Return idiomatic generic error instead of awserr.Error interface.

Instead of returning an awserr.Error interface the SDK now returns the generic error interface.
This addresses issues where using the SDK would complicate other non-SDK function calls which also
returned errors.

In order to retrieve the Code, Message, and Original Error the returned error will need to be cast to
an awserr inteface. To only retrieve the base generic information you can cast to awserr.Error which will
provide access to the Code, Message and OrigErr.  In order to retrieve more specific information such
as for request failures (awserr.RequestFailure) you can cast to more specific interface types. The
specific error interface types all supersets of the base awserr.Error.

Example Usage:
    resp, err := s3Svc.ListBuckets(&s3.ListBucketsInput{})

    if awsErr, ok := err.(awserr.Error); ok {
        // Generic AWS Error with Code, Message, and original error (if any)
        fmt.Println(awsErr.Code(), awsErr.Message(), awsErr.OrigErr())
        if reqErr, ok := err.(awserr.RequestFailure); ok {
            // A service error occurred
            fmt.Println(reqErr.StatusCode(), reqErr.RequestID())
        }
    } else {
        fmt.Println(err.Error())
    }

Fixes #238

aws/credentials/chain_provider.go

@@ -1,7 +1,6 @@
 package credentials
 
 import (
-	"github.com/awslabs/aws-sdk-go/aws/awserr"
 	"github.com/awslabs/aws-sdk-go/internal/apierr"
 )
 
@@ -57,7 +56,7 @@ func NewChainCredentials(providers []Provider) *Credentials {
 //
 // If a provider is found it will be cached and any calls to IsExpired()
 // will return the expired state of the cached provider.
-func (c *ChainProvider) Retrieve() (Value, awserr.Error) {
+func (c *ChainProvider) Retrieve() (Value, error) {
 	for _, p := range c.Providers {
 		if creds, err := p.Retrieve(); err == nil {
 			c.curr = p

aws/credentials/credentials.go

@@ -49,7 +49,6 @@
 package credentials
 
 import (
-	"github.com/awslabs/aws-sdk-go/aws/awserr"
 	"sync"
 	"time"
 )
@@ -87,7 +86,7 @@ type Value struct {
 type Provider interface {
 	// Refresh returns nil if it successfully retrieved the value.
 	// Error is returned if the value were not obtainable, or empty.
-	Retrieve() (Value, awserr.Error)
+	Retrieve() (Value, error)
 
 	// IsExpired returns if the credentials are no longer valid, and need
 	// to be retrieved.
@@ -130,7 +129,7 @@ func NewCredentials(provider Provider) *Credentials {
 //
 // If Credentials.Expire() was called the credentials Value will be force
 // expired, and the next call to Get() will cause them to be refreshed.
-func (c *Credentials) Get() (Value, awserr.Error) {
+func (c *Credentials) Get() (Value, error) {
 	c.m.Lock()
 	defer c.m.Unlock()
 

aws/credentials/credentials_test.go

@@ -10,10 +10,10 @@ import (
 type stubProvider struct {
 	creds   Value
 	expired bool
-	err     awserr.Error
+	err     error
 }
 
-func (s *stubProvider) Retrieve() (Value, awserr.Error) {
+func (s *stubProvider) Retrieve() (Value, error) {
 	s.expired = false
 	return s.creds, s.err
 }
@@ -42,7 +42,7 @@ func TestCredentialsGetWithError(t *testing.T) {
 	c := NewCredentials(&stubProvider{err: apierr.New("provider error", "", nil), expired: true})
 
