package endpoints import ( "fmt" "regexp" "strings" "github.com/aws/aws-sdk-go-v2/aws" ) const ( defaultProtocol = "https" defaultSigner = "v4" ) var ( protocolPriority = []string{"https", "http"} signerPriority = []string{"v4"} ) // Options provide configuration needed to direct how endpoints are resolved. type Options struct { // Disable usage of HTTPS (TLS / SSL) DisableHTTPS bool } // Partitions is a slice of partition type Partitions []Partition // ResolveEndpoint resolves a service endpoint for the given region and options. func (ps Partitions) ResolveEndpoint(region string, opts Options) (aws.Endpoint, error) { if len(ps) == 0 { return aws.Endpoint{}, fmt.Errorf("no partitions found") } for i := 0; i < len(ps); i++ { if !ps[i].canResolveEndpoint(region) { continue } return ps[i].ResolveEndpoint(region, opts) } // fallback to first partition format to use when resolving the endpoint. return ps[0].ResolveEndpoint(region, opts) } // Partition is an AWS partition description for a service and its' region endpoints. type Partition struct { ID string RegionRegex *regexp.Regexp PartitionEndpoint string IsRegionalized bool Defaults Endpoint Endpoints Endpoints } func (p Partition) canResolveEndpoint(region string) bool { _, ok := p.Endpoints[region] return ok || p.RegionRegex.MatchString(region) } // ResolveEndpoint resolves and service endpoint for the given region and options. func (p Partition) ResolveEndpoint(region string, options Options) (resolved aws.Endpoint, err error) { if len(region) == 0 && len(p.PartitionEndpoint) != 0 { region = p.PartitionEndpoint } e, _ := p.endpointForRegion(region) return e.resolve(p.ID, region, p.Defaults, options), nil } func (p Partition) endpointForRegion(region string) (Endpoint, bool) { if e, ok := p.Endpoints[region]; ok { return e, true } if !p.IsRegionalized { return p.Endpoints[p.PartitionEndpoint], region == p.PartitionEndpoint } // Unable to find any matching endpoint, return // blank that will be used for generic endpoint creation. return Endpoint{}, false } // Endpoints is a map of service config regions to endpoints type Endpoints map[string]Endpoint // CredentialScope is the credential scope of a region and service type CredentialScope struct { Region string Service string } // Endpoint is a service endpoint description type Endpoint struct { // True if the endpoint cannot be resolved for this partition/region/service Unresolveable aws.Ternary Hostname string Protocols []string CredentialScope CredentialScope SignatureVersions []string `json:"signatureVersions"` } func (e Endpoint) resolve(partition, region string, def Endpoint, options Options) aws.Endpoint { var merged Endpoint merged.mergeIn(def) merged.mergeIn(e) e = merged var u string if e.Unresolveable != aws.TrueTernary { // Only attempt to resolve the endpoint if it can be resolved. hostname := strings.Replace(e.Hostname, "{region}", region, 1) scheme := getEndpointScheme(e.Protocols, options.DisableHTTPS) u = scheme + "://" + hostname } signingRegion := e.CredentialScope.Region if len(signingRegion) == 0 { signingRegion = region } signingName := e.CredentialScope.Service return aws.Endpoint{ URL: u, PartitionID: partition, SigningRegion: signingRegion, SigningName: signingName, SigningMethod: getByPriority(e.SignatureVersions, signerPriority, defaultSigner), } } func (e *Endpoint) mergeIn(other Endpoint) { if other.Unresolveable != aws.UnknownTernary { e.Unresolveable = other.Unresolveable } if len(other.Hostname) > 0 { e.Hostname = other.Hostname } if len(other.Protocols) > 0 { e.Protocols = other.Protocols } if len(other.CredentialScope.Region) > 0 { e.CredentialScope.Region = other.CredentialScope.Region } if len(other.CredentialScope.Service) > 0 { e.CredentialScope.Service = other.CredentialScope.Service } if len(other.SignatureVersions) > 0 { e.SignatureVersions = other.SignatureVersions } } func getEndpointScheme(protocols []string, disableHTTPS bool) string { if disableHTTPS { return "http" } return getByPriority(protocols, protocolPriority, defaultProtocol) } func getByPriority(s []string, p []string, def string) string { if len(s) == 0 { return def } for i := 0; i < len(p); i++ { for j := 0; j < len(s); j++ { if s[j] == p[i] { return s[j] } } } return s[0] }