How to chain multiple errors together to create a trace of errors in Go?

In Go, you can chain multiple errors together to create a trace of errors using the github.com/pkg/errors package. This package provides functions to annotate errors with additional context and create stack traces.

To chain errors and create a trace, follow these steps:

1. Install the github.com/pkg/errors package:

   go get github.com/pkg/errors

2. Import the package in your Go file:

   import "github.com/pkg/errors"

3. Create a new error by wrapping an existing error with context using the errors.Wrap function:

   err := errors.Wrap(existingError, "additional context")

   The Wrap function adds the additional context message to the error and includes the existing error as the cause.

4. To extract the original error from the wrapped error, you can use the errors.Cause function:

   originalError := errors.Cause(wrappedError)

5. You can then chain multiple errors by wrapping each error with additional context:

   err2 := errors.Wrap(err1, "additional context2")

   Here, err2 becomes a wrapped error with err1 as the cause.

6. To print the full error trace, use the %+v formatting flag with the wrapped error:

   fmt.Printf("%+v\n", err2)

   The %+v flag prints the error message, the error stack trace, and the context added at each level.

By chaining errors and providing context at each level, you can create an error trace that provides valuable information for troubleshooting and debugging.