 	_, err := c.Get()
-	assert.Equal(t, "provider error", err.Code(), "Expected provider error")
+	assert.Equal(t, "provider error", err.(awserr.Error).Code(), "Expected provider error")
 }
 
 func TestCredentialsExpire(t *testing.T) {

aws/credentials/ec2_role_provider.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"encoding/json"
 	"fmt"
-	"github.com/awslabs/aws-sdk-go/aws/awserr"
 	"github.com/awslabs/aws-sdk-go/internal/apierr"
 	"net/http"
 	"time"
@@ -77,7 +76,7 @@ func NewEC2RoleCredentials(client *http.Client, endpoint string, window time.Dur
 // Retrieve retrieves credentials from the EC2 service.
 // Error will be returned if the request fails, or unable to extract
 // the desired credentials.
-func (m *EC2RoleProvider) Retrieve() (Value, awserr.Error) {
+func (m *EC2RoleProvider) Retrieve() (Value, error) {
 	if m.Client == nil {
 		m.Client = http.DefaultClient
 	}
@@ -129,7 +128,7 @@ type ec2RoleCredRespBody struct {
 
 // 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 *http.Client, endpoint string) ([]string, awserr.Error) {
+func requestCredList(client *http.Client, endpoint string) ([]string, error) {
 	resp, err := client.Get(endpoint)
 	if err != nil {
 		return nil, apierr.New("ListEC2Role", "failed to list EC2 Roles", err)
@@ -153,7 +152,7 @@ func requestCredList(client *http.Client, endpoint string) ([]string, awserr.Err
 //
 // If the credentials cannot be found, or there is an error reading the response
 // and error will be returned.
-func requestCred(client *http.Client, endpoint, credsName string) (*ec2RoleCredRespBody, awserr.Error) {
+func requestCred(client *http.Client, endpoint, credsName string) (*ec2RoleCredRespBody, error) {
 	resp, err := client.Get(endpoint + credsName)
 	if err != nil {
 		return nil, apierr.New("GetEC2RoleCredentials",

aws/credentials/env_provider.go

@@ -1,7 +1,6 @@
 package credentials
 
 import (
-	"github.com/awslabs/aws-sdk-go/aws/awserr"
 	"github.com/awslabs/aws-sdk-go/internal/apierr"
 	"os"
 )
@@ -32,7 +31,7 @@ func NewEnvCredentials() *Credentials {
 }
 
 // Retrieve retrieves the keys from the environment.
-func (e *EnvProvider) Retrieve() (Value, awserr.Error) {
+func (e *EnvProvider) Retrieve() (Value, error) {
 	e.retrieved = false
 
 	id := os.Getenv("AWS_ACCESS_KEY_ID")

aws/credentials/shared_credentials_provider.go

@@ -7,7 +7,6 @@ import (
 
 	"github.com/vaughan0/go-ini"
 
-	"github.com/awslabs/aws-sdk-go/aws/awserr"
 	"github.com/awslabs/aws-sdk-go/internal/apierr"
 )
 
@@ -45,7 +44,7 @@ func NewSharedCredentials(filename, profile string) *Credentials {
 
 // Retrieve reads and extracts the shared credentials from the current
 // users home directory.
-func (p *SharedCredentialsProvider) Retrieve() (Value, awserr.Error) {
+func (p *SharedCredentialsProvider) Retrieve() (Value, error) {
 	p.retrieved = false
 
 	filename, err := p.filename()
@@ -70,7 +69,7 @@ func (p *SharedCredentialsProvider) IsExpired() bool {
 // loadProfiles loads from the file pointed to by shared credentials filename for profile.
 // The credentials retrieved from the profile will be returned or error. Error will be
 // returned if it fails to read from the file, or the data is invalid.
-func loadProfile(filename, profile string) (Value, awserr.Error) {
+func loadProfile(filename, profile string) (Value, error) {
 	config, err := ini.LoadFile(filename)
 	if err != nil {
 		return Value{}, apierr.New("SharedCredsLoad", "failed to load shared credentials file", err)
@@ -103,7 +102,7 @@ func loadProfile(filename, profile string) (Value, awserr.Error) {
 // filename returns the filename to use to read AWS shared credentials.
 //
 // Will return an error if the user's home directory path cannot be found.
-func (p *SharedCredentialsProvider) filename() (string, awserr.Error) {
+func (p *SharedCredentialsProvider) filename() (string, error) {
 	if p.Filename == "" {
 		homeDir := os.Getenv("HOME") // *nix
 		if homeDir == "" {           // Windows

