aws/credentials: Add ProviderWithContext optional interface to suppor…

…t passing contexts on credential retrieval (#3223)

CHANGELOG_PENDING.md

@@ -1,5 +1,10 @@
 ### SDK Features
 
 ### SDK Enhancements
+* `aws/credentials`: `ProviderWithContext` optional interface has been added to support passing contexts on credential retrieval ([#3223](https://github.com/aws/aws-sdk-go/pull/3223))
+  * Credential providers that implement the optional `ProviderWithContext` will have context passed to them
+  * `ec2rolecreds.EC2RoleProvider`, `endpointcreds.Provider`, `stscreds.AssumeRoleProvider`, `stscreds.WebIdentityRoleProvider` have been updated to support the `ProviderWithContext` interface
+  * Fixes [#3213](https://github.com/aws/aws-sdk-go/issues/3213)
+* `aws/ec2metadata`: Context aware operations have been added `EC2Metadata` client ([#3223](https://github.com/aws/aws-sdk-go/pull/3223))
 
 ### SDK Bugs

aws/credentials/credentials.go

@@ -107,6 +107,13 @@ type Provider interface {
 	IsExpired() bool
 }
 
+// ProviderWithContext is a Provider that can retrieve credentials with a Context
+type ProviderWithContext interface {
+	Provider
+
+	RetrieveWithContext(Context) (Value, error)
+}
+
 // An Expirer is an interface that Providers can implement to expose the expiration
 // time, if known.  If the Provider cannot accurately provide this info,
 // it should not implement this interface.
@@ -233,7 +240,9 @@ func (c *Credentials) GetWithContext(ctx Context) (Value, error) {
 	// Cannot pass context down to the actual retrieve, because the first
 	// context would cancel the whole group when there is not direct
 	// association of items in the group.
-	resCh := c.sf.DoChan("", c.singleRetrieve)
+	resCh := c.sf.DoChan("", func() (interface{}, error) {
+		return c.singleRetrieve(&suppressedContext{ctx})
+	})
 	select {
 	case res := <-resCh:
 		return res.Val.(Value), res.Err
@@ -243,12 +252,16 @@ func (c *Credentials) GetWithContext(ctx Context) (Value, error) {
 	}
 }
 
-func (c *Credentials) singleRetrieve() (interface{}, error) {
+func (c *Credentials) singleRetrieve(ctx Context) (creds interface{}, err error) {
 	if curCreds := c.creds.Load(); !c.isExpired(curCreds) {
 		return curCreds.(Value), nil
 	}
 
-	creds, err := c.provider.Retrieve()
+	if p, ok := c.provider.(ProviderWithContext); ok {
+		creds, err = p.RetrieveWithContext(ctx)
+	} else {
+		creds, err = c.provider.Retrieve()
+	}
 	if err == nil {
 		c.creds.Store(creds)
 	}
@@ -308,3 +321,19 @@ func (c *Credentials) ExpiresAt() (time.Time, error) {
 	}
 	return expirer.ExpiresAt(), nil
 }
+
+type suppressedContext struct {
+	Context
+}
+
+func (s *suppressedContext) Deadline() (deadline time.Time, ok bool) {
+	return time.Time{}, false
+}
+
+func (s *suppressedContext) Done() <-chan struct{} {
+	return nil
+}
+
+func (s *suppressedContext) Err() error {
+	return nil
+}

aws/credentials/ec2rolecreds/ec2_role_provider.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/aws/client"
 	"github.com/aws/aws-sdk-go/aws/credentials"
@@ -87,7 +88,14 @@ func NewCredentialsWithClient(client *ec2metadata.EC2Metadata, options ...func(*
 // Error will be returned if the request fails, or unable to extract
 // the desired credentials.
 func (m *EC2RoleProvider) Retrieve() (credentials.Value, error) {
-	credsList, err := requestCredList(m.Client)
+	return m.RetrieveWithContext(aws.BackgroundContext())
+}
+
+// RetrieveWithContext retrieves credentials from the EC2 service.
+// Error will be returned if the request fails, or unable to extract
+// the desired credentials.
+func (m *EC2RoleProvider) RetrieveWithContext(ctx credentials.Context) (credentials.Value, error) {
+	credsList, err := requestCredList(ctx, m.Client)
 	if err != nil {
 		return credentials.Value{ProviderName: ProviderName}, err
 	}
@@ -97,7 +105,7 @@ func (m *EC2RoleProvider) Retrieve() (credentials.Value, error) {
 	}
 	credsName := credsList[0]
 
