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@jasdel @martonsereg @stefansundin @mikecook
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package endpoints
import (
"fmt"
"regexp"
"github.com/aws/aws-sdk-go/aws/awserr"
)
// Options provide the configuration needed to direct how the
// endpoints will be resolved.
type Options struct {
// DisableSSL forces the endpoint to be resolved as HTTP.
// instead of HTTPS if the service supports it.
DisableSSL bool
// Sets the resolver to resolve the endpoint as a dualstack endpoint
// for the service. If dualstack support for a service is not known and
// StrictMatching is not enabled a dualstack endpoint for the service will
// be returned. This endpoint may not be valid. If StrictMatching is
// enabled only services that are known to support dualstack will return
// dualstack endpoints.
UseDualStack bool
// Enables strict matching of services and regions resolved endpoints.
// If the partition doesn't enumerate the exact service and region an
// error will be returned. This option will prevent returning endpoints
// that look valid, but may not resolve to any real endpoint.
StrictMatching bool
// Enables resolving a service endpoint based on the region provided if the
// service does not exist. The service endpoint ID will be used as the service
// domain name prefix. By default the endpoint resolver requires the service
// to be known when resolving endpoints.
//
// If resolving an endpoint on the partition list the provided region will
// be used to determine which partition's domain name pattern to the service
// endpoint ID with. If both the service and region are unknown and resolving
// the endpoint on partition list an UnknownEndpointError error will be returned.
//
// If resolving and endpoint on a partition specific resolver that partition's
// domain name pattern will be used with the service endpoint ID. If both
// region and service do not exist when resolving an endpoint on a specific
// partition the partition's domain pattern will be used to combine the
// endpoint and region together.
//
// This option is ignored if StrictMatching is enabled.
ResolveUnknownService bool
}
// Set combines all of the option functions together.
func (o *Options) Set(optFns ...func(*Options)) {
for _, fn := range optFns {
fn(o)
}
}
// DisableSSLOption sets the DisableSSL options. Can be used as a functional
// option when resolving endpoints.
func DisableSSLOption(o *Options) {
o.DisableSSL = true
}
// UseDualStackOption sets the UseDualStack option. Can be used as a functional
// option when resolving endpoints.
func UseDualStackOption(o *Options) {
o.UseDualStack = true
}
// StrictMatchingOption sets the StrictMatching option. Can be used as a functional
// option when resolving endpoints.
func StrictMatchingOption(o *Options) {
o.StrictMatching = true
}
// ResolveUnknownServiceOption sets the ResolveUnknownService option. Can be used
// as a functional option when resolving endpoints.
func ResolveUnknownServiceOption(o *Options) {
o.ResolveUnknownService = true
}
// A Resolver provides the interface for functionality to resolve endpoints.
// The build in Partition and DefaultResolver return value satisfy this interface.
type Resolver interface {
EndpointFor(service, region string, opts ...func(*Options)) (ResolvedEndpoint, error)
}
// ResolverFunc is a helper utility that wraps a function so it satisfies the
// Resolver interface. This is useful when you want to add additional endpoint
// resolving logic, or stub out specific endpoints with custom values.
type ResolverFunc func(service, region string, opts ...func(*Options)) (ResolvedEndpoint, error)
// EndpointFor wraps the ResolverFunc function to satisfy the Resolver interface.
func (fn ResolverFunc) EndpointFor(service, region string, opts ...func(*Options)) (ResolvedEndpoint, error) {
return fn(service, region, opts...)
}
var schemeRE = regexp.MustCompile("^([^:]+)://")
// AddScheme adds the HTTP or HTTPS schemes to a endpoint URL if there is no
// scheme. If disableSSL is true HTTP will set HTTP instead of the default HTTPS.
//
// If disableSSL is set, it will only set the URL's scheme if the URL does not
// contain a scheme.
func AddScheme(endpoint string, disableSSL bool) string {
if !schemeRE.MatchString(endpoint) {
scheme := "https"
if disableSSL {
scheme = "http"
}
endpoint = fmt.Sprintf("%s://%s", scheme, endpoint)
}
return endpoint
}
// EnumPartitions a provides a way to retrieve the underlying partitions that
// make up the SDK's default Resolver, or any resolver decoded from a model
// file.
//
// Use this interface with DefaultResolver and DecodeModels to get the list of
// Partitions.
type EnumPartitions interface {
Partitions() []Partition
}
// RegionsForService returns a map of regions for the partition and service.
// If either the partition or service does not exist false will be returned
// as the second parameter.
//
// This example shows how to get the regions for DynamoDB in the AWS partition.