aws/credentials/static_provider.go

@@ -1,7 +1,6 @@
 package credentials
 
 import (
-	"github.com/awslabs/aws-sdk-go/aws/awserr"
 	"github.com/awslabs/aws-sdk-go/internal/apierr"
 )
 
@@ -27,7 +26,7 @@ func NewStaticCredentials(id, secret, token string) *Credentials {
 }
 
 // Retrieve returns the credentials or error if the credentials are invalid.
-func (s *StaticProvider) Retrieve() (Value, awserr.Error) {
+func (s *StaticProvider) Retrieve() (Value, error) {
 	if s.AccessKeyID == "" || s.SecretAccessKey == "" {
 		return Value{}, ErrStaticCredentialsEmpty
 	}

aws/handler_functions.go

@@ -3,7 +3,6 @@ package aws
 import (
 	"bytes"
 	"fmt"
-	"github.com/awslabs/aws-sdk-go/aws/awserr"
 	"github.com/awslabs/aws-sdk-go/internal/apierr"
 	"io"
 	"io/ioutil"
@@ -12,6 +11,7 @@ import (
 	"regexp"
 	"strconv"
 	"time"
+	"github.com/awslabs/aws-sdk-go/aws/awserr"
 )
 
 var sleepDelay = func(delay time.Duration) {
@@ -108,10 +108,12 @@ func AfterRetryHandler(r *Request) {
 		// when the expired token exception occurs the credentials
 		// need to be expired locally so that the next request to
 		// get credentials will trigger a credentials refresh.
-		if r.Error != nil && r.Error.Code() == "ExpiredTokenException" {
-			r.Config.Credentials.Expire()
-			// The credentials will need to be resigned with new credentials
-			r.signed = false
+		if r.Error != nil {
+			if err, ok := r.Error.(awserr.Error); ok && err.Code() == "ExpiredTokenException" {
+				r.Config.Credentials.Expire()
+				// The credentials will need to be resigned with new credentials
+				r.signed = false
+			}
 		}
 
 		r.RetryCount++
@@ -122,11 +124,11 @@ func AfterRetryHandler(r *Request) {
 var (
 	// ErrMissingRegion is an error that is returned if region configuration is
 	// not found.
-	ErrMissingRegion awserr.Error = apierr.New("MissingRegion", "could not find region configuration", nil)
+	ErrMissingRegion error = apierr.New("MissingRegion", "could not find region configuration", nil)
 
 	// ErrMissingEndpoint is an error that is returned if an endpoint cannot be
 	// resolved for a service.
-	ErrMissingEndpoint awserr.Error = apierr.New("MissingEndpoint", "'Endpoint' configuration is required for this service", nil)
+	ErrMissingEndpoint error = apierr.New("MissingEndpoint", "'Endpoint' configuration is required for this service", nil)
 )
 
 // ValidateEndpointHandler is a request handler to validate a request had the

aws/handler_functions_test.go

@@ -5,7 +5,6 @@ import (
 	"os"
 	"testing"
 
-	"github.com/awslabs/aws-sdk-go/aws/awserr"
 	"github.com/awslabs/aws-sdk-go/aws/credentials"
 	"github.com/awslabs/aws-sdk-go/internal/apierr"
 	"github.com/stretchr/testify/assert"
@@ -41,7 +40,7 @@ type mockCredsProvider struct {
 	retreiveCalled bool
 }
 
