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This guide provides a step-by-step guide to implement, publish, deploy and run your custom agentic service using Ray and Kodosumi.

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Background information

We will implement an agent utilising OpenAI to find news for a single or multiple companies operationalising the following LLM prompt:
Identify news from {{start}} to {{end}} about company “{{name}}”. Format the output as a bullet point list in the following format: * YYYY-mm-dd - [**Headline**](Link): Brief Summary of the news. Only output the bullet point list about news in the specified date range. Do not include any other text or additional information. If you cannot find any news for the given date range then output the text “no news found”.

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Development workflow overview

The development process with Kodosumi consists of two main work streams:
  1. Implementing the Entrypoint The entrypoint serves as the foundation of your service, housing the core business logic. It acts as the central hub for distributed computing, where complex calculations or third party system requests are broken down and distributed across multiple processing units using Ray. This component is responsible for orchestrating parallel tasks and ensuring efficient resource utilization.
  2. Implementing the Endpoint The endpoint establishes the HTTP interface for user interaction, providing a structured way to receive and process user input. It implements comprehensive input validation and manages the entire service lifecycle. This component is crucial for launching and monitoring the execution flow of your service.
Together, these components form a robust architecture that enables the creation of scalable and efficient agentic services. The entrypoint handles the computational complexity, while the endpoint ensures reliable user interaction and service management.

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Step-by-step implementation guide

We start implementing the service with the folder package structure and the build of the query function.

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1. Create git remote

Create a public repository to host your agentic service. Ensure you have write access. For this example we use the following repository URL:

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2. Create Python Virtual Environment

Create and source a Python Virtual Environment with your system Python executable. python3 -m venv .venv source .venv/bin/activate
You need to locate the Python system executable. Depending on your operating system and setup this location differs.

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3. Clone the repository

Clone the repository to your localhost: 
    git clone https://github.com/plan-net/agentic-workflow-example.git
    cd agentic-workflow-example/

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4. Setup project structure

Create a new directory ./company_news inside your local working directory ./agentic-workflow-example to host your package. 
mkdir ./company_news
Use the flat package layout. The flat layout simplifies the deployment process as we will see later in deployment. In contrast to the src layout the the flat layout does not need any additional installation step to be importable by Python.
Add the basic package structure and create the usual suspects along with query.py to deliver the agentic service. 
touch ./company_news/__init__.py
touch ./.gitignore
touch ./.env
Open ./.gitignore and paste the following listing: 
__pycache__/
data/*
.env
.venv
Open ./.env and add your OpenAI api key: 
OPENAI_API_KEY=<add your key>
You need to have an OpenAI API key to run this example. Push our initial commit: git add . git commit -m “initial version” git push

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5. Install Kodosumi

Install Kodosumi from PyPi pip install kodosumi Or clone the latest dev trunk from Kodosumi at GitHub git clone https://github.com/masumi-network/kodosumi cd kodosumi git checkout dev pip install . cd .. rm -Rf kodosumi

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6. Start ray

Start Ray on your localhost. Load .env into the environment variables before dotenv run — ray start —head

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7. Implement and test query

Implement the query function in ./company_news/query.py. 
import datetime

from jinja2 import Template
from openai import OpenAI


def query(text: str, 
          start: datetime.datetime, 
          end: datetime.datetime) -> dict:
    template = Template("""
    Identify news from {{start}} to {{end}} about company **"{{name}}"**. 
    Format the output as a bullet point list in the following format:

    * YYYY-mm-dd - [**Headline**](Link): Brief Summary of the news.
                        
    Only output the bullet point list about news in the specified date range. 
    Do not include any other text or additional information. If you cannot find 
    any news for the given date range then output the text "no news found".    
    """)
    try:
        resp = chat(
            template.render(
                start=start.strftime("%Y-%m-%d"),
                end=end.strftime("%Y-%m-%d"),
                name=text)
        )
        return {**resp, **{
            "query": text,
            "start": start,
            "end": end,
            "error": None,
        }}
    except Exception as e:
        return {
            "query": text,
            "start": start,
            "end": end,
            "error": e
        }
This method uses jinja2 templating system to build a prompt with parameters text, start, and end and forwards the request to chat function. Add the chat function at the end of query.py. 
def chat(query: str, model="gpt-4o-mini"):
    t0 = datetime.datetime.now()
    client = OpenAI()
    response = client.responses.create(
        model=model,
        tools=[{"type": "web_search_preview"}],
        input=query
    )
    runtime = datetime.datetime.now() - t0
    return {
        "response": response.model_dump(),
        "output": response.output_text,
        "model": model,
        "runtime": runtime.total_seconds()
    }
At this stage and in query.py we use jinja2 which has been installed with kodosumi and openai which needs to be installed first: pip install openai Test the query function with a Python interactive interpreter 
import datetime
from company_news.query import query
from dotenv import load_dotenv

load_dotenv()
result = query(text="Serviceplan", 
                start=datetime.datetime(2024, 1, 1), 
                end=datetime.datetime(2024, 12, 31))
print(result["output"])

