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How to book a table at a restaurant using agents
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How to book a table at a restaurant using agents

Introduction

In this guide, we want to show how to set up the code to create a restaurant booking service with two Agents: a restaurant with tables available, and a user requesting table availability.

We also want to define 2 specific protocols, one for table querying (i.e., Table querying protocol) and one for table booking (i.e., Table booking protocol). Then we will need to define two agents scripts, restaurant and user, which will make use of the protocols to query and book a table.

Walk-through

  1. First of all, we need to navigate towards the directory you created for your project and create a folder for this task: mkdir booking_demo.

  2. Inside this folder we will create another folder for our protocols: mkdir protocols.

  3. After having defined our protocols, we will create 2 scripts, one for our restaurant and the other one for user agents. These agents will make use of the protocols to query, check, confirm and book an available table at the restaurant.

We can start by writing the code for our 2 protocols.

Protocols

Table querying protocol

Let's start by defining the protocol for querying availability of tables at the restaurant:

  1. First of all, we need to navigate towards the protocols folder: cd protocols

  2. Let's then create a Python script and name it by running: touch query.py

  3. In the text editor application, we proceed and define the table querying protocol.

  4. We now need to import necessary classes and define the message data models. Then, create an instance of the Protocol class and name it query_proto:

    from typing import List
 
from uagents import Context, Model, Protocol
 
class TableStatus(Model):
   seats: int
   time_start: int
   time_end: int
 
class QueryTableRequest(Model):
   guests: int
   time_start: int
   duration: int
 
class QueryTableResponse(Model):
   tables: List[int]
 
class GetTotalQueries(Model):
   pass
 
class TotalQueries(Model):
   total_queries: int
 
query_proto = Protocol()
    • TableStatus: this represents the status of a table and includes the attributes number of seats, start time, and end time.
    • QueryTableRequest: this is used for querying table availability. It includes information about the number of guests, start time, and duration of the table request.
    • QueryTableResponse: this contains the response to the query table availability. It includes a list of table numbers that are available based on query parameters.
    • GetTotalQueries: this is used to request the total number of queries made to the system.
    • TotalQueries: this contains the response to the total queries request, including the count of total queries made to the system.

  5. Let's then define the message handlers for the query_proto protocol:

    @query_proto.on_message(model=QueryTableRequest, replies=QueryTableResponse)
async def handle_query_request(ctx: Context, sender: str, msg: QueryTableRequest):
    tables = {
        int(num): TableStatus(**status)
        for (
            num,
            status,
        ) in ctx.storage._data.items()
        if isinstance(num, int)
    }
 
    available_tables = []
    for number, status in tables.items():
        if (
            status.seats >= msg.guests
            and status.time_start <= msg.time_start
            and status.time_end >= msg.time_start + msg.duration
        ):
            available_tables.append(int(number))
 
    ctx.logger.info(f"Query: {msg}. Available tables: {available_tables}.")
 
    await ctx.send(sender, QueryTableResponse(tables=available_tables))
 
    total_queries = int(ctx.storage.get("total_queries") or 0)
    ctx.storage.set("total_queries", total_queries + 1)
 
@query_proto.on_query(model=GetTotalQueries, replies=TotalQueries)
async def handle_get_total_queries(ctx: Context, sender: str, _msg: GetTotalQueries):
    total_queries = int(ctx.storage.get("total_queries") or 0)
    await ctx.send(sender, TotalQueries(total_queries=total_queries))

    • handle_query_request(): this message handler function is defined using the .on_message() decorator. It handles the QueryTableRequest messages and replies with a QueryTableResponse message. The handler processes the table availability query based on the provided parameters, checks the table statuses stored in the agent's storage, and sends the available table numbers as a response to the querying agent. Additionally, the handler tracks the total number of queries made and increments the count in storage.

    • handle_get_total_queries(): this message handler function is defined using the .on_query() decorator. It handles the GetTotalQueries query and replies with a TotalQueries message containing the total number of queries made to the system. The handler retrieves the total query count from the agent's storage and responds with the count.