-func (m *mockCredsProvider) Retrieve() (credentials.Value, awserr.Error) {
+func (m *mockCredsProvider) Retrieve() (credentials.Value, error) {
 	m.retreiveCalled = true
 	return credentials.Value{}, nil
 }

aws/param_validator_test.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/awslabs/aws-sdk-go/aws"
 	"github.com/stretchr/testify/assert"
+	"github.com/awslabs/aws-sdk-go/aws/awserr"
 )
 
 var service = func() *aws.Service {
@@ -58,8 +59,8 @@ func TestMissingRequiredParameters(t *testing.T) {
 	aws.ValidateParameters(req)
 
 	assert.Error(t, req.Error)
-	assert.Equal(t, "InvalidParameter", req.Error.Code())
-	assert.Equal(t, "3 validation errors:\n- missing required parameter: RequiredList\n- missing required parameter: RequiredMap\n- missing required parameter: RequiredBool", req.Error.Message())
+	assert.Equal(t, "InvalidParameter", req.Error.(awserr.Error).Code())
+	assert.Equal(t, "3 validation errors:\n- missing required parameter: RequiredList\n- missing required parameter: RequiredMap\n- missing required parameter: RequiredBool", req.Error.(awserr.Error).Message())
 }
 
 func TestNestedMissingRequiredParameters(t *testing.T) {
@@ -77,7 +78,7 @@ func TestNestedMissingRequiredParameters(t *testing.T) {
 	aws.ValidateParameters(req)
 
 	assert.Error(t, req.Error)
-	assert.Equal(t, "InvalidParameter", req.Error.Code())
-	assert.Equal(t, "3 validation errors:\n- missing required parameter: RequiredList[0].Name\n- missing required parameter: RequiredMap[\"key2\"].Name\n- missing required parameter: OptionalStruct.Name", req.Error.Message())
+	assert.Equal(t, "InvalidParameter", req.Error.(awserr.Error).Code())
+	assert.Equal(t, "3 validation errors:\n- missing required parameter: RequiredList[0].Name\n- missing required parameter: RequiredMap[\"key2\"].Name\n- missing required parameter: OptionalStruct.Name", req.Error.(awserr.Error).Message())
 
 }

aws/request.go

@@ -2,7 +2,6 @@ package aws
 
 import (
 	"bytes"
-	"github.com/awslabs/aws-sdk-go/aws/awserr"
 	"io"
 	"io/ioutil"
 	"net/http"
@@ -24,7 +23,7 @@ type Request struct {
 	Body         io.ReadSeeker
 	bodyStart    int64 // offset from beginning of Body that the request body starts
 	Params       interface{}
-	Error        awserr.Error
+	Error        error
 	Data         interface{}
 	RequestID    string
 	RetryCount   uint
@@ -116,7 +115,7 @@ func (r *Request) SetReaderBody(reader io.ReadSeeker) {
 
 // Presign returns the request's signed URL. Error will be returned
 // if the signing fails.
-func (r *Request) Presign(expireTime time.Duration) (string, awserr.Error) {
+func (r *Request) Presign(expireTime time.Duration) (string, error) {
 	r.ExpireTime = expireTime
 	r.Sign()
 	if r.Error != nil {
@@ -135,7 +134,7 @@ func (r *Request) Presign(expireTime time.Duration) (string, awserr.Error) {
 //
 // If any Validate or Build errors occur the build will stop and the error
 // which occurred will be returned.
-func (r *Request) Build() awserr.Error {
+func (r *Request) Build() error {
 	if !r.built {
 		r.Error = nil
 		r.Handlers.Validate.Run(r)
@@ -153,7 +152,7 @@ func (r *Request) Build() awserr.Error {
 //
 // Send will build the request prior to signing. All Sign Handlers will
 // be executed in the order they were set.
-func (r *Request) Sign() awserr.Error {
+func (r *Request) Sign() error {
 	if r.signed {
 		return r.Error
 	}
@@ -172,7 +171,7 @@ func (r *Request) Sign() awserr.Error {
 //
 // Send will sign the request prior to sending. All Send Handlers will
 // be executed in the order they were set.
-func (r *Request) Send() awserr.Error {
+func (r *Request) Send() error {
 	for {
 		r.Sign()
 		if r.Error != nil {

