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|
package errcode
import (
"fmt"
"net/http"
"sort"
"sync"
)
var (
errorCodeToDescriptors = map[ErrorCode]ErrorDescriptor{}
idToDescriptors = map[string]ErrorDescriptor{}
groupToDescriptors = map[string][]ErrorDescriptor{}
)
var (
// ErrorCodeUnknown is a generic error that can be used as a last
// resort if there is no situation-specific error message that can be used
ErrorCodeUnknown = Register("errcode", ErrorDescriptor{
Value: "UNKNOWN",
Message: "unknown error",
Description: `Generic error returned when the error does not have an
API classification.`,
HTTPStatusCode: http.StatusInternalServerError,
})
// ErrorCodeUnsupported is returned when an operation is not supported.
ErrorCodeUnsupported = Register("errcode", ErrorDescriptor{
Value: "UNSUPPORTED",
Message: "The operation is unsupported.",
Description: `The operation was unsupported due to a missing
implementation or invalid set of parameters.`,
HTTPStatusCode: http.StatusMethodNotAllowed,
})
// ErrorCodeUnauthorized is returned if a request requires
// authentication.
ErrorCodeUnauthorized = Register("errcode", ErrorDescriptor{
Value: "UNAUTHORIZED",
Message: "authentication required",
Description: `The access controller was unable to authenticate
the client. Often this will be accompanied by a
Www-Authenticate HTTP response header indicating how to
authenticate.`,
HTTPStatusCode: http.StatusUnauthorized,
})
// ErrorCodeDenied is returned if a client does not have sufficient
// permission to perform an action.
ErrorCodeDenied = Register("errcode", ErrorDescriptor{
Value: "DENIED",
Message: "requested access to the resource is denied",
Description: `The access controller denied access for the
operation on a resource.`,
HTTPStatusCode: http.StatusForbidden,
})
// ErrorCodeUnavailable provides a common error to report unavailability
// of a service or endpoint.
ErrorCodeUnavailable = Register("errcode", ErrorDescriptor{
Value: "UNAVAILABLE",
Message: "service unavailable",
Description: "Returned when a service is not available",
HTTPStatusCode: http.StatusServiceUnavailable,
})
// ErrorCodeTooManyRequests is returned if a client attempts too many
// times to contact a service endpoint.
ErrorCodeTooManyRequests = Register("errcode", ErrorDescriptor{
Value: "TOOMANYREQUESTS",
Message: "too many requests",
Description: `Returned when a client attempts to contact a
service too many times`,
HTTPStatusCode: http.StatusTooManyRequests,
})
)
var nextCode = 1000
var registerLock sync.Mutex
// Register will make the passed-in error known to the environment and
// return a new ErrorCode
func Register(group string, descriptor ErrorDescriptor) ErrorCode {
registerLock.Lock()
defer registerLock.Unlock()
descriptor.Code = ErrorCode(nextCode)
if _, ok := idToDescriptors[descriptor.Value]; ok {
panic(fmt.Sprintf("ErrorValue %q is already registered", descriptor.Value))
}
if _, ok := errorCodeToDescriptors[descriptor.Code]; ok {
panic(fmt.Sprintf("ErrorCode %v is already registered", descriptor.Code))
}
groupToDescriptors[group] = append(groupToDescriptors[group], descriptor)
errorCodeToDescriptors[descriptor.Code] = descriptor
idToDescriptors[descriptor.Value] = descriptor
nextCode++
return descriptor.Code
}
type byValue []ErrorDescriptor
func (a byValue) Len() int { return len(a) }
func (a byValue) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a byValue) Less(i, j int) bool { return a[i].Value < a[j].Value }
// GetGroupNames returns the list of Error group names that are registered
func GetGroupNames() []string {
keys := []string{}
for k := range groupToDescriptors {
keys = append(keys, k)
}
sort.Strings(keys)
return keys
}
// GetErrorCodeGroup returns the named group of error descriptors
func GetErrorCodeGroup(name string) []ErrorDescriptor {
desc := groupToDescriptors[name]
sort.Sort(byValue(desc))
return desc
}
// GetErrorAllDescriptors returns a slice of all ErrorDescriptors that are
// registered, irrespective of what group they're in
func GetErrorAllDescriptors() []ErrorDescriptor {
result := []ErrorDescriptor{}
for _, group := range GetGroupNames() {
result = append(result, GetErrorCodeGroup(group)...)
}
sort.Sort(byValue(result))
return result
}
|