  6. Save the script.

The overall script should look as follows:

query.py
from typing import List
 
from uagents import Context, Model, Protocol
 
class TableStatus(Model):
    seats: int
    time_start: int
    time_end: int
 
class QueryTableRequest(Model):
    guests: int
    time_start: int
    duration: int
 
class QueryTableResponse(Model):
    tables: List[int]
 
class GetTotalQueries(Model):
    pass
 
class TotalQueries(Model):
    total_queries: int
query_proto = Protocol()
 
@query_proto.on_message(model=QueryTableRequest, replies=QueryTableResponse)
async def handle_query_request(ctx: Context, sender: str, msg: QueryTableRequest):
    tables = {
        int(num): TableStatus(**status)
        for (
            num,
            status,
        ) in ctx.storage._data.items()
        if isinstance(num, int)
    }
    available_tables = []
    for number, status in tables.items():
        if (
            status.seats >= msg.guests
            and status.time_start <= msg.time_start
            and status.time_end >= msg.time_start + msg.duration
        ):
            available_tables.append(int(number))
    ctx.logger.info(f"Query: {msg}. Available tables: {available_tables}.")
    await ctx.send(sender, QueryTableResponse(tables=available_tables))
    total_queries = int(ctx.storage.get("total_queries") or 0)
    ctx.storage.set("total_queries", total_queries + 1)
 
@query_proto.on_query(model=GetTotalQueries, replies=TotalQueries)
async def handle_get_total_queries(ctx: Context, sender: str, _msg: GetTotalQueries):
    total_queries = int(ctx.storage.get("total_queries") or 0)
    await ctx.send(sender, TotalQueries(total_queries=total_queries))

Table booking protocol

We can now proceed by writing the booking protocol script for booking the table at the restaurant.

  1. First of all, navigate towards the protocols folder: cd protocols

  2. In here, let's create a Python script and name it by running: touch book.py

  3. In the text editor application, we can proceed to define the table booking protocol. We need to import the necessary classes and define the message data models. In this case, the booking protocol consists of two message models: BookTableRequest and BookTableResponse. Then create an instance of the Protocol class and name it book_proto:

    from uagents import Context, Model, Protocol
 
from .query import TableStatus
 
class BookTableRequest(Model):
    table_number: int
    time_start: int
    duration: int
 
class BookTableResponse(Model):
    success: bool
 
book_proto = Protocol()
    • BookTableRequest: this represents the request to book a table. It includes attributes: table_number to be booked, time_start of the booking, and the duration of the booking.
    • BookTableResponse: this contains the response to the table booking request. It includes a boolean attribute success, indicating whether the booking was successful or not.

  4. Let's now define a message handler function:

    @book_proto.on_message(model=BookTableRequest, replies=BookTableResponse)
async def handle_book_request(ctx: Context, sender: str, msg: BookTableRequest):
    tables = {
        int(num): TableStatus(**status)
        for (
            num,
            status,
        ) in ctx.storage._data.items()
        if isinstance(num, int)
    }
    table = tables[msg.table_number]
 
    if (
        table.time_start <= msg.time_start
        and table.time_end >= msg.time_start + msg.duration
    ):
        success = True
        table.time_start = msg.time_start + msg.duration
        ctx.storage.set(msg.table_number, table.dict())
    else:
        success = False
 
    # send the response
    await ctx.send(sender, BookTableResponse(success=success))

    The handle_book_request() handler first retrieves table statuses from the agent's storage and converts them into a dictionary with integer keys (table numbers) and TableStatus values. The TableStatus class is imported from the query module. Next, the handler gets the table associated with the requested table_number from the tables dictionary. The handler checks if the requested time_start falls within the availability period of the table. If the table is available for the requested booking duration, the handler sets success to True, updates the table's time_start to reflect the end of the booking, and saves the updated table information in the agent's storage using ctx.storage.set(). If the table is not available for the requested booking, the handler sets success to False.

    The handler sends a BookTableResponse message back to the sender with the success status of the booking using await ctx.send() method.

