55 lines
2.1 KiB
Markdown
55 lines
2.1 KiB
Markdown
<!--
|
|
order: 13
|
|
-->
|
|
|
|
# Errors
|
|
|
|
This document outlines the recommended usage and APIs for error handling in Cosmos SDK modules. {synopsis}
|
|
|
|
Modules are encouraged to define and register their own errors to provide better
|
|
context on failed message or handler execution. Typically, these errors should be
|
|
common or general errors which can be further wrapped to provide additional specific
|
|
execution context.
|
|
|
|
## Registration
|
|
|
|
Modules should define and register their custom errors in `x/{module}/types/errors.go`. Registration
|
|
of errors is handled via the `types/errors` package.
|
|
|
|
Example:
|
|
|
|
+++ https://github.com/cosmos/cosmos-sdk/blob/v0.38.1/x/distribution/types/errors.go#L1-L21
|
|
|
|
Each custom module error must provide the codespace, which is typically the module name
|
|
(e.g. "distribution") and is unique per module, and a uint32 code. Together, the codespace and code
|
|
provide a globally unique SDK error. Typically, the code is monotonically increasing but does not
|
|
necessarily have to be. The only restrictions on error codes are the following:
|
|
|
|
* Must be greater than one, as a code value of one is reserved for internal errors.
|
|
* Must be unique within the module.
|
|
|
|
Note, the SDK provides a core set of *common* errors. These errors are defined in `types/errors/errors.go`.
|
|
|
|
## Wrapping
|
|
|
|
The custom module errors can be returned as their concrete type as they already fulfill the `error`
|
|
interface. However, module errors can be wrapped to provide further context and meaning to failed
|
|
execution.
|
|
|
|
Example:
|
|
|
|
+++ https://github.com/cosmos/cosmos-sdk/blob/b2d48a9e815fe534a7faeec6ca2adb0874252b81/x/bank/keeper/keeper.go#L85-L122
|
|
|
|
Regardless if an error is wrapped or not, the SDK's `errors` package provides an API to determine if
|
|
an error is of a particular kind via `Is`.
|
|
|
|
## ABCI
|
|
|
|
If a module error is registered, the SDK `errors` package allows ABCI information to be extracted
|
|
through the `ABCIInfo` API. The package also provides `ResponseCheckTx` and `ResponseDeliverTx` as
|
|
auxiliary APIs to automatically get `CheckTx` and `DeliverTx` responses from an error.
|
|
|
|
## Next {hide}
|
|
|
|
Learn about [interfaces](../interfaces/interfaces-intro.md) {hide}
|