goa: goa.design/goa Index | Files | Directories

package goa

import "goa.design/goa"

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

Package Files

doc.go endpoint.go error.go validation.go

Constants

❖
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
)
❖
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"
)

func DecodePayloadError Uses

❖
func DecodePayloadError(msg string) error

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

func InvalidEnumValueError Uses

❖
func InvalidEnumValueError(name string, val interface{}, allowed []interface{}) 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 Uses

❖
func InvalidFieldTypeError(name string, val interface{}, 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 Uses

❖
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 Uses

❖
func InvalidLengthError(name string, target interface{}, 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 Uses

❖
func InvalidPatternError(name, target string, 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 Uses

❖
func InvalidRangeError(name string, target interface{}, value interface{}, 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 Uses

❖
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 Uses

❖
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 Uses

❖
func MissingPayloadError() error

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

func NewErrorID Uses

❖
func NewErrorID() string

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

func ValidateFormat Uses

❖
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 Uses

❖
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.

type Endpoint Uses

❖
type Endpoint func(ctx context.Context, request interface{}) (response interface{}, err error)

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

type Format Uses

❖
type Format string

Format defines a validation format.

type ServiceError Uses

❖
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
    // 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
}

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

func Fault Uses

❖
func Fault(format string, v ...interface{}) *ServiceError

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

func PermanentError Uses

❖
func PermanentError(name, format string, v ...interface{}) *ServiceError

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

func PermanentTimeoutError Uses

❖
func PermanentTimeoutError(name, format string, v ...interface{}) *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 Uses

❖
func TemporaryError(name, format string, v ...interface{}) *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 Uses

❖
func TemporaryTimeoutError(name, format string, v ...interface{}) *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 Uses

❖
func (s *ServiceError) Error() string

Error returns the error message.

func (*ServiceError) ErrorName Uses

❖
func (s *ServiceError) ErrorName() string

ErrorName returns the error name.

Directories

PathSynopsis
codegenPackage codegen contains data structures and algorithms used by the Goa code generation tool.
codegen/cliPackage cli contains helpers used by transport-specific command-line client generators for parsing the command-line flags to identify the service and the method to make a request along with the request payload to be sent.
codegen/examplePackage example contains code generation algorithms to produce an example server and client implementation for the transports defined in the design.
codegen/generatorPackage generator contains the code generation algorithms for a service server, client, and OpenAPI specification.
codegen/servicePackage service contains the code generation algorithms to produce code for the service and views packages and dummy implementation for the services defined in the design.
dslPackage dsl implements the Goa DSL.
evalPackage eval implements a DSL engine for executing arbitrary Go DSLs.
exprPackage expr defines expressions and data types used by the DSL and the code generators.
grpcPackage grpc contains code generation logic to produce a server that serves gRPC requests and a client that encode requests to and decode responses from a gRPC server.
grpc/codegenPackage codegen contains the code generation logic to generate gRPC service definitions (.proto files) from the design DSLs and the corresponding server and client code that wraps the goa-generated endpoints with the protocol buffer compiler (protoc) generated clients and servers.
grpc/middlewarePackage middleware contains gRPC server and client interceptors that wraps unary and streaming RPCs to provide additional functionality.
grpc/middleware/xrayPackage xray contains unary and streaming server and client interceptors that create AWS X-Ray segments from the gRPC requests and responses and send the segments to an AWS X-ray daemon.
grpc/pbPackage goapb contains protocol buffer message types used by the code generation logic.
httpPackage http contains HTTP specific constructs that complement the code generated by Goa.
http/codegenPackage codegen contains code generation logic to generate HTTP server and client that wrap the generated goa endpoint and the OpenAPI 2.0 specifications for the HTTP endpoints.
http/codegen/openapiPackage openapi produces OpenAPI Specification 2.0 (https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md) for the HTTP endpoints.
http/middlewarePackage middleware contains HTTP middlewares that wrap a HTTP handler to provide additional functionality.
http/middleware/xrayPackage xray contains middleware that creates AWS X-Ray segments from the HTTP requests and responses and send the segments to an AWS X-ray daemon.
middlewarePackage middleware contains transport independent middlewares.
middleware/xrayPackage xray contains the AWS X-Ray segment document type populated by the transport-specific X-Ray middleware.
middleware/xray/xraytestPackage xraytest contains test helpers for package xray that are used by transport-specific X-Ray middleware tests.
pkgPackage pkg deals with versioning for goa.
securityPackage security contains the types used by the code generators to secure goa endpoint.

Package goa imports 14 packages (graph) and is imported by 15 packages. Updated 2020-03-09. Refresh now. Tools for package owners.