// rs, exists := endpoints.RegionsForService(endpoints.DefaultPartitions(), endpoints.AwsPartitionID, endpoints.DynamodbServiceID)
//
// This is equivalent to using the partition directly.
// rs := endpoints.AwsPartition().Services()[endpoints.DynamodbServiceID].Regions()
func RegionsForService(ps []Partition, partitionID, serviceID string) (map[string]Region, bool) {
for _, p := range ps {
if p.ID() != partitionID {
continue
}
if _, ok := p.p.Services[serviceID]; !ok {
break
}
s := Service{
id: serviceID,
p: p.p,
}
return s.Regions(), true
}
return map[string]Region{}, false
}
// PartitionForRegion returns the first partition which includes the region
// passed in. This includes both known regions and regions which match
// a pattern supported by the partition which may include regions that are
// not explicitly known by the partition. Use the Regions method of the
// returned Partition if explicit support is needed.
func PartitionForRegion(ps []Partition, regionID string) (Partition, bool) {
for _, p := range ps {
if _, ok := p.p.Regions[regionID]; ok || p.p.RegionRegex.MatchString(regionID) {
return p, true
}
}
return Partition{}, false
}
// A Partition provides the ability to enumerate the partition's regions
// and services.
type Partition struct {
id string
p *partition
}
// ID returns the identifier of the partition.
func (p Partition) ID() string { return p.id }
// EndpointFor attempts to resolve the endpoint based on service and region.
// See Options for information on configuring how the endpoint is resolved.
//
// If the service cannot be found in the metadata the UnknownServiceError
// error will be returned. This validation will occur regardless if
// StrictMatching is enabled. To enable resolving unknown services set the
// "ResolveUnknownService" option to true. When StrictMatching is disabled
// this option allows the partition resolver to resolve a endpoint based on
// the service endpoint ID provided.
//
// When resolving endpoints you can choose to enable StrictMatching. This will
// require the provided service and region to be known by the partition.
// If the endpoint cannot be strictly resolved an error will be returned. This
// mode is useful to ensure the endpoint resolved is valid. Without
// StrictMatching enabled the endpoint returned my look valid but may not work.
// StrictMatching requires the SDK to be updated if you want to take advantage
// of new regions and services expansions.
//
// Errors that can be returned.
// * UnknownServiceError
// * UnknownEndpointError
func (p Partition) EndpointFor(service, region string, opts ...func(*Options)) (ResolvedEndpoint, error) {
return p.p.EndpointFor(service, region, opts...)
}
// Regions returns a map of Regions indexed by their ID. This is useful for
// enumerating over the regions in a partition.
func (p Partition) Regions() map[string]Region {
rs := map[string]Region{}
for id, r := range p.p.Regions {
rs[id] = Region{
id: id,
desc: r.Description,
p: p.p,
}
}
return rs
}
// Services returns a map of Service indexed by their ID. This is useful for
// enumerating over the services in a partition.
func (p Partition) Services() map[string]Service {
ss := map[string]Service{}
for id := range p.p.Services {
ss[id] = Service{
id: id,
p: p.p,
}
}
return ss
}
// A Region provides information about a region, and ability to resolve an
// endpoint from the context of a region, given a service.
type Region struct {
id, desc string
p *partition
}
// ID returns the region's identifier.
func (r Region) ID() string { return r.id }
// Description returns the region's description. The region description
// is free text, it can be empty, and it may change between SDK releases.
func (r Region) Description() string { return r.desc }
// ResolveEndpoint resolves an endpoint from the context of the region given
// a service. See Partition.EndpointFor for usage and errors that can be returned.
func (r Region) ResolveEndpoint(service string, opts ...func(*Options)) (ResolvedEndpoint, error) {
return r.p.EndpointFor(service, r.id, opts...)
}
// Services returns a list of all services that are known to be in this region.
func (r Region) Services() map[string]Service {
ss := map[string]Service{}
for id, s := range r.p.Services {
if _, ok := s.Endpoints[r.id]; ok {
ss[id] = Service{
id: id,
p: r.p,
}
}
}
return ss
}
// A Service provides information about a service, and ability to resolve an
// endpoint from the context of a service, given a region.
type Service struct {
id string
p *partition
}
// ID returns the identifier for the service.
func (s Service) ID() string { return s.id }
// ResolveEndpoint resolves an endpoint from the context of a service given
// a region. See Partition.EndpointFor for usage and errors that can be returned.
func (s Service) ResolveEndpoint(region string, opts ...func(*Options)) (ResolvedEndpoint, error) {
return s.p.EndpointFor(s.id, region, opts...)
}
// Regions returns a map of Regions that the service is present in.
