Nebulex.Error exception (Nebulex v3.1.0)

Raised, or returned in an {:error, _} tuple, when a command fails. For example, the adapter could not run it, it timed out, or a transaction was aborted.

Exception fields

See t/0.

Error reasons

The :reason field can be one of:

:timeout - the command timed out.
:transaction_aborted - a transaction failed and was aborted.
:event_listener_already_exists - another cache entry listener with the same ID is already registered.
:event_listener_error - a cache entry event listener failed while processing an event.
Exception.t/0 - the adapter raised an exception.
any/0 - the command failed with an adapter-specific error.

Summary

Types

reason()

Error reason type.

t()

The type for this exception struct.

Functions

format_error(reason, metadata)

Formats the error message. A custom formatter module (see the :module field) must define a function with the same name and arguments.

maybe_format_metadata(msg, metadata)

Formats the error metadata when not empty.

Types

reason()

@type reason() :: any()

Error reason type.

Usually an atom, a {atom, term} tuple, or an exception, but adapters may use any term.

t()

@type t() :: %Nebulex.Error{
  __exception__: term(),
  metadata: keyword(),
  module: module(),
  reason: reason()
}

The type for this exception struct.

This exception has the following public fields:

:reason - the error reason. It can be one of the Nebulex-specific reasons described in the "Error reasons" section in the module documentation.
:module - a custom error formatter module. When present, the message is built with module.format_error(reason, metadata), where metadata is the keyword list given to the exception. See format_error/2.
:metadata - the options given to the exception, minus :reason and :module. For example, raise Nebulex.Error, reason: :test, foo: :bar gives the metadata [foo: :bar].

Functions

format_error(reason, metadata)

@spec format_error(any(), keyword()) :: binary()

Formats the error message. A custom formatter module (see the :module field) must define a function with the same name and arguments.

Arguments

reason - the error reason.
metadata - a keyword with the metadata given to the exception.

For example, if an adapter returns:

wrap_error Nebulex.Error,
  reason: :my_reason,
  module: MyAdapter.Formatter,
  foo: :bar

the exception invokes:

MyAdapter.Formatter.format_error(:my_reason, foo: :bar)

maybe_format_metadata(msg, metadata)

@spec maybe_format_metadata(binary(), keyword()) :: binary()

Formats the error metadata when not empty.