goa

package
v3.19.1 Latest Latest
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 Go to latest Published: Sep 23, 2024 License: MIT Imports: 17 Imported by: 1,289

Documentation

Overview

Package goa implements a Go framework for writing microservices that promotes best practice by providing a single source of truth from which server code, client code, and documentation is derived. The code generated by goa follows the clean architecture pattern where composable modules are generated for the transport, endpoint, and business logic layers. The goa package contains middleware, plugins, and other complementary functionality that can be leveraged in tandem with the generated code to implement complete microservices in an efficient manner. By using Goa for developing microservices, implementers don’t have to worry with the documentation getting out of sync from the implementation as goa takes care of generating OpenAPI specifications for HTTP based services and gRPC protocol buffer files for gRPC based services (or both if the service supports both transports). Reviewers can also be assured that the implementation follows the documentation as the code is generated from the same source.

Visit https://goa.design for more information.

Index

Constants

View Source 
const (
	// MethodKey is the request context key used to store the name of the
	// method as defined in the design. The generated transport code
	// initializes the corresponding value prior to invoking the endpoint.
	MethodKey contextKey = iota + 1

	// ServiceKey is the request context key used to store the name of the
	// service as defined in the design. The generated transport code
	// initializes the corresponding value prior to invoking the endpoint.
	ServiceKey
)
View Source 
const (
	// InvalidFieldType is the error name for invalid field type errors.
	InvalidFieldType = "invalid_field_type"
	// MissingField is the error name for missing field errors.
	MissingField = "missing_field"
	// InvalidEnumValue is the error name for invalid enum value errors.
	InvalidEnumValue = "invalid_enum_value"
	// InvalidFormat is the error name for invalid format errors.
	InvalidFormat = "invalid_format"
	// InvalidPattern is the error name for invalid pattern errors.
	InvalidPattern = "invalid_pattern"
	// InvalidRange is the error name for invalid range errors.
	InvalidRange = "invalid_range"
	// InvalidLength is the error name for invalid length errors.
	InvalidLength = "invalid_length"
	// UnsupportedMediaType is the error name returned by the Goa decoder
	// when the content type of the HTTP request body is not supported.
	UnsupportedMediaType = "unsupported_media_type"
)
View Source 
const (
	// FormatDate describes RFC3339 date values.
	FormatDate Format = "date"

	// FormatDateTime describes RFC3339 date time values.
	FormatDateTime Format = "date-time"

	// FormatUUID describes RFC4122 UUID values.
	FormatUUID = "uuid"

	// FormatEmail describes RFC5322 email addresses.
	FormatEmail = "email"

	// FormatHostname describes RFC1035 Internet hostnames.
	FormatHostname = "hostname"

	// FormatIPv4 describes RFC2373 IPv4 address values.
	FormatIPv4 = "ipv4"

	// FormatIPv6 describes RFC2373 IPv6 address values.
	FormatIPv6 = "ipv6"

	// FormatIP describes RFC2373 IPv4 or IPv6 address values.
	FormatIP = "ip"

	// FormatURI describes RFC3986 URI values.
	FormatURI = "uri"

	// FormatMAC describes IEEE 802 MAC-48, EUI-48 or EUI-64 MAC address values.
	FormatMAC = "mac"

	// FormatCIDR describes RFC4632 and RFC4291 CIDR notation IP address values.
	FormatCIDR = "cidr"

	// FormatRegexp describes regular expression syntax accepted by RE2.
	FormatRegexp = "regexp"

	// FormatJSON describes JSON text.
	FormatJSON = "json"

	// FormatRFC1123 describes RFC1123 date time values.
	FormatRFC1123 = "rfc1123"
)
View Source 
const (
	// Major version number
	Major = 3
	// Minor version number
	Minor = 19
	// Build number
	Build = 1
	// Suffix - set to empty string in release tag commits.
	Suffix = ""
)

Variables

This section is empty.