//
// A region is the AWS region the service exists in. Whereas a Endpoint is
// an URL that can be resolved to a instance of a service.
func (s Service) Regions() map[string]Region {
rs := map[string]Region{}
for id := range s.p.Services[s.id].Endpoints {
if r, ok := s.p.Regions[id]; ok {
rs[id] = Region{
id: id,
desc: r.Description,
p: s.p,
}
}
}
return rs
}
// Endpoints returns a map of Endpoints indexed by their ID for all known
// endpoints for a service.
//
// A region is the AWS region the service exists in. Whereas a Endpoint is
// an URL that can be resolved to a instance of a service.
func (s Service) Endpoints() map[string]Endpoint {
es := map[string]Endpoint{}
for id := range s.p.Services[s.id].Endpoints {
es[id] = Endpoint{
id: id,
serviceID: s.id,
p: s.p,
}
}
return es
}
// A Endpoint provides information about endpoints, and provides the ability
// to resolve that endpoint for the service, and the region the endpoint
// represents.
type Endpoint struct {
id string
serviceID string
p *partition
}
// ID returns the identifier for an endpoint.
func (e Endpoint) ID() string { return e.id }
// ServiceID returns the identifier the endpoint belongs to.
func (e Endpoint) ServiceID() string { return e.serviceID }
// ResolveEndpoint resolves an endpoint from the context of a service and
// region the endpoint represents. See Partition.EndpointFor for usage and
// errors that can be returned.
func (e Endpoint) ResolveEndpoint(opts ...func(*Options)) (ResolvedEndpoint, error) {
return e.p.EndpointFor(e.serviceID, e.id, opts...)
}
// A ResolvedEndpoint is an endpoint that has been resolved based on a partition
// service, and region.
type ResolvedEndpoint struct {
// The endpoint URL
URL string
// The region that should be used for signing requests.
SigningRegion string
// The service name that should be used for signing requests.
SigningName string
// States that the signing name for this endpoint was derived from metadata
// passed in, but was not explicitly modeled.
SigningNameDerived bool
// The signing method that should be used for signing requests.
SigningMethod string
}
// So that the Error interface type can be included as an anonymous field
// in the requestError struct and not conflict with the error.Error() method.
type awsError awserr.Error
// A EndpointNotFoundError is returned when in StrictMatching mode, and the
// endpoint for the service and region cannot be found in any of the partitions.
type EndpointNotFoundError struct {
awsError
Partition string
Service string
Region string
}
// A UnknownServiceError is returned when the service does not resolve to an
// endpoint. Includes a list of all known services for the partition. Returned
// when a partition does not support the service.
type UnknownServiceError struct {
awsError
Partition string
Service string
Known []string
}
// NewUnknownServiceError builds and returns UnknownServiceError.
func NewUnknownServiceError(p, s string, known []string) UnknownServiceError {
return UnknownServiceError{
awsError: awserr.New("UnknownServiceError",
"could not resolve endpoint for unknown service", nil),
Partition: p,
Service: s,
Known: known,
}
}
// String returns the string representation of the error.
func (e UnknownServiceError) Error() string {
extra := fmt.Sprintf("partition: %q, service: %q",
e.Partition, e.Service)
if len(e.Known) > 0 {
extra += fmt.Sprintf(", known: %v", e.Known)
}
return awserr.SprintError(e.Code(), e.Message(), extra, e.OrigErr())
}
// String returns the string representation of the error.
func (e UnknownServiceError) String() string {
return e.Error()
}
// A UnknownEndpointError is returned when in StrictMatching mode and the
// service is valid, but the region does not resolve to an endpoint. Includes
// a list of all known endpoints for the service.
type UnknownEndpointError struct {
awsError
Partition string
Service string
Region string
Known []string
}
// NewUnknownEndpointError builds and returns UnknownEndpointError.
func NewUnknownEndpointError(p, s, r string, known []string) UnknownEndpointError {
return UnknownEndpointError{
awsError: awserr.New("UnknownEndpointError",
"could not resolve endpoint", nil),
Partition: p,
Service: s,
Region: r,
Known: known,
}
}
// String returns the string representation of the error.
func (e UnknownEndpointError) Error() string {
extra := fmt.Sprintf("partition: %q, service: %q, region: %q",
e.Partition, e.Service, e.Region)
if len(e.Known) > 0 {
extra += fmt.Sprintf(", known: %v", e.Known)
}
return awserr.SprintError(e.Code(), e.Message(), extra, e.OrigErr())
}
// String returns the string representation of the error.
func (e UnknownEndpointError) String() string {
return e.Error()
}
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