  5. Save the script.

The overall script should look as follows:

book.py
from uagents import Context, Model, Protocol
from .query import TableStatus
 
class BookTableRequest(Model):
    table_number: int
    time_start: int
    duration: int
 
class BookTableResponse(Model):
    success: bool
 
book_proto = Protocol()
@book_proto.on_message(model=BookTableRequest, replies=BookTableResponse)
async def handle_book_request(ctx: Context, sender: str, msg: BookTableRequest):
    tables = {
        int(num): TableStatus(**status)
        for (
            num,
            status,
        ) in ctx.storage._data.items()
        if isinstance(num, int)
    }
    table = tables[msg.table_number]
    if (
        table.time_start <= msg.time_start
        and table.time_end >= msg.time_start + msg.duration
    ):
        success = True
        table.time_start = msg.time_start + msg.duration
        ctx.storage.set(msg.table_number, table.dict())
    else:
        success = False
    # send the response
    await ctx.send(sender, BookTableResponse(success=success))

Restaurant Agent

We are now ready to define our restaurant agent.

  1. Let's now create a Python script in booking_demo folder, and name it by running: touch restaurant.py

  2. We then need to import the necessary classes from the uagents library and the two protocols we previously defined:

    from uagents import Agent
from uagents.setup import fund_agent_if_low
 
restaurant = Agent(
    name="restaurant",
    port=8001,
    seed="restaurant secret phrase",
    endpoint=["http://127.0.0.1:8001/submit"],
)
 
fund_agent_if_low(restaurant.wallet.address())

  3. Let's build the restaurant agent from above protocols and set the table availability information:

    from protocols.book import book_proto
from protocols.query import query_proto, TableStatus
 
# build the restaurant agent from stock protocols
restaurant.include(query_proto)
restaurant.include(book_proto)
 
TABLES = {
    1: TableStatus(seats=2, time_start=16, time_end=22),
    2: TableStatus(seats=4, time_start=19, time_end=21),
    3: TableStatus(seats=4, time_start=17, time_end=19),
}

  4. We would then need to store the TABLES information in the restaurant agent and run it:

    for (number, status) in TABLES.items():
    restaurant._storage.set(number, status.dict())
 
if __name__ == "__main__":
    restaurant.run()

  5. Save the script.

The restaurant agent is now online and ready to receive messages.

The overall script should look as follows:

restaurant.py
from uagents import Agent, Context
from uagents.setup import fund_agent_if_low
from protocols.book import book_proto
from protocols.query import query_proto, TableStatus
 
restaurant = Agent(
    name="restaurant",
    port=8001,
    seed="restaurant secret phrase",
    endpoint=["http://127.0.0.1:8001/submit"],
)
 
fund_agent_if_low(restaurant.wallet.address())
 
# build the restaurant agent from stock protocols
restaurant.include(query_proto)
restaurant.include(book_proto)
TABLES = {
    1: TableStatus(seats=2, time_start=16, time_end=22),
    2: TableStatus(seats=4, time_start=19, time_end=21),
    3: TableStatus(seats=4, time_start=17, time_end=19),
}
 
# set the table availability information in the restaurant protocols
for (number, status) in TABLES.items():
    restaurant._storage.set(number, status.dict())
 
if __name__ == "__main__":
    restaurant.run()

User uAgent

We can finally define the script for our user agent querying and booking a table at the restaurant.

  1. First of all, let's create a Python script in booking_demo folder, and name it: touch user.py

  2. We then need to import necessary classes from the uagents library and the two protocols defined above. We also need the restaurant agent's address to be able to communicate with it:

    from uagents import Agent, Context
from uagents.setup import fund_agent_if_low
from protocols.book import BookTableRequest, BookTableResponse
from protocols.query import (
    QueryTableRequest,
    QueryTableResponse,
)
 
RESTAURANT_ADDRESS = "agent1qw50wcs4nd723ya9j8mwxglnhs2kzzhh0et0yl34vr75hualsyqvqdzl990"
 
user = Agent(
    name="user",
    port=8000,
    seed="user secret phrase",
    endpoint=["http://127.0.0.1:8000/submit"],
)
 
fund_agent_if_low(user.wallet.address())

  3. Let's then create the table query to generate the QueryTableRequest using the restaurant address. If the request has not been completed before, we send the request to the restaurant agent. Then create an interval() function which performs a table query request on a defined period to the restaurant agent, to query the availability of a table given the table_query parameters:

    table_query = QueryTableRequest(
    guests=3,
    time_start=19,
    duration=2,
)
 