-	roleCreds, err := requestCred(m.Client, credsName)
+	roleCreds, err := requestCred(ctx, m.Client, credsName)
 	if err != nil {
 		return credentials.Value{ProviderName: ProviderName}, err
 	}
@@ -130,8 +138,8 @@ const iamSecurityCredsPath = "iam/security-credentials/"
 
 // requestCredList requests a list of credentials from the EC2 service.
 // If there are no credentials, or there is an error making or receiving the request
-func requestCredList(client *ec2metadata.EC2Metadata) ([]string, error) {
-	resp, err := client.GetMetadata(iamSecurityCredsPath)
+func requestCredList(ctx aws.Context, client *ec2metadata.EC2Metadata) ([]string, error) {
+	resp, err := client.GetMetadataWithContext(ctx, iamSecurityCredsPath)
 	if err != nil {
 		return nil, awserr.New("EC2RoleRequestError", "no EC2 instance role found", err)
 	}
@@ -154,8 +162,8 @@ func requestCredList(client *ec2metadata.EC2Metadata) ([]string, error) {
 //
 // If the credentials cannot be found, or there is an error reading the response
 // and error will be returned.
-func requestCred(client *ec2metadata.EC2Metadata, credsName string) (ec2RoleCredRespBody, error) {
-	resp, err := client.GetMetadata(sdkuri.PathJoin(iamSecurityCredsPath, credsName))
+func requestCred(ctx aws.Context, client *ec2metadata.EC2Metadata, credsName string) (ec2RoleCredRespBody, error) {
+	resp, err := client.GetMetadataWithContext(ctx, sdkuri.PathJoin(iamSecurityCredsPath, credsName))
 	if err != nil {
 		return ec2RoleCredRespBody{},
 			awserr.New("EC2RoleRequestError",

aws/credentials/endpointcreds/provider.go

@@ -116,7 +116,13 @@ func (p *Provider) IsExpired() bool {
 // Retrieve will attempt to request the credentials from the endpoint the Provider
 // was configured for. And error will be returned if the retrieval fails.
 func (p *Provider) Retrieve() (credentials.Value, error) {
-	resp, err := p.getCredentials()
+	return p.RetrieveWithContext(aws.BackgroundContext())
+}
+
+// RetrieveWithContext will attempt to request the credentials from the endpoint the Provider
+// was configured for. And error will be returned if the retrieval fails.
+func (p *Provider) RetrieveWithContext(ctx credentials.Context) (credentials.Value, error) {
+	resp, err := p.getCredentials(ctx)
 	if err != nil {
 		return credentials.Value{ProviderName: ProviderName},
 			awserr.New("CredentialsEndpointError", "failed to load credentials", err)
@@ -148,14 +154,15 @@ type errorOutput struct {
 	Message string `json:"message"`
 }
 
-func (p *Provider) getCredentials() (*getCredentialsOutput, error) {
+func (p *Provider) getCredentials(ctx aws.Context) (*getCredentialsOutput, error) {
 	op := &request.Operation{
 		Name:       "GetCredentials",
 		HTTPMethod: "GET",
 	}
 
 	out := &getCredentialsOutput{}
 	req := p.Client.NewRequest(op, nil, out)
+	req.SetContext(ctx)
 	req.HTTPRequest.Header.Set("Accept", "application/json")
 	if authToken := p.AuthorizationToken; len(authToken) != 0 {
 		req.HTTPRequest.Header.Set("Authorization", authToken)

aws/credentials/stscreds/assume_role_provider.go

@@ -87,6 +87,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/aws/client"
 	"github.com/aws/aws-sdk-go/aws/credentials"
+	"github.com/aws/aws-sdk-go/aws/request"
 	"github.com/aws/aws-sdk-go/internal/sdkrand"
 	"github.com/aws/aws-sdk-go/service/sts"
 )
@@ -118,6 +119,10 @@ type AssumeRoler interface {
 	AssumeRole(input *sts.AssumeRoleInput) (*sts.AssumeRoleOutput, error)
 }
 
+type assumeRolerWithContext interface {
+	AssumeRoleWithContext(aws.Context, *sts.AssumeRoleInput, ...request.Option) (*sts.AssumeRoleOutput, error)
+}
+
 // DefaultDuration is the default amount of time in minutes that the credentials
 // will be valid for.
 var DefaultDuration = time.Duration(15) * time.Minute
@@ -265,6 +270,11 @@ func NewCredentialsWithClient(svc AssumeRoler, roleARN string, options ...func(*
 