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8. Distribute query

In this next step you decorate query as a @ray.remote function and implement a driver function batch to process multiple concurrent queries with Ray. 
import ray

@ray.remote
def query(text: str, 
          start: datetime.datetime, 
          end: datetime.datetime) -> dict:
    ...
The driver function batchconsumes a List of str and triggers a chat request with OpenAI for each refined query string. 
from typing import List

def batch(texts: List[str],
          start: datetime.datetime,
          end: datetime.datetime):

    refined = [t.strip() for t in texts if t.strip()]
    futures = [query.remote(t, start, end) for t in refined]
    remaining_futures = futures.copy()
    completed_jobs = 0
    results = []

    while remaining_futures:
        done_futures, remaining_futures = ray.wait(
            remaining_futures, num_returns=1)
        result = ray.get(done_futures[0])
        results.append(result)
        completed_jobs += 1
        p = completed_jobs / len(texts) * 100.
        print(f"{result['query']}\n{completed_jobs}/{len(texts)} = {p:.0f}%")
        if result["error"]:
            print(f"**Error:** {result['error']}")
        else:
            print(result["output"])

    return results
The .remote() statement forwards batch execution to Ray and creates futures to wait for. futures = [query.remote(t, start, end) for t in refined] Test batch processing with 
import datetime
from dotenv import load_dotenv
import ray
from company_news.query import batch

load_dotenv()
ray.init()
result = batch(texts=["Serviceplan", "Plan.Net", "Mediaplus"], 
               start=datetime.datetime(2018, 1, 1), 
               end=datetime.datetime(2018, 1, 31))
print(result)

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9. Setup app

We now proceed to setup the app with an endpoint to interact with your service. For the simplicity of this example we add the endpoint implementation directly into query.py. At the end of query.py, set up the basic application structure: 
from kodosumi.core import ServeAPI
app = ServeAPI()
The ServeAPI() initialization creates a FastAPI application with Kodosumi-specific extensions. It provides automatic OpenAPI documentation, error handling, authentication and access control, input validation, and some configuration management. The app instance will be used to define the service endpoint with @app.enter and to define service meta data following OpenAPI specification. We will do this in step 11 of this guide. Before we specify the inputs model.

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10. Define inputs model

Define the user interface of your service with the help of the forms module. Import forms elements from kodosumi.core. See forms overview on the supported form input elements. 
from kodosumi.core import forms as F

news_model = F.Model(
    F.Markdown("""
    # Search News
    Specify the _query_ - for example the name of your client, the start and end date. You can specify multiple query. Type one query per line.
    """),
    F.Break(),
    F.InputArea(label="Query", name="texts"),
    F.InputDate(label="Start Date", name="start", required=True),
    F.InputDate(label="End Date", name="end", required=True),
    F.Submit("Submit"),
    F.Cancel("Cancel")
)
A simple form is rendered that displays a headline with some introductionary text, followed by a text area for the queries and a start and end date input field.

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11. Implement endpoint

Implement the HTTP endpoint using the @enter decorator of the ServeAPI instance app. We will attach the input model defined in the previous step and declare key OpenAPI and extra properties (summary, description, and tags, version, author for example). On top of ServeAPI and forms we import Launch to start execution within the endpoint and InputsError for form validation and error handling. Kodosumi Tracer will be used to log results and debug message. We import asyncio and some typing which we will need later. 
import fastapi
from kodosumi.core import InputsError
from kodosumi.core import Launch
from kodosumi.core import Tracer
import asyncio
from typing import Optional, List
Specify the endpoint function enter with 
@app.enter(
    path="/",
    model=news_model,
    summary="News Search",
    description="Search for news.",
    tags=["OpenAI"],
    version="1.0.0",
    author="[email protected]")
async def enter(request: fastapi.Request, inputs: dict):
    # parse and cleanse inputs
    query = inputs.get("texts", "").strip()
    start = datetime.datetime.strptime(inputs.get("start"), "%Y-%m-%d")
    end = datetime.datetime.strptime(inputs.get("end"), "%Y-%m-%d")
    texts = [s.strip() for s in query.split("\n") if s.strip()]
    # validate inputs
    error = InputsError()
    if not texts:
        error.add(texts="Please specify a query to search for news.")
    if start > end:
        error.add(start="Must be before or equal to end date.")
    if error.has_errors():
        raise error
    # launch execution
    return Launch(
        request, 
        "company_news.query:run_batch", 
        inputs={"texts": texts, "start": start, "end": end}
    )
The method consists of three parts:
  1. the inputs are parsed and cleansed
  2. the inputs are validated
  3. the execution is launched
The Launch object adresses function run_batch in company_news.query which we implement later.