@user.on_interval(period=3.0, messages=QueryTableRequest)
async def interval(ctx: Context):
    completed = ctx.storage.get("completed")
 
    if not completed:
        await ctx.send(RESTAURANT_ADDRESS, table_query)

  4. Define the message handler function for incoming QueryTableResponse messages from the restaurant agent:

    @user.on_message(QueryTableResponse, replies={BookTableRequest})
async def handle_query_response(ctx: Context, sender: str, msg: QueryTableResponse):
    if len(msg.tables) > 0:
        ctx.logger.info("There is a free table, attempting to book one now")
        table_number = msg.tables[0]
        request = BookTableRequest(
            table_number=table_number,
            time_start=table_query.time_start,
            duration=table_query.duration,
        )
        await ctx.send(sender, request)
    else:
        ctx.logger.info("No free tables - nothing more to do")
        ctx.storage.set("completed", True)

    This function activates when a message is received back from the restaurant agent. handle_query_response() function will evaluate if there is a table available, and if so, it responds with a BookTableRequest to complete the reservation.

  5. Let's then define a function which will handle messages from the restaurant agent on whether the reservation was successful or not:

    @user.on_message(BookTableResponse, replies=set())
async def handle_book_response(ctx: Context, _sender: str, msg: BookTableResponse):
    if msg.success:
        ctx.logger.info("Table reservation was successful")
 
    else:
        ctx.logger.info("Table reservation was UNSUCCESSFUL")
 
    ctx.storage.set("completed", True)
 
if __name__ == "__main__":
    user.run()

  6. Save the script.

The overall script should look as follows:

user.py
from protocols.book import BookTableRequest, BookTableResponse
from protocols.query import (
    QueryTableRequest,
    QueryTableResponse,
)
from uagents import Agent, Context
from uagents.setup import fund_agent_if_low
 
RESTAURANT_ADDRESS = "agent1qw50wcs4nd723ya9j8mwxglnhs2kzzhh0et0yl34vr75hualsyqvqdzl990"
 
user = Agent(
    name="user",
    port=8000,
    seed="user secret phrase",
    endpoint=["http://127.0.0.1:8000/submit"],
)
 
fund_agent_if_low(user.wallet.address())
 
table_query = QueryTableRequest(
    guests=3,
    time_start=19,
    duration=2,
)
 
# This on_interval agent function performs a request on a defined period
@user.on_interval(period=3.0, messages=QueryTableRequest)
async def interval(ctx: Context):
    completed = ctx.storage.get("completed")
 
    if not completed:
        await ctx.send(RESTAURANT_ADDRESS, table_query)
 
@user.on_message(QueryTableResponse, replies={BookTableRequest})
async def handle_query_response(ctx: Context, sender: str, msg: QueryTableResponse):
    if len(msg.tables) > 0:
        ctx.logger.info("There is a free table, attempting to book one now")
 
        table_number = msg.tables[0]
 
        request = BookTableRequest(
            table_number=table_number,
            time_start=table_query.time_start,
            duration=table_query.duration,
        )
 
        await ctx.send(sender, request)
 
    else:
 
        ctx.logger.info("No free tables - nothing more to do")
        ctx.storage.set("completed", True)
 
@user.on_message(BookTableResponse, replies=set())
async def handle_book_response(ctx: Context, _sender: str, msg: BookTableResponse):
    if msg.success:
        ctx.logger.info("Table reservation was successful")
 
    else:
        ctx.logger.info("Table reservation was UNSUCCESSFUL")
 
    ctx.storage.set("completed", True)
 
if __name__ == "__main__":
    user.run()

Run the scripts

Run the restaurant agent and then the user agent from different terminals:

  • Terminal 1: python restaurant.py

  • Terminal 2: python user.py

The output should be as follows, depending on the terminal:

  • Restaurant

    [restaurant]: Query: guests=3 time_start=19 duration=2. Available tables: [2].

  • User

    [ user]: There is a free table, attempting to book one now
[ user]: Table reservation was successful

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