Functions

func Compatible 

func Compatible(v string) (bool, error)

Compatible returns true if Major matches the major version of the given version string. It returns an error if the given string is not a valid version string.

func DecodePayloadError added in v3.0.1 

func DecodePayloadError(msg string) error

DecodePayloadError is the error produced by the generated code when a request body cannot be decoded successfully.

func InvalidEnumValueError added in v3.0.1 

func InvalidEnumValueError(name string, val any, allowed []any) error

InvalidEnumValueError is the error produced by the generated code when the value of a payload field does not match one the values defined in the design Enum validation.

func InvalidFieldTypeError added in v3.0.1 

func InvalidFieldTypeError(name string, val any, expected string) error

InvalidFieldTypeError is the error produced by the generated code when the type of a payload field does not match the type defined in the design.

func InvalidFormatError added in v3.0.1 

func InvalidFormatError(name, target string, format Format, formatError error) error

InvalidFormatError is the error produced by the generated code when the value of a payload field does not match the format validation defined in the design.

func InvalidLengthError added in v3.0.1 

func InvalidLengthError(name string, target any, ln, value int, min bool) error

InvalidLengthError is the error produced by the generated code when the value of a payload field does not match the length validation defined in the design.

func InvalidPatternError added in v3.0.1 

func InvalidPatternError(name, target, pattern string) error

InvalidPatternError is the error produced by the generated code when the value of a payload field does not match the pattern validation defined in the design.

func InvalidRangeError added in v3.0.1 

func InvalidRangeError(name string, target, value any, min bool) error

InvalidRangeError is the error produced by the generated code when the value of a payload field does not match the range validation defined in the design. value may be an int or a float64.

func MergeErrors added in v3.0.1 

func MergeErrors(err, other error) error

MergeErrors updates an error by merging another into it. It first converts other into a ServiceError if not already one. The merge algorithm then:

* uses the name of err if a ServiceError, the name of other otherwise.

* appends both error messages.

* computes Timeout and Temporary by "and"ing the fields of both errors.

Merge returns the updated error. This makes it possible to return other when err is nil.

func MissingFieldError added in v3.0.1 

func MissingFieldError(name, context string) error

MissingFieldError is the error produced by the generated code when a payload is missing a required field.

func MissingPayloadError added in v3.0.1 

func MissingPayloadError() error

MissingPayloadError is the error produced by the generated code when a request is missing a required payload.

func NewErrorID added in v3.0.1 

func NewErrorID() string

NewErrorID creates a unique 8 character ID that is well suited to use as an error identifier.

func SkipResponseWriter added in v3.17.0 

func SkipResponseWriter(wt io.WriterTo) io.ReadCloser

SkipResponseWriter converts an io.WriterTo into a io.ReadCloser. The Read/Close methods this function returns will pipe the Write calls that wt makes, to implement a Reader that has the written bytes. If Read is called Close must also be called to avoid leaking memory. The returned value implements io.WriterTo as well, so the generated handler will call that instead of the Read method.

Server handlers that use SkipResponseBodyEncodeDecode() io.ReadCloser as a return type.

func UnsupportedMediaTypeError added in v3.16.2 

func UnsupportedMediaTypeError(ct string) error

UnsupportedMediaTypeError is the error produced by the Goa decoder when the content type of the HTTP request body is not supported.

func ValidateFormat added in v3.0.1 

func ValidateFormat(name string, val string, f Format) error

ValidateFormat validates val against f. It returns nil if the string conforms to the format, an error otherwise. name is the name of the variable used in error messages. where in a data structure the error occurred if any. The format specification follows the json schema draft 4 validation extension. see http://json-schema.org/latest/json-schema-validation.html#anchor105 Supported formats are:

  • "date": RFC3339 date value
  • "date-time": RFC3339 date time value
  • "email": RFC5322 email address
  • "hostname": RFC1035 Internet host name
  • "ipv4", "ipv6", "ip": RFC2673 and RFC2373 IP address values
  • "uri": RFC3986 URI value
  • "mac": IEEE 802 MAC-48, EUI-48 or EUI-64 MAC address value
  • "cidr": RFC4632 and RFC4291 CIDR notation IP address value
  • "regexp": Regular expression syntax accepted by RE2
  • "rfc1123": RFC1123 date time value

func ValidatePattern added in v3.0.1 

func ValidatePattern(name, val, p string) error

ValidatePattern returns an error if val does not match the regular expression p. It makes an effort to minimize the number of times the regular expression needs to be compiled. name is the name of the variable used in error messages.

func Version 

func Version() string

Version returns the complete version number.

