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// Package defaults is a collection of helpers to retrieve the SDK's default
// configuration and handlers.
//
// Generally this package shouldn't be used directly, but session.Session
// instead. This package is useful when you need to reset the defaults
// of a session or service client to the SDK defaults before setting
// additional parameters.
package defaults
import (
"fmt"
"net/http"
"os"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/corehandlers"
"github.com/aws/aws-sdk-go/aws/credentials"
"github.com/aws/aws-sdk-go/aws/credentials/ec2rolecreds"
"github.com/aws/aws-sdk-go/aws/credentials/endpointcreds"
"github.com/aws/aws-sdk-go/aws/ec2metadata"
"github.com/aws/aws-sdk-go/aws/endpoints"
"github.com/aws/aws-sdk-go/aws/request"
)
// A Defaults provides a collection of default values for SDK clients.
type Defaults struct {
Config *aws.Config
Handlers request.Handlers
}
// Get returns the SDK's default values with Config and handlers pre-configured.
func Get() Defaults {
cfg := Config()
handlers := Handlers()
cfg.Credentials = CredChain(cfg, handlers)
return Defaults{
Config: cfg,
Handlers: handlers,
}
}
// Config returns the default configuration without credentials.
// To retrieve a config with credentials also included use
// `defaults.Get().Config` instead.
//
// Generally you shouldn't need to use this method directly, but
// is available if you need to reset the configuration of an
// existing service client or session.
func Config() *aws.Config {
return aws.NewConfig().
WithCredentials(credentials.AnonymousCredentials).
WithRegion(os.Getenv("AWS_REGION")).
WithHTTPClient(http.DefaultClient).
WithMaxRetries(aws.UseServiceDefaultRetries).
WithLogger(aws.NewDefaultLogger()).
WithLogLevel(aws.LogOff).
WithSleepDelay(time.Sleep).
WithEndpointResolver(endpoints.DefaultResolver())
}
// Handlers returns the default request handlers.
//
// Generally you shouldn't need to use this method directly, but
// is available if you need to reset the request handlers of an
// existing service client or session.
func Handlers() request.Handlers {
var handlers request.Handlers
handlers.Validate.PushBackNamed(corehandlers.ValidateEndpointHandler)
handlers.Validate.AfterEachFn = request.HandlerListStopOnError
handlers.Build.PushBackNamed(corehandlers.SDKVersionUserAgentHandler)
handlers.Build.AfterEachFn = request.HandlerListStopOnError
handlers.Sign.PushBackNamed(corehandlers.BuildContentLengthHandler)
handlers.Send.PushBackNamed(corehandlers.ValidateReqSigHandler)
handlers.Send.PushBackNamed(corehandlers.SendHandler)
handlers.AfterRetry.PushBackNamed(corehandlers.AfterRetryHandler)
handlers.ValidateResponse.PushBackNamed(corehandlers.ValidateResponseHandler)
return handlers
}
// CredChain returns the default credential chain.
//
// Generally you shouldn't need to use this method directly, but
// is available if you need to reset the credentials of an
// existing service client or session's Config.
func CredChain(cfg *aws.Config, handlers request.Handlers) *credentials.Credentials {
return credentials.NewCredentials(&credentials.ChainProvider{
VerboseErrors: aws.BoolValue(cfg.CredentialsChainVerboseErrors),
Providers: []credentials.Provider{
&credentials.EnvProvider{},
&credentials.SharedCredentialsProvider{Filename: "", Profile: ""},
RemoteCredProvider(*cfg, handlers),
},
})
}
// RemoteCredProvider returns a credenitials provider for the default remote
// endpoints such as EC2 or ECS Roles.
func RemoteCredProvider(cfg aws.Config, handlers request.Handlers) credentials.Provider {
ecsCredURI := os.Getenv("AWS_CONTAINER_CREDENTIALS_RELATIVE_URI")
if len(ecsCredURI) > 0 {
return ecsCredProvider(cfg, handlers, ecsCredURI)
}
return ec2RoleProvider(cfg, handlers)
}
func ecsCredProvider(cfg aws.Config, handlers request.Handlers, uri string) credentials.Provider {
const host = `169.254.170.2`
return endpointcreds.NewProviderClient(cfg, handlers,
fmt.Sprintf("http://%s%s", host, uri),
func(p *endpointcreds.Provider) {
p.ExpiryWindow = 5 * time.Minute
},
)
}
func ec2RoleProvider(cfg aws.Config, handlers request.Handlers) credentials.Provider {
resolver := cfg.EndpointResolver
if resolver == nil {
resolver = endpoints.DefaultResolver()
}
e, _ := resolver.EndpointFor(endpoints.Ec2metadataServiceID, "")
return &ec2rolecreds.EC2RoleProvider{
Client: ec2metadata.NewClient(cfg, handlers, e.URL, e.SigningRegion),
ExpiryWindow: 5 * time.Minute,
}
}
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