# Rosetta

Package rosetta implements the rosetta API for the current cosmos sdk release series.

# Extension

There are two ways in which you can customize and extend the implementation with your custom settings.

# Message extension

In order to make an sdk.Msg understandable by rosetta the only thing which is required is adding the methods to your message that satisfy the rosetta.Msg interface. Examples on how to do so can be found in the staking types such as MsgDelegate, or in bank types such as MsgSend.

# Client interface override

In case more customization is required, it's possible to embed the Client type and override the methods which require customizations.

Example:

Copy package custom_client import ( "context" "github.com/coinbase/rosetta-sdk-go/types" "github.com/cosmos/cosmos-sdk/server/rosetta/lib" ) // CustomClient embeds the standard cosmos client // which means that it implements the cosmos-rosetta-gateway Client // interface while at the same time allowing to customize certain methods type CustomClient struct { *rosetta.Client } func (c *CustomClient) ConstructionPayload(_ context.Context, request *types.ConstructionPayloadsRequest) (resp *types.ConstructionPayloadsResponse, err error) { // provide custom signature bytes panic("implement me") }

# Error extension

Since rosetta requires to provide 'returned' errors to network options. In order to declare a new rosetta error, we use the errors package in cosmos-rosetta-gateway.

Example:

Copy package custom_errors import crgerrs "github.com/cosmos/cosmos-sdk/server/rosetta/lib/errors" var customErrRetriable = true var CustomError = crgerrs.RegisterError(100, "custom message", customErrRetriable, "description")

Note: errors must be registered before cosmos-rosetta-gateway's Server.Start method is called. Otherwise the registration will be ignored. Errors with same code will be ignored too.

# Integration in app.go

To integrate rosetta as a command in your application, in app.go, in your root command simply use the server.RosettaCommand method.

Example:

Copy package app import ( "github.com/cosmos/cosmos-sdk/server" "github.com/spf13/cobra" ) func buildAppCommand(rootCmd *cobra.Command) { // more app.go init stuff // ... // add rosetta command rootCmd.AddCommand(server.RosettaCommand(encodingConfig.InterfaceRegistry, encodingConfig.Marshaler)) }

A full implementation example can be found in simapp package.

NOTE: when using a customized client, the command cannot be used as the constructors required may differ, so it's required to create a new one. We intend to provide a way to init a customized client without writing extra code in the future.