s3 cache client-side support

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/aws/aws-sdk-go-v2/aws/retryer.go

@@ -0,0 +1,127 @@
+package aws
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+// RetryMode provides the mode the API client will use to create a retryer
+// based on.
+type RetryMode string
+
+const (
+	// RetryModeStandard model provides rate limited retry attempts with
+	// exponential backoff delay.
+	RetryModeStandard RetryMode = "standard"
+
+	// RetryModeAdaptive model provides attempt send rate limiting on throttle
+	// responses in addition to standard mode's retry rate limiting.
+	//
+	// Adaptive retry mode is experimental and is subject to change in the
+	// future.
+	RetryModeAdaptive RetryMode = "adaptive"
+)
+
+// ParseRetryMode attempts to parse a RetryMode from the given string.
+// Returning error if the value is not a known RetryMode.
+func ParseRetryMode(v string) (mode RetryMode, err error) {
+	switch v {
+	case "standard":
+		return RetryModeStandard, nil
+	case "adaptive":
+		return RetryModeAdaptive, nil
+	default:
+		return mode, fmt.Errorf("unknown RetryMode, %v", v)
+	}
+}
+
+func (m RetryMode) String() string { return string(m) }
+
+// Retryer is an interface to determine if a given error from a
+// attempt should be retried, and if so what backoff delay to apply. The
+// default implementation used by most services is the retry package's Standard
+// type. Which contains basic retry logic using exponential backoff.
+type Retryer interface {
+	// IsErrorRetryable returns if the failed attempt is retryable. This check
+	// should determine if the error can be retried, or if the error is
+	// terminal.
+	IsErrorRetryable(error) bool
+
+	// MaxAttempts returns the maximum number of attempts that can be made for
+	// a attempt before failing. A value of 0 implies that the attempt should
+	// be retried until it succeeds if the errors are retryable.
+	MaxAttempts() int
+
+	// RetryDelay returns the delay that should be used before retrying the
+	// attempt. Will return error if the if the delay could not be determined.
+	RetryDelay(attempt int, opErr error) (time.Duration, error)
+
+	// GetRetryToken attempts to deduct the retry cost from the retry token pool.
+	// Returning the token release function, or error.
+	GetRetryToken(ctx context.Context, opErr error) (releaseToken func(error) error, err error)
+
+	// GetInitialToken returns the initial attempt token that can increment the
+	// retry token pool if the attempt is successful.
+	GetInitialToken() (releaseToken func(error) error)
+}
+
+// RetryerV2 is an interface to determine if a given error from a attempt
+// should be retried, and if so what backoff delay to apply. The default
+// implementation used by most services is the retry package's Standard type.
+// Which contains basic retry logic using exponential backoff.
+//
+// RetryerV2 replaces the Retryer interface, deprecating the GetInitialToken
+// method in favor of GetAttemptToken which takes a context, and can return an error.
+//
+// The SDK's retry package's Attempt middleware, and utilities will always
+// wrap a Retryer as a RetryerV2. Delegating to GetInitialToken, only if
+// GetAttemptToken is not implemented.
+type RetryerV2 interface {
+	Retryer
+
+	// GetInitialToken returns the initial attempt token that can increment the
+	// retry token pool if the attempt is successful.
+	//
+	// Deprecated: This method does not provide a way to block using Context,
+	// nor can it return an error. Use RetryerV2, and GetAttemptToken instead.
+	GetInitialToken() (releaseToken func(error) error)
+
+	// GetAttemptToken returns the send token that can be used to rate limit
+	// attempt calls. Will be used by the SDK's retry package's Attempt
+	// middleware to get a send token prior to calling the temp and releasing
+	// the send token after the attempt has been made.
+	GetAttemptToken(context.Context) (func(error) error, error)
+}
+
+// NopRetryer provides a RequestRetryDecider implementation that will flag
+// all attempt errors as not retryable, with a max attempts of 1.
+type NopRetryer struct{}
+
+// IsErrorRetryable returns false for all error values.
+func (NopRetryer) IsErrorRetryable(error) bool { return false }
+
+// MaxAttempts always returns 1 for the original attempt.
+func (NopRetryer) MaxAttempts() int { return 1 }
+
+// RetryDelay is not valid for the NopRetryer. Will always return error.
+func (NopRetryer) RetryDelay(int, error) (time.Duration, error) {
+	return 0, fmt.Errorf("not retrying any attempt errors")
+}
+
+// GetRetryToken returns a stub function that does nothing.
+func (NopRetryer) GetRetryToken(context.Context, error) (func(error) error, error) {
+	return nopReleaseToken, nil
+}
+
+// GetInitialToken returns a stub function that does nothing.
+func (NopRetryer) GetInitialToken() func(error) error {
+	return nopReleaseToken
+}
+
+// GetAttemptToken returns a stub function that does nothing.
+func (NopRetryer) GetAttemptToken(context.Context) (func(error) error, error) {
+	return nopReleaseToken, nil
+}
+
+func nopReleaseToken(error) error { return nil }