aws/request_test.go

@@ -135,8 +135,8 @@ func TestRequest4xxUnretryable(t *testing.T) {
 	} else {
 		assert.Fail(t, "Expected error to be a service failure")
 	}
-	assert.Equal(t, "SignatureDoesNotMatch", err.Code())
-	assert.Equal(t, "Signature does not match.", err.Message())
+	assert.Equal(t, "SignatureDoesNotMatch", err.(awserr.Error).Code())
+	assert.Equal(t, "Signature does not match.", err.(awserr.Error).Message())
 	assert.Equal(t, 0, int(r.RetryCount))
 }
 
@@ -171,8 +171,8 @@ func TestRequestExhaustRetries(t *testing.T) {
 	} else {
 		assert.Fail(t, "Expected error to be a service failure")
 	}
-	assert.Equal(t, "UnknownError", err.Code())
-	assert.Equal(t, "An error occurred.", err.Message())
+	assert.Equal(t, "UnknownError", err.(awserr.Error).Code())
+	assert.Equal(t, "An error occurred.", err.(awserr.Error).Message())
 	assert.Equal(t, 3, int(r.RetryCount))
 	assert.True(t, reflect.DeepEqual([]time.Duration{30 * time.Millisecond, 60 * time.Millisecond, 120 * time.Millisecond}, delays))
 }
@@ -194,7 +194,7 @@ func TestRequestRecoverExpiredCreds(t *testing.T) {
 	credExpiredAfterRetry := false
 
 	s.Handlers.Retry.PushBack(func(r *Request) {
-		if r.Error != nil && r.Error.Code() == "ExpiredTokenException" {
+		if r.Error != nil && r.Error.(awserr.Error).Code() == "ExpiredTokenException" {
 			credExpiredBeforeRetry = r.Config.Credentials.IsExpired()
 		}
 	})

aws/service.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/awslabs/aws-sdk-go/internal/endpoints"
+	"github.com/awslabs/aws-sdk-go/aws/awserr"
 )
 
 // A Service implements the base service request and response handling
@@ -146,8 +147,10 @@ func shouldRetry(r *Request) bool {
 		return true
 	}
 	if r.Error != nil {
-		if _, ok := retryableCodes[r.Error.Code()]; ok {
-			return true
+		if err, ok := r.Error.(awserr.Error); ok {
+			if _, ok := retryableCodes[err.Code()]; ok {
+				return true
+			}
 		}
 	}
 	return false

internal/fixtures/protocol/generate.go

@@ -74,7 +74,6 @@ var extraImports = []string{
 	"net/url",
 	"github.com/awslabs/aws-sdk-go/internal/protocol/xml/xmlutil",
 	"github.com/awslabs/aws-sdk-go/internal/util",
-	"github.com/awslabs/aws-sdk-go/aws/awserr",
 	"github.com/stretchr/testify/assert",
 }
 

internal/model/api/api.go

@@ -199,7 +199,6 @@ var oprw sync.Mutex
 func (a *API) APIGoCode() string {
 	a.resetImports()
 	a.imports["sync"] = true
-	a.imports["github.com/awslabs/aws-sdk-go/aws/awserr"] = true
 	var buf bytes.Buffer
 	err := tplAPI.Execute(&buf, a)
 	if err != nil {
@@ -325,7 +324,6 @@ func (a *API) InterfaceGoCode() string {
 	a.resetImports()
 	a.imports = map[string]bool{
 		"github.com/awslabs/aws-sdk-go/service/" + a.PackageName(): true,
-		"github.com/awslabs/aws-sdk-go/aws/awserr":                 true,
 	}
 
 	var buf bytes.Buffer