🦜️🔗 
+
+## Overview
+
+`LangServe` is a library that allows developers to host their Langchain runnables / 
+call into them remotely from a runnable interface.
+
+## Examples
+
+For more examples, see the [examples](./examples) directory.
+
+### Server
+
+```python
+#!/usr/bin/env python
+from fastapi import FastAPI
+from langchain.prompts import ChatPromptTemplate
+from langchain.chat_models import ChatAnthropic, ChatOpenAI
+from langserve import add_routes
+from typing_extensions import TypedDict
+
+
+app = FastAPI(
+  title="LangChain Server",
+  version="1.0",
+  description="A simple api server using Langchain's Runnable interfaces",
+)
+
+
+# Serve Open AI and Anthropic models
+LLMInput = Union[List[Union[SystemMessage, HumanMessage, str]], str]
+
+add_routes(
+    app,
+    ChatOpenAI(),
+    path="/openai",
+    input_type=LLMInput,
+    config_keys=[],
+)
+add_routes(
+    app,
+    ChatAnthropic(),
+    path="/anthropic",
+    input_type=LLMInput,
+    config_keys=[],
+)
+
+# Serve a joke chain
+class ChainInput(TypedDict):
+    """The input to the chain."""
+
+    topic: str
+    """The topic of the joke."""
+
+model = ChatAnthropic()
+prompt = ChatPromptTemplate.from_template("tell me a joke about {topic}")
+add_routes(app, prompt | model, path="/chain", input_type=ChainInput)
+
+if __name__ == "__main__":
+    import uvicorn
+
+    uvicorn.run(app, host="localhost", port=8000)
+```
+
+
+### Client
+
+```python
+
+from langchain.schema import SystemMessage, HumanMessage
+from langchain.prompts import ChatPromptTemplate
+from langchain.schema.runnable import RunnableMap
+from langserve import RemoteRunnable
+
+openai = RemoteRunnable("http://localhost:8000/openai/")
+anthropic = RemoteRunnable("http://localhost:8000/anthropic/")
+joke_chain = RemoteRunnable("http://localhost:8000/chain/")
+
+joke_chain.invoke({"topic": "parrots"})
+
+# or async
+await joke_chain.ainvoke({"topic": "parrots"})
+
+prompt = [
+    SystemMessage(content='Act like either a cat or a parrot.'), 
+    HumanMessage(content='Hello!')
+]
+
+# Supports astream
+async for msg in anthropic.astream(prompt):
+    print(msg, end="", flush=True)
+
+prompt = ChatPromptTemplate.from_messages(
+    [("system", "Tell me a long story about {topic}")]
+)
+
+# Can define custom chains
+chain = prompt | RunnableMap({
+    "openai": openai,
+    "anthropic": anthropic,
+})
+
+chain.batch([{ "topic": "parrots" }, { "topic": "cats" }])
+```
+
+## Installation
+
+```bash
+# pip install langserve[all] -- has not been published to pypi yet
+```
+
+or use `client` extra for client code, and `server` extra for server code.
+
+## Features
+
+- Deploy runnables with FastAPI
+- Client can use remote runnables almost as if they were local
+    - Supports async
+    - Supports batch
+    - Supports stream
+
+### Limitations
+
+- Chain callbacks cannot be passed from the client to the server

libs/langserve/__init__.py

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+from .client import RemoteRunnable
+from .server import add_routes
+
+__all__ = ["RemoteRunnable", "add_routes"]