pip_services3_commons.errors package

Submodules

Module contents

pip_services3_commons.errors.__init__

Portable and localizable Exceptions classes. Each Exception, in addition to a description and stack trace has a unique string code, details array (which can be used for creating localized strings).

Way to use: - An existing error class can be used. - A child class that extends ApplicationException can we written. - A error can be wrapped around (into?) an existing application error.

Exceptions are serializable. The error classes themselves are not serializable, but they can be converted to ErrorDescriptions, which are serializable in one language, transferred to the receiving side, and deserialized in another language. After deserialization, the initial error class can be restored.

Additionally: when transferring an error from one language to another, the error type that is closest to the initial error type is chosen from the exceptions available in the target language.

copyright

Conceptual Vision Consulting LLC 2018-2019, see AUTHORS for more details.

license

MIT, see LICENSE for more details.

exception pip_services3_commons.errors.ApplicationException(category: str = 'Unknown', correlation_id: Optional[str, None] = None, code: str = 'UNKNOWN', message: str = 'Unknown error')

Bases: Exception

Defines a base class to defive various application exceptions.

Most languages have own definition of base error (error) types. However, this class is implemented symmetrically in all languages supported by PipServices toolkit. It allows to create portable implementations and support proper error propagation in microservices calls.

Error propagation means that when microservice implemented in one language calls microservice(s) implemented in a different language(s), errors are returned throught the entire call chain and restored in their original (or close) type.

Since number of potential error types is endless, PipServices toolkit supports only 12 standard categories of exceptions defined in ErrorCategory. This ApplicationException class acts as a basis for all obj 12 standard error types.

Most exceptions have just free-form message that describes occured error. That may not be sufficient to create meaninful error descriptions. The ApplicationException class proposes an extended error definition that has more standard fields: - message: is a human-readable error description - category: one of 12 standard error categories of errors - status: numeric HTTP status code for REST invocations - code: a unique error code, usually defined as “MY_ERROR_CODE” - correlation_id: a unique transaction id to trace execution through a call chain - details: map with error parameters that can help to recreate meaningful error description in obj languages - stack_trace: a stack trace - cause: original error that is wrapped by this error

ApplicationException class is not serializable. To pass errors through the wire it is converted into ErrorDescription <pip_services3_commons.errors.ErrorDescription.ErrorDescription>` object and restored on receiving end into identical error type.

get_cause_string()str

Gets original error wrapped by this error as a string message.

Returns

an original error message.

get_stack_trace_string() → Optional[str, None]

Gets a stack trace where this error occured.

Returns

a stack trace as a string.

set_cause_string(value: str)

Sets original error wrapped by this error as a string message.

Parameters

value – an original error message.

set_stack_trace_string(value: str)

Sets a stack trace where this error occured.

Parameters

value – a stack trace as a string

to_json()
with_cause(cause: Exception)pip_services3_commons.errors.ApplicationException.ApplicationException

Sets a original error wrapped by this error

This method returns reference to this error to implement Builder pattern to chain additional calls.

Parameters

cause – original error object

Returns

this error object

with_code(code: str)pip_services3_commons.errors.ApplicationException.ApplicationException

Sets a unique error code. This method returns reference to this error to implement Builder pattern to chain additional calls.

Parameters

code – a unique error code

Returns

this error object

with_correlation_id(correlation_id: Optional[str, None])pip_services3_commons.errors.ApplicationException.ApplicationException

Sets a correlation id which can be used to trace this error through a call chain.

This method returns reference to this error to implement Builder pattern to chain additional calls.

Parameters

correlation_id – a unique transaction id to trace error through call chain

Returns

this error object

with_details(key: str, value: Any)pip_services3_commons.errors.ApplicationException.ApplicationException

Sets a parameter for additional error details. This details can be used to restore error description in obj languages.

This method returns reference to this error to implement Builder pattern to chain additional calls.

Parameters
  • key – a details parameter name

  • value – a details parameter name

Returns

this error object

with_stack_trace(stack_trace: str)pip_services3_commons.errors.ApplicationException.ApplicationException

Sets a stack trace for this error.

This method returns reference to this error to implement Builder pattern to chain additional calls.

Parameters

stack_trace – a stack trace where this error occured

Returns

this error object

with_status(status: int)pip_services3_commons.errors.ApplicationException.ApplicationException

Sets a HTTP status code which shall be returned by REST calls. This method returns reference to this error to implement Builder pattern to chain additional calls.

Parameters

status – an HTTP error code.

Returns

this error object

wrap(cause: Any)pip_services3_commons.errors.ApplicationException.ApplicationException

Wraps another error into an application error object.

