# Runtime

## Running Your Main Program with runMain

`runMain` helps you execute a main effect with built-in error handling, logging, and signal management. You can concentrate on your effect while `runMain` looks after finalizing resources, logging errors, and setting exit codes.

- **Exit Codes**
  If your effect fails or is interrupted, `runMain` assigns a suitable exit code (for example, `1` for errors and `0` for success).
- **Logs**
  By default, it records errors. This can be turned off if needed.
- **Interrupt Handling**
  If the application receives `SIGINT` (Ctrl+C) or a similar signal, `runMain` will interrupt the effect and still run any necessary teardown steps.
- **Teardown Logic**
  You can rely on the default teardown or define your own. The default sets an exit code of `1` for a non-interrupted failure.

### Usage Options

When calling `runMain`, pass in a configuration object with these fields (all optional):

- `disableErrorReporting`: If `true`, errors are not automatically logged.
- `teardown`: Provide a custom function for finalizing the program. If missing, the default sets exit code `1` for a non-interrupted failure.

**Example** (Running a Successful Program)

```ts
import { NodeRuntime } from "@effect/platform-node"
import { Effect } from "effect"

const success = Effect.succeed("Hello, World!")

NodeRuntime.runMain(success)
// No Output
```

**Example** (Running a Failing Program)

```ts
import { NodeRuntime } from "@effect/platform-node"
import { Effect } from "effect"

const failure = Effect.fail("Uh oh!")

NodeRuntime.runMain(failure)
/*
Output:
[12:43:07.186] ERROR (#0):
  Error: Uh oh!
*/
```

**Example** (Running a Failing Program Without Error Reporting)

```ts
import { NodeRuntime } from "@effect/platform-node"
import { Effect } from "effect"

const failure = Effect.fail("Uh oh!")

NodeRuntime.runMain(failure, { disableErrorReporting: true })
// No Output
```

**Example** (Running a Failing Program With Custom Teardown)

```ts
import { NodeRuntime } from "@effect/platform-node"
import { Effect } from "effect"

const failure = Effect.fail("Uh oh!")

NodeRuntime.runMain(failure, {
  teardown: function customTeardown(exit, onExit) {
    if (exit._tag === "Failure") {
      console.error("Program ended with an error.")
      onExit(1)
    } else {
      console.log("Program finished successfully.")
      onExit(0)
    }
  },
})
/*
Output:
[12:46:39.871] ERROR (#0):
  Error: Uh oh!
Program ended with an error.
*/
```