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12. Create ingress deployment

Finish Ray serve setup and apply the Ray @serve.deployment and @serve.ingress decorators to create an ingress deployment. The @serve.deployment decorator is used to convert a Python class into a Deployment in Ray Serve. A deployment in Ray Serve is a group of actors that can handle traffic. It is defined as a single class with a number of options, including the number of “replicas” of the deployment, each of which will map to a Ray actor at runtime. Requests to a deployment are load balanced across its replicas. The @serve.ingress decorator is used to wrap a deployment class with an application derived from FastAPI for HTTP request parsing. It defines the HTTP handling logic for the application and can route to other deployments or call into them using the DeploymentHandle API. 
from ray import serve

@serve.deployment
@serve.ingress(app)
class NewsSearch: pass

fast_app = NewsSearch.bind()
The fast_app object is passed to Ray serve for deployment. We will use the module/object factory string company_news.query:fast_app to configure and run deployments.

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13. Refactor batch

But before, we wrap the entrypoint to batch into a function run_batch to convert inputs and pass the research request. 
async def run_batch(inputs: dict, tracer: Tracer):
    texts = inputs.get("texts", [])
    start = inputs.get("start", datetime.datetime.now())
    end = inputs.get("end", datetime.datetime.now())
    return await batch(texts, start, end, tracer)
Last but not least we refactor the batch function to be async. Add an updated version of batch at the end of query.py and remove the “old” function batch further up in file query.py. 
async def batch(texts: List[str], 
                start: datetime.datetime, 
                end: datetime.datetime,
                tracer: Optional[Tracer]=None):
    refined = [t.strip() for t in texts if t.strip()]
    futures = [query.remote(t, start, end) for t in refined]
    unready = futures.copy()
    completed_jobs = 0
    results = []
    while unready:
        ready, unready = ray.wait(unready, num_returns=1, timeout=1)
        if ready:
            result = ray.get(ready[0])
            results.append(result)
            completed_jobs += 1
            p = completed_jobs / len(texts) * 100.
            await tracer.markdown(f"#### {result['query']}")
            await tracer.markdown(f"{completed_jobs}/{len(texts)} = {p:.0f}%")
            if result["error"]:
                await tracer.markdown(f"**Error:** {result['error']}")
            else:
                await tracer.markdown(result["output"])
            await tracer.html("<div class='large-divider'></div>")
            print(f"Job completed ({completed_jobs}/{len(texts)})")
        await asyncio.sleep(1)
    return results
If you carefully watch the function signature you recognise inputs and tracer. Both arguments are injected by the Kodosumi Launch mechanic and carry the inputs arguments from the user and a kodosumi.core.Tracer object. Use this object to add markdown, text and other results to flow execution. The tracer will be passed to batch. A slightly modified batch function uses the tracer to create result markdown notes and stdio output.

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14. Test with uvicorn

We test the app in query.py with uvicorn uvicorn company_news.query:app —port 8013 Access the exposed endpoint at http://localhost:8013/ and you will retrieve the inputs scheme defined above with named form elements texts, start, and end. This time we will skip registering the OpenAPI endpoint http://localhost:8013/openapi.json with koco start. Instead we immediately turn to Ray serve deployments.

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15. Test with Ray serve

Run the deployment, this time with the Ray fast_app object. Ensure you Ray cluster is up and running, i.e. with ray status. serve run company_news.query:fast_app Ray reports available routes at http://localhost:8000/-/routes. Verify the routes are properly published at http://localhost:8000/-/routes and retrieve the schema this time at http://localhost:8000/. Again we will skip koco serve until we have a proper deployment.

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16. Deploy with Ray serve

Deploy with Ray serve and run koco start to register your service with Kodosumi. serve deploy company_news.query:fast_app koco start —register http://localhost:8000/-/routes Now launch the admin panel at http://localhost:3370 and run a test from http://localhost:3370/inputs/-/localhost/8000/-/. Retrieve the inputs scheme from /-/localhost/8000/-/, and test the service at /inputs/-/localhost/8000/-/. Revisit the raw event stream with a given Flow Identifier (fid) at http://localhost:3370/outputs/stream/{fid}. Overall you will find the following events in the event stream of the news search agent:
  • status - execution status transitions from starting through running to finished
  • meta - service meta data with OpenAPI declarations among others
  • inputs - inputs parameters
  • result - intermediate results of the service as a data model, dict or list dump
  • stdout - captured prints and writes to stdout
  • final - the final response of the service as a data model, dict or list dump
  • eof - end-of-stream message
See Lifecycle and Events for further details. Use for example curl to POST a service requests with the panel API after successful authentication: 
curl -b cookie -c cookie -X POST -d '{"name": "admin", "password": "admin"}' http://localhost:3370/api/login
curl -b cookie -c cookie -X POST -d '{"texts": "audi\nbmw", "start": "2025-01-01", "end": "2025-01-31"}' http://localhost:3370/-/localhost/8000/-/
The response returns the Flow Identifier (fid). 
{
    "result": "...",
    "elements": ["..."]
}
Where to get from here?