> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lytix.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Trace Capturing

> How to capture errors in your code

<Info>
  **Prerequisite** Please see [here](/api-key-setup) to get and set your API Key environment variable.
</Info>

Install the Lytix pip package

```bash
pip3 install lytix-py
```

*Make sure to set your API key e.g. `export LX_API_KEY=...`*

#### Error Class

You can now just replace all your `raise Exception` calls with `raise LError`. For example:

```py
from lytix_py import LError, LLogger

async def backgroundProcess():
    logger = LLogger("background-logger", {"userId": '124'})
    logger.info("Some process is starting")
    raise LError("An unexpected error")

async def main(): 
    await backgroundProcess()


if __name__ == "__main__":
    logger  = LLogger("main")
    logger.runInAsyncContext(main)
```

The error, along with the last 20 log lines will automatically get pushed to the Lytix platform [here](https://lab.lytix.co/home/errors)

![title](https://mintlify.s3-us-west-1.amazonaws.com/lytix/images/node-quickstart/LErrorExample.png)

#### Error Increment

You can also send an error along with related logs without throwing an error by using the `increment` method.

```py
from lytix_py.LError import LErrorIncrement, LLogger

async def backgroundProcess():
    logger = LLogger("background-logger", {"userId": '124'})
    logger.info("Some context on the user here")
    try:
        raise Exception("LIncrement error happened")
    except Exception as e:
        logger.error("LIncrement error happened")
        LErrorIncrement("Some error")
                        
async def main(): 
    logger = LLogger("main-logger")
    logger.info("Starting in our main LIncrement process")
    await backgroundProcess()


if __name__ == "__main__":
    logger  = LLogger("main")
    logger.runInAsyncContext(main)
```

#### Fast API Integration

Lytix also supports capturing errors in FastAPI. To get started first hook up our Lytix middleware:

```py
from lytix_py.FastAPIMiddleware.LytixMiddleware import LytixMiddleware
from fastapi import FastAPI

...
app = FastAPI()

app.add_middleware(LytixMiddleware)
...
```

Now you can throw errors in your FastAPI routes or subcalls as follows:

```py

# main.py
@app.get("/")
async def read_root():
    logger = LLogger("read-root")
    logger.info('In the main view here...')
    await backgroundFastAPIProcess()
    return {"Hello": "World"}

# backgroundProcess.py
async def backgroundFastAPIProcess(): 
    logger = LLogger("background-fast-api-process")
    logger.info("In the background here")

    """
    All the logs associated with this request will get sent to lytix
    """
    raise LError("Some error")
```

#### Examples

To see all examples please check the Github repo [here](https://github.com/Lytix-Labs/lytix-py/tree/master/example)