# API

Piston exposes an API for managing packages and executing user-defined code.

The API is broken in to 2 main sections - packages and jobs.

The API is exposed from the container, by default on port 2000, at `/api/v2/`.

All inputs are validated, and if an error occurs, a 4xx or 5xx status code is returned.
In this case, a JSON payload is sent back containing the error message as `message`

## Runtimes

### `GET /api/v2/runtimes`

Returns a list of available languages, including the version, runtime and aliases.

#### Response

- `[].language`: Name of the language
- `[].version`: Version of the runtime
- `[].aliases`: List of alternative names that can be used for the language
- `[].runtime` (_optional_): Name of the runtime used to run the langage, only provided if alternative runtimes exist for the language

#### Example

```
GET /api/v2/runtimes
```

```json
HTTP/1.1 200 OK
Content-Type: application/json

[
  {
    "language": "bash",
    "version": "5.1.0",
    "aliases": ["sh"]
  },
  {
    "language": "javascript",
    "version": "15.10.0",
    "aliases": ["node-javascript", "node-js", "javascript", "js"],
    "runtime": "node"
  }
]
```

## Execute

### `POST /api/v2/execute`

Runs the given code, using the given runtime and arguments, returning the result.

#### Request

- `language`: Name or alias of a language listed in [runtimes](#runtimes)
- `version`: SemVer version selector of a language listed in [runtimes](#runtimes)
- `files`: An array of files which should be uploaded into the job context
- `files[].name` (_optional_): Name of file to be written, if none a random name is picked
- `files[].content`: Content of file to be written
- `stdin` (_optional_): Text to pass into stdin of the program. Defaults to blank string.
- `args` (_optional_): Arguments to pass to the program. Defaults to none
- `run_timeout` (_optional_): The maximum allowed time in milliseconds for the compile stage to finish before bailing out. Must be a number, less than or equal to the configured maximum timeout.
- `compile_timeout` (_optional_): The maximum allowed time in milliseconds for the run stage to finish before bailing out. Must be a number, less than or equal to the configured maximum timeout. Defaults to maximum.
- `compile_memory_limit` (_optional_): The maximum amount of memory the compile stage is allowed to use in bytes. Must be a number, less than or equal to the configured maximum. Defaults to maximum, or `-1` (no limit) if none is configured.
- `run_memory_limit` (_optional_): The maximum amount of memory the run stage is allowed to use in bytes. Must be a number, less than or equal to the configured maximum. Defaults to maximum, or `-1` (no limit) if none is configured.

#### Response

- `language`: Name (not alias) of the runtime used
- `version`: Version of the used runtime
- `run`: Results from the run stage
- `run.stdout`: stdout from run stage process
- `run.stderr`: stderr from run stage process
- `run.output`: stdout and stderr combined in order of data from run stage process
- `run.code`: Exit code from run process, or null if signal is not null
- `run.signal`: Signal from run process, or null if code is not null
- `compile` (_optional_): Results from the compile stage, only provided if the runtime has a compile stage
- `compile.stdout`: stdout from compile stage process
- `compile.stderr`: stderr from compile stage process
- `compile.output`: stdout and stderr combined in order of data from compile stage process
- `compile.code`: Exit code from compile process, or null if signal is not null
- `compile.signal`: Signal from compile process, or null if code is not null

#### Example

```json
POST /api/v2/execute
Content-Type: application/json

{
  "language": "js",
  "version": "15.10.0",
  "files": [
    {
      "name": "my_cool_code.js",
      "content": "console.log(process.argv)"
    }
  ],
  "stdin": "",
  "args": ["1", "2", "3"],
  "compile_timeout": 10000,
  "run_timeout": 3000,
  "compile_memory_limit": -1,
  "run_memory_limit": -1
}
```

```json
HTTP/1.1 200 OK
Content-Type: application/json

{
  "run": {
    "stdout": "[\n  '/piston/packages/node/15.10.0/bin/node',\n  '/piston/jobs/e87afa0d-6c2a-40b8-a824-ffb9c5c6cb64/my_cool_code.js',\n  '1',\n  '2',\n  '3'\n]\n",
    "stderr": "",
    "code": 0,
    "signal": null,
    "output": "[\n  '/piston/packages/node/15.10.0/bin/node',\n  '/piston/jobs/e87afa0d-6c2a-40b8-a824-ffb9c5c6cb64/my_cool_code.js',\n  '1',\n  '2',\n  '3'\n]\n"
  },
  "language": "javascript",
  "version": "15.10.0"
}
```

## Packages

### `GET /api/v2/packages`

Returns a list of all possible packages, and whether their installation status.

#### Response

- `[].language`: Name of the contained runtime
- `[].language_version`: Version of the contained runtime
- `[].installed`: Status on the package being installed

#### Example

```
GET /api/v2/packages
```

```json
HTTP/1.1 200 OK
Content-Type: application/json

[
  {
    "language": "node",
    "language_version": "15.10.0",
    "installed": true
  },
  {
    "language": "bash",
    "language_version": "5.1.0",
    "installed": true
  }
]
```

### `POST /api/v2/packages`

Install the given package.

#### Request

- `language`: Name of package from [package list](#get-apiv2packages)
- `version`: SemVer version selector for package from [package list](#get-apiv2packages)

#### Response

- `language`: Name of package installed
- `version`: Version of package installed

#### Example

```json
POST /api/v2/packages
Content-Type: application/json

{
  "language": "bash",
  "version": "5.x"
}
```

```json
HTTP/1.1 200 OK
Content-Type: application/json

{
  "language": "bash",
  "version": "5.1.0"
}
```

### `DELETE /api/v2/packages`

Uninstall the given package.

#### Request

- `language`: Name of package from [package list](#get-apiv2packages)
- `version`: SemVer version selector for package from [package list](#get-apiv2packages)

#### Response

- `language`: Name of package uninstalled
- `version`: Version of package uninstalled

#### Example

```json
DELETE /api/v2/packages
Content-Type: application/json

{
  "language": "bash",
  "version": "5.x"
}
```

```json
HTTP/1.1 200 OK
Content-Type: application/json

{
  "language": "bash",
  "version": "5.1.0"
}
```