> ## 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.

# Custom Errors Setup

> How to setup custom errors in your project

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

# Install the lytix SDK

<CodeGroup>
  ```sh Python
  pip3 install lytix-py
  ```

  ```sh Typescript
  npm install @lytix/client
  ```
</CodeGroup>

#### (Reccomended) Set you API key via the environment variable

```sh
export LX_API_KEY=<your-api-key-here>
```

#### Set your API key in the code

<CodeGroup>
  ```py Python
  from optimodel import LytixCreds

  LytixCreds.setAPIKey('<your-api-key-here>')
  ```

  ```ts Typescript
  import { LytixCred } from "@lytix/client";

  LytixCreds.setAPIKey("sk-1234");
  ```
</CodeGroup>

# Error Class

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

<CodeGroup>
  ```py Python
  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)
  ```

  ```ts Typescript
  import { LError, LLogger } from "@lytix/client";

  ...
  app.get("/test", async (req, res) => {
    const logger = new LLogger('testRoute');
    /**
     * Lets pretend an error happend
     */
    try {
      logger.info("Some process is starting");
      throw new LError("An unexpeted error", { env: "prod" });
    } catch (err) {
      logger.error("crazy unexpeted error with this user: 123", err);
      res.sendStatus(500);
      return;
    }

    /**
     * Magically if we ended here, we'd reply with a 200
     */
    res.send("Hello World");
  });
  ...
  ```
</CodeGroup>

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

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

# Error Increment

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

<CodeGroup>
  ```py Python
  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)
  ```

  ```ts Typescript
  import { LErrorIncrement, LLogger } from "@lytix/client";

  /**
   * An example background process
   */
  const backgroundProcess = async () => {
    const logger = new LLogger("backgroundProcessExample", { userId: "123" });
    try {
      logger.info("Background process started for user!");
      throw new Error("Unexpected error!");
    } catch (err) {
      /**
       * Just increment to get the logs as well as the error
       */
      logger.error(`Unexpected error happened`, err);
      LErrorIncrement("Unexpected error");
    }
  };
  ```
</CodeGroup>

# Examples

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