Types

type Endpoint added in v3.0.1 

type Endpoint func(ctx context.Context, request any) (response any, err error)

Endpoint exposes service methods to remote clients independently of the underlying transport.

type Format added in v3.0.1 

type Format string

Format defines a validation format.

type GoaErrorNamer added in v3.9.1 

type GoaErrorNamer interface {
	GoaErrorName() string
}

GoaErrorNamer is an interface implemented by generated error structs that exposes the name of the error as defined in the design.

type ServiceError added in v3.0.1 

type ServiceError struct {
	// Name is a name for that class of errors.
	Name string
	// ID is a unique value for each occurrence of the error.
	ID string
	// Pointer to the field that caused this error, if appropriate
	Field *string
	// Message contains the specific error details.
	Message string
	// Is the error a timeout?
	Timeout bool
	// Is the error temporary?
	Temporary bool
	// Is the error a server-side fault?
	Fault bool
	// contains filtered or unexported fields
}

ServiceError is the default error type used by the goa package to encode and decode error responses.

func Fault added in v3.0.1 

func Fault(format string, v ...any) *ServiceError

Fault creates an error given a format and values a la fmt.Printf. The error has the Fault field set to true.

func NewServiceError added in v3.7.12 

func NewServiceError(err error, name string, timeout, temporary, fault bool) *ServiceError

NewServiceError creates an error.

func PermanentError added in v3.0.1 

func PermanentError(name, format string, v ...any) *ServiceError

PermanentError creates an error given a name and a format and values a la fmt.Printf.

func PermanentTimeoutError added in v3.0.1 

func PermanentTimeoutError(name, format string, v ...any) *ServiceError

PermanentTimeoutError creates an error given a name and a format and values a la fmt.Printf. The error has the Timeout field set to true.

func TemporaryError added in v3.0.1 

func TemporaryError(name, format string, v ...any) *ServiceError

TemporaryError is an error class that indicates that the error is temporary and that retrying the request may be successful. TemporaryError creates an error given a name and a format and values a la fmt.Printf. The error has the Temporary field set to true.

func TemporaryTimeoutError added in v3.0.1 

func TemporaryTimeoutError(name, format string, v ...any) *ServiceError

TemporaryTimeoutError creates an error given a name and a format and values a la fmt.Printf. The error has both the Timeout and Temporary fields set to true.

func (*ServiceError) Error added in v3.0.1 

func (e *ServiceError) Error() string

Error returns the error message.

func (*ServiceError) ErrorName deprecated added in v3.0.1 

func (e *ServiceError) ErrorName() string

ErrorName returns the error name.

Deprecated: Use GoaErrorName - https://github.com/goadesign/goa/issues/3105

func (*ServiceError) GoaErrorName added in v3.8.6 

func (e *ServiceError) GoaErrorName() string

GoaErrorName returns the error name.

func (*ServiceError) History added in v3.5.3 

func (e *ServiceError) History() []*ServiceError

History returns the history of error revisions, ignoring the result of any merges.

func (*ServiceError) Unwrap added in v3.7.12 

func (e *ServiceError) Unwrap() error

type WriterToFunc added in v3.17.0 

type WriterToFunc func(w io.Writer) (err error)

WriterToFunc impelments io.WriterTo. The io.Writer passed to the function will be wrapped.

func (WriterToFunc) WriteTo added in v3.17.0 

func (fn WriterToFunc) WriteTo(w io.Writer) (n int64, err error)

WriteTo writes to w.

The value in w is wrapped when passed to fn keeping track of how bytes are written by fn.

Source Files

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