 // Retrieve generates a new set of temporary credentials using STS.
 func (p *AssumeRoleProvider) Retrieve() (credentials.Value, error) {
+	return p.RetrieveWithContext(aws.BackgroundContext())
+}
+
+// RetrieveWithContext generates a new set of temporary credentials using STS.
+func (p *AssumeRoleProvider) RetrieveWithContext(ctx credentials.Context) (credentials.Value, error) {
 	// Apply defaults where parameters are not set.
 	if p.RoleSessionName == "" {
 		// Try to work out a role name that will hopefully end up unique.
@@ -304,7 +314,15 @@ func (p *AssumeRoleProvider) Retrieve() (credentials.Value, error) {
 		}
 	}
 
-	roleOutput, err := p.Client.AssumeRole(input)
+	var roleOutput *sts.AssumeRoleOutput
+	var err error
+
+	if c, ok := p.Client.(assumeRolerWithContext); ok {
+		roleOutput, err = c.AssumeRoleWithContext(ctx, input)
+	} else {
+		roleOutput, err = p.Client.AssumeRole(input)
+	}
+
 	if err != nil {
 		return credentials.Value{ProviderName: ProviderName}, err
 	}

aws/credentials/stscreds/assume_role_provider_test.go

@@ -6,6 +6,8 @@ import (
 	"time"
 
 	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/credentials"
+	"github.com/aws/aws-sdk-go/aws/request"
 	"github.com/aws/aws-sdk-go/service/sts"
 )
 
@@ -29,6 +31,16 @@ func (s *stubSTS) AssumeRole(input *sts.AssumeRoleInput) (*sts.AssumeRoleOutput,
 	}, nil
 }
 
+type stubSTSWithContext struct {
+	stubSTS
+	called chan struct{}
+}
+
+func (s *stubSTSWithContext) AssumeRoleWithContext(context credentials.Context, input *sts.AssumeRoleInput, option ...request.Option) (*sts.AssumeRoleOutput, error) {
+	<-s.called
+	return s.stubSTS.AssumeRole(input)
+}
+
 func TestAssumeRoleProvider(t *testing.T) {
 	stub := &stubSTS{}
 	p := &AssumeRoleProvider{
@@ -223,3 +235,32 @@ func TestAssumeRoleProvider_WithTags(t *testing.T) {
 		t.Errorf("expect error")
 	}
 }
+
+func TestAssumeRoleProvider_RetrieveWithContext(t *testing.T) {
+	stub := &stubSTSWithContext{
+		called: make(chan struct{}),
+	}
+	p := &AssumeRoleProvider{
+		Client:  stub,
+		RoleARN: "roleARN",
+	}
+
+	go func() {
+		stub.called <- struct{}{}
+	}()
+
+	creds, err := p.RetrieveWithContext(aws.BackgroundContext())
+	if err != nil {
+		t.Errorf("expect nil, got %v", err)
+	}
+
+	if e, a := "roleARN", creds.AccessKeyID; e != a {
+		t.Errorf("expect %v, got %v", e, a)
+	}
+	if e, a := "assumedSecretAccessKey", creds.SecretAccessKey; e != a {
+		t.Errorf("expect %v, got %v", e, a)
+	}
+	if e, a := "assumedSessionToken", creds.SessionToken; e != a {
+		t.Errorf("expect %v, got %v", e, a)
+	}
+}

aws/credentials/stscreds/web_identity_provider.go

@@ -64,6 +64,13 @@ func NewWebIdentityRoleProvider(svc stsiface.STSAPI, roleARN, roleSessionName, p
 // 'WebIdentityTokenFilePath' specified destination and if that is empty an
 // error will be returned.
 func (p *WebIdentityRoleProvider) Retrieve() (credentials.Value, error) {
+	return p.RetrieveWithContext(aws.BackgroundContext())
+}
+
+// RetrieveWithContext will attempt to assume a role from a token which is located at
+// 'WebIdentityTokenFilePath' specified destination and if that is empty an
+// error will be returned.
+func (p *WebIdentityRoleProvider) RetrieveWithContext(ctx credentials.Context) (credentials.Value, error) {
 	b, err := ioutil.ReadFile(p.tokenFilePath)
 	if err != nil {
 		errMsg := fmt.Sprintf("unable to read file at %s", p.tokenFilePath)
@@ -81,6 +88,9 @@ func (p *WebIdentityRoleProvider) Retrieve() (credentials.Value, error) {
 		RoleSessionName:  &sessionName,
 		WebIdentityToken: aws.String(string(b)),
 	})
+
+	req.SetContext(ctx)
+
 	// InvalidIdentityToken error is a temporary error that can occur
 	// when assuming an Role with a JWT web identity token.
 	req.RetryErrorCodes = append(req.RetryErrorCodes, sts.ErrCodeInvalidIdentityTokenException)