Exception Interface

The Exception Interface specifies an exception or error that occurred in a program.

An event may contain one or more exceptions in an attribute named exception.

The exception attribute should be an object with the attribute values containing a list of one or more values that are objects in the format described below.

Multiple values represent chained exceptions and should be sorted oldest to newest. For example, consider this Python code snippet:

try:
    raise Exception
except Exception as e:
    raise ValueError from e

Exception would be described first in the values list, followed by a description of ValueError.

Attributes

type

The type of exception, e.g. ValueError.

value

The value of the exception (a string).

module

The optional module, or package which the exception type lives in.

thread_id

An optional value which refers to a thread in the Threads Interface.

mechanism

An optional object describing the mechanism that created this exception.

stacktrace

An optional stack trace object corresponding to the Stack Trace Interface.

Exception Mechanism

The exception mechanism is an optional field residing in the Exception Interface. It carries additional information about the way the exception was created on the target system. This includes general exception values obtained from the operating system or runtime APIs, as well as mechanism-specific values.

Attributes

type

Required unique identifier of this mechanism determining rendering and processing of the mechanism data.

description

Optional human-readable description of the error mechanism and a possible hint on how to solve this error.

help_link

Optional fully qualified URL to an online help resource, possibly interpolated with error parameters.

handled

Optional flag indicating whether the user has handled the exception (for example, via try ... catch).

synthetic

An optional flag indicating that this error is synthetic. Synthetic errors are errors that carry little meaning by themselves. This may be because they are created at a central place (like a crash handler), and are all called the same: Error, Segfault etc. When the flag is set, Sentry will then try to use other information (top in-app frame function) rather than exception type and value in the UI for the primary event display. This flag should be set for all "segfaults" for instance as every single error group would look very similar otherwise.

meta

Optional information from the operating system or runtime on the exception mechanism (see meta information).

data

Arbitrary extra data that might help the user understand the error thrown by this mechanism.

Meta information

The mechanism metadata usually carries error codes reported by the runtime or operating system, along with a platform-dependent interpretation of these codes. SDKs can safely omit code names and descriptions for well-known error codes, as it will be filled out by Sentry. For proprietary or vendor-specific error codes, adding these values will give additional information to the user.

The meta key may contain one or more of the following attributes:

signal

Information on the POSIX signal. On Apple systems, signals also carry a code in addition to the signal number describing the signal in more detail. On Linux, this code does not exist.

number

The POSIX signal number.

code

Optional Apple signal code.

name

Optional name of the signal based on the signal number.

code_name

Optional name of the signal code.

mach_exception

A Mach Exception on Apple systems comprising a code triple and optional descriptions.

exception

Required numeric exception number.

code

Required numeric exception code.

subcode

Required numeric exception subcode.

name

Optional name of the exception constant in iOS / macOS.

ns_error

An NSError on Apple systems comprising of domain and code.

code

Required numeric error code.

domain

Required domain of the NSError as string.

errno

Error codes set by Linux system calls and some library functions as specified in ISO C99, POSIX.1-2001, and POSIX.1-2008. See errno(3) for more information.

number

The error number

name

Optional name of the error

Examples

The following examples illustrate multiple ways to send exceptions. Each example contains the exception part of the event payload and omits other attributes for simplicity.

A single exception:

{
  "exception": {
    "values": [
      {
        "type": "ValueError",
        "value": "my exception value",
        "module": "__builtins__",
        "stacktrace": {}
      }
    ]
  }
}

Chained exceptions:

{
  "exception": {
    "values": [
      {
        "type": "Exception",
        "value": "initial exception",
        "module": "__builtins__"
      },
      {
        "type": "ValueError",
        "value": "chained exception",
        "module": "__builtins__"
      }
    ]
  }
}

iOS native mach exception with mechanism:

{
  "exception": {
    "values": [
      {
        "type": "EXC_BAD_ACCESS",
        "value": "Attempted to dereference a null pointer",
        "mechanism": {
          "type": "mach",
          "handled": false,
          "data": {
            "relevant_address": "0x1"
          },
          "meta": {
            "signal": {
              "number": 10,
              "code": 0,
              "name": "SIGBUS",
              "code_name": "BUS_NOOP"
            },
            "mach_exception": {
              "code": 0,
              "subcode": 8,
              "exception": 1,
              "name": "EXC_BAD_ACCESS"
            }
          }
        }
      }
    ]
  }
}

JavaScript unhandled promise rejection:

{
  "exception": {
    "values": [
      {
        "type": "TypeError",
        "value": "Object [object Object] has no method 'foo'",
        "mechanism": {
          "type": "promise",
          "description": "This error originated either by throwing inside of an ...",
          "handled": false,
          "data": {
            "polyfill": "bluebird"
          }
        }
      }
    ]
  }
}

Generic unhandled crash:

{
  "exception": {
    "values": [
      {
        "type": "Error",
        "value": "An error occurred",
        "mechanism": {
          "type": "generic",
          "handled": false
        }
      }
    ]
  }
}