# wgc grpc-service generate

The `generate` command generates a protobuf definition and mapping file for a gRPC service from a GraphQL schema, which can be used to implement a gRPC service and can be used for the composition.

## Usage

```
wgc grpc-service generate [options] [service-name]
```

## Arguments

| Argument         | Description                                 | Default       |
|------------------|---------------------------------------------|---------------|
| `service-name`   | Name of the gRPC service                    | `service.v1`  |

## Options

| Option                                  | Description                                                                  | Default |
|-----------------------------------------|------------------------------------------------------------------------------|---------|
| `-i, --input <path-to-input>`          | The GraphQL schema file to generate a protobuf schema from                  | Required|
| `-o, --output <path-to-output>`        | The output directory for the protobuf schema                                 | `.`     |
| `-p, --package-name <name>`            | The name of the proto package                                                | `service.v1` |
| `-g, --go-package <name>`              | Adds an `option go_package` to the proto file                               | None    |

## Description

This command generates a protobuf definition for a gRPC service from a GraphQL schema.

## Examples

### Generate a protobuf definition for a gRPC service from a GraphQL schema

```
wgc grpc-service generate -i ./schema.graphql -o ./service MyService
```

### Define a custom package name

```
wgc grpc-service generate -i ./schema.graphql -o ./service MyService --package-name my.custom.package
```

### Define a custom go package name

```
wgc grpc-service generate -i ./schema.graphql -o ./service MyService --go-package github.com/wundergraph/cosmo/service/my-service
```

## Output

The command generates multiple files in the output directory:

- `service.proto`: The protobuf definition for the gRPC service
- `service.mapping.json`: The mapping file for the gRPC service
- `service.proto.lock.json`: The lock file for the protobuf definition

The generated protobuf definition can be used to implement a gRPC service in any language that supports protobuf. The mapping and the protobuf definition are needed for the composition part. See also: [gRPC Services](https://cosmo-docs.wundergraph.com/router/gRPC/grpc-services) · [GraphQL Support for gRPC Integration](https://cosmo-docs.wundergraph.com/router/gRPC/graphql-support)