problem

Documentation

Overview

Package problem provides utility functions for rendering errors as RFC7807 compatible responses.

RFC7807: https://tools.ietf.org/html/rfc7807

The P type is used to define application problems. The Render function is used to serialize problems in a HTTP response.

Index

• Constants
• Variables
• func IsKnownError(err error) error
• func RegisterError(err error, p P)
• func RegisterHost(host string)
• func RegisterReportFunc(fn ReportFunc)
• func Render(ctx context.Context, w http.ResponseWriter, err error)
• func SetLogFilter(filter LogFilter)
• func UnRegisterErrors()
• type LogFilter
• type P
  • func MakeInvalidFieldProblem(name string, reason error) *P
  • func NewProblemWithInvalidField(p P, name string, reason error) *P
  • func (p P) Error() string
• type Problem
  • func New(serviceHost string, log *log.Entry, filter LogFilter) *Problem
  • func (ps *Problem) IsKnownError(err error) error
  • func (ps *Problem) RegisterError(err error, p P)
  • func (ps *Problem) RegisterHost(host string)
  • func (ps *Problem) RegisterReportFunc(fn ReportFunc)
  • func (ps *Problem) Render(ctx context.Context, w http.ResponseWriter, err error)
  • func (ps *Problem) ServiceHost() string
  • func (ps *Problem) SetLogFilter(filter LogFilter)
  • func (ps *Problem) UnRegisterErrors()
• type ReportFunc

Constants

const (

	// LogNoErrors indicates that the Problem instance should not log any errors
	LogNoErrors = LogFilter(iota)
	// LogUnknownErrors indicates that the Problem instance should only log errors
	// which are not registered
	LogUnknownErrors = LogFilter(iota)
	// LogAllErrors indicates that the Problem instance should log all errors
	LogAllErrors = LogFilter(iota)
)

Variables

var (
	// ServerError is a well-known problem type. Use it as a shortcut.
	ServerError = P{
		Type:   "server_error",
		Title:  "Internal Server Error",
		Status: http.StatusInternalServerError,
		Detail: "An error occurred while processing this request.  This is usually due " +
			"to a bug within the server software.  Trying this request again may " +
			"succeed if the bug is transient. Otherwise, please contact the system " +
			"administrator.",
	}

	// NotFound is a well-known problem type.  Use it as a shortcut in your actions
	NotFound = P{
		Type:   "not_found",
		Title:  "Resource Missing",
		Status: http.StatusNotFound,
		Detail: "The resource at the url requested was not found.  This usually " +
			"occurs for one of two reasons:  The url requested is not valid, or no " +
			"data in our database could be found with the parameters provided.",
	}

	// BadRequest is a well-known problem type.  Use it as a shortcut
	// in your actions.
	BadRequest = P{
		Type:   "bad_request",
		Title:  "Bad Request",
		Status: http.StatusBadRequest,
		Detail: "The request you sent was invalid in some way.",
	}
)

var Default = New(DefaultServiceHost, DefaultLogger, LogAllErrors)

Default is the problem instance used by the package functions providing a global state registry and rendering of problems for an application. For a non-global state registry instantiate a new Problem with New.

var DefaultLogger = log.DefaultLogger

DefaultLogger is the default logger used with the default problem instance.

var DefaultServiceHost = "https://hcnet.org/aurora-errors/"

DefaultServiceHost is the default service host used with the default problem instance.

Functions

func IsKnownError

func IsKnownError(err error) error

IsKnownError maps an error to a list of known errors

func RegisterError

func RegisterError(err error, p P)

RegisterError records an error -> P mapping, allowing the app to register specific errors that may occur in other packages to be rendered as a specific P instance.

For example, you might want to render any sql.ErrNoRows errors as a problem.NotFound, and you would do so by calling:

problem.RegisterError(sql.ErrNoRows, problem.NotFound) in you application initialization sequence

func RegisterHost

func RegisterHost(host string)

RegisterHost registers the service host url. It is used to prepend the host url to the error type. If you don't wish to prepend anything to the error type, register host as an empty string. The default service host points to `https://hcnet.org/aurora-errors/`.

func RegisterReportFunc

func RegisterReportFunc(fn ReportFunc)

RegisterReportFunc registers the report function that you want to use to report errors. Once reportFn is initialzied, it will be used to report unexpected errors.

func Render

func Render(ctx context.Context, w http.ResponseWriter, err error)

Render writes a http response to `w`, compliant with the "Problem Details for HTTP APIs" RFC: https://tools.ietf.org/html/draft-ietf-appsawg-http-problem-00

func SetLogFilter

func SetLogFilter(filter LogFilter)

SetLogFilter sets log filter of the default Problem

func UnRegisterErrors

func UnRegisterErrors()

UnRegisterErrors removes all registered errors

Types

type LogFilter

type LogFilter int

LogFilter describes which errors should be logged when terminating requests in Problem.Render()

type P

type P struct {
	Type   string                 `json:"type"`
	Title  string                 `json:"title"`
	Status int                    `json:"status"`
	Detail string                 `json:"detail,omitempty"`
	Extras map[string]interface{} `json:"extras,omitempty"`
}

P is a struct that represents an error response to be rendered to a connected client.

func MakeInvalidFieldProblem

func MakeInvalidFieldProblem(name string, reason error) *P

MakeInvalidFieldProblem is a helper function to make a BadRequest with extras

func NewProblemWithInvalidField

func NewProblemWithInvalidField(p P, name string, reason error) *P

NewProblemWithInvalidField creates a copy of the given problem, setting the invalid_field key in extras with the given reason.

func (P) Error

func (p P) Error() string

type Problem

type Problem struct {
	// contains filtered or unexported fields
}

Problem is an instance of the functionality served by the problem package.

func New

func New(serviceHost string, log *log.Entry, filter LogFilter) *Problem

New returns a new instance of Problem.

func (*Problem) IsKnownError

func (ps *Problem) IsKnownError(err error) error

IsKnownError maps an error to a list of known errors

func (*Problem) RegisterError

func (ps *Problem) RegisterError(err error, p P)

RegisterError records an error -> P mapping, allowing the app to register specific errors that may occur in other packages to be rendered as a specific P instance.

For example, you might want to render any sql.ErrNoRows errors as a problem.NotFound, and you would do so by calling:

problem.RegisterError(sql.ErrNoRows, problem.NotFound) in you application initialization sequence

func (*Problem) RegisterHost

func (ps *Problem) RegisterHost(host string)

RegisterHost registers the service host url. It is used to prepend the host url to the error type. If you don't wish to prepend anything to the error type, register host as an empty string.

func (*Problem) RegisterReportFunc

func (ps *Problem) RegisterReportFunc(fn ReportFunc)

RegisterReportFunc registers the report function that you want to use to report errors. Once reportFn is initialzied, it will be used to report unexpected errors.

func (*Problem) Render

func (ps *Problem) Render(ctx context.Context, w http.ResponseWriter, err error)

Render writes a http response to `w`, compliant with the "Problem Details for HTTP APIs" RFC: https://www.rfc-editor.org/rfc/rfc7807.txt

func (*Problem) ServiceHost

func (ps *Problem) ServiceHost() string

ServiceHost returns the service host the Problem instance is configured with.

func (*Problem) SetLogFilter

func (ps *Problem) SetLogFilter(filter LogFilter)

SetLogFilter sets log filter

func (*Problem) UnRegisterErrors

func (ps *Problem) UnRegisterErrors()

UnRegisterErrors removes all registered errors

type ReportFunc

type ReportFunc func(context.Context, error)

ReportFunc is a function type used to report unexpected errors.