If original error is of ApplicationException type it is returned without changes. Otherwise a new ApplicationException is created and original error is set as its cause.

Parameters

cause – an original error object

Returns

an original or newly created ApplicationException

static wrap_error(error: pip_services3_commons.errors.ApplicationException.ApplicationException, cause: Any)pip_services3_commons.errors.ApplicationException.ApplicationException

Wraps another exception into specified application exception object.

If original exception is of ApplicationException type it is returned without changes. Otherwise the original error is set as a cause to specified ApplicationException object.

Parameters
  • error – an ApplicationException object to wrap the cause

  • cause – an original error object

Returns

an original or newly created ApplicationException

class pip_services3_commons.errors.ApplicationExceptionFactory

Bases: object

Factory to recreate exceptions from ErrorDescription values passed through the wire.

static create(description: pip_services3_commons.errors.ErrorDescription.ErrorDescription)pip_services3_commons.errors.ApplicationException.ApplicationException

Recreates ApplicationException object from serialized ErrorDescription.

It tries to restore original error type using type or error category fields.

Parameters

description – a serialized error description received as a result of remote call

Returns

ApplicationException object from serialized ErrorDescription.

exception pip_services3_commons.errors.BadRequestException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Errors due to improper user requests.

exception pip_services3_commons.errors.ConfigException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Errors related to mistakes in the microservice’s user-defined configurations.

exception pip_services3_commons.errors.ConflictException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Errors raised by conflicts between object versions that were posted by the user and those that are stored on the server.

exception pip_services3_commons.errors.ConnectionException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Errors happened during connection to remote services. They can be related to misconfiguration, network issues or remote service itself

class pip_services3_commons.errors.ErrorCategory

Bases: object

Defines standard error categories to application exceptions supported by PipServices toolkit.

BadRequest: str = 'BadRequest'

Errors due to improper user requests, like missing or wrong parameters

Conflict: str = 'Conflict'

Errors raised by conflict in object versions posted by user and stored on server.

FailedInvocation: str = 'FailedInvocation'

Errors returned by remote services or network during call attempts

FileError: str = 'FileError'

Errors in read/write file operations

Internal: str = 'Internal'

Internal errors caused by programming mistakes

InvalidState: str = 'InvalidState'

Errors related to operations called in wrong component state. For instance, business calls when component is not ready

Misconfiguration: str = 'Misconfiguration'

Errors related to mistakes in user-defined configuration

NoResponse: str = 'NoResponse'

Errors happened during connection to remote services. They can be related to misconfiguration, network issues or remote service itself

NotFound: str = 'NotFound'

Error caused by attempt to access missing object

Unauthorized: str = 'Unauthorized'

Access errors caused by missing user identity or security permissions

Unknown: str = 'Unknown'

Unknown or unexpected errors

Unsupported: str = 'Unsupported'

Errors caused by calls to unsupported or not yet implemented functionality

class pip_services3_commons.errors.ErrorDescription

Bases: object

Serializeable error description. It is use to pass information about errors between microservices implemented in different languages. On the receiving side ErrorDescription is used to recreate error object close to its original type without missing additional details.

static from_json(json: Dict[str, Any]) → Any
to_json() → Dict[str, Any]
class pip_services3_commons.errors.ErrorDescriptionFactory

Bases: object

Factory to create serializeable ErrorDescription from ApplicationException or from arbitrary errors.

The ErrorDescriptions are used to pass errors through the wire between microservices implemented in different languages. They allow to restore exceptions on the receiving side close to the original type and preserve additional information.

static create(ex: Any)pip_services3_commons.errors.ErrorDescription.ErrorDescription

Creates a serializable ErrorDescription from error object.

Parameters

ex – an error object

Returns

a serializeable ErrorDescription object that describes the error.

exception pip_services3_commons.errors.FileException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Errors in read/write local disk operations.

exception pip_services3_commons.errors.InternalException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Errors caused by programming mistakes

exception pip_services3_commons.errors.InvalidStateException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Errors related to calling operations, which require the component to be in a specific state.

For instance, business calls when component is not ready

exception pip_services3_commons.errors.InvocationException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Errors returned by remote services or by the network during call attempts.

exception pip_services3_commons.errors.NotFoundException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Error caused by attempt to access missing object

exception pip_services3_commons.errors.UnauthorizedException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Access errors caused by missing user identity (authentication error) or incorrect security permissions (authorization error).

exception pip_services3_commons.errors.UnknownException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Unknown or unexpected errors

exception pip_services3_commons.errors.UnsupportedException(correlation_id: Optional[str, None] = None, code: str = None, message: str = None)

Bases: pip_services3_commons.errors.ApplicationException.ApplicationException

Errors caused by calls to unsupported or not yet implemented functionality