rclone/vendor/github.com/spacemonkeygo/monkit/v3/error_names.go
2020-05-12 15:56:50 +00:00

115 lines
3.2 KiB
Go

// Copyright (C) 2017 Space Monkey, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package monkit
import (
"context"
"io"
"net"
"os"
"sync"
"sync/atomic"
)
// errorNameHandlers keeps track of the list of error name handlers monkit will
// call to give errors good metric names.
var errorNameHandlers struct {
write_mu sync.Mutex
value atomic.Value
}
// AddErrorNameHandler adds an error name handler function that will be
// consulted every time an error is captured for a task. The handlers will be
// called in the order they were registered with the most recently added
// handler first, until a handler returns true for the second return value.
// If no handler returns true, the error is checked to see if it implements
// an interface that allows it to name itself, and otherwise, monkit attempts
// to find a good name for most built in Go standard library errors.
func AddErrorNameHandler(f func(error) (string, bool)) {
errorNameHandlers.write_mu.Lock()
defer errorNameHandlers.write_mu.Unlock()
handlers, _ := errorNameHandlers.value.Load().([]func(error) (string, bool))
handlers = append(handlers, f)
errorNameHandlers.value.Store(handlers)
}
// getErrorName implements the logic described in the AddErrorNameHandler
// function.
func getErrorName(err error) string {
// check if any of the handlers will handle it
handlers, _ := errorNameHandlers.value.Load().([]func(error) (string, bool))
for i := len(handlers) - 1; i >= 0; i-- {
if name, ok := handlers[i](err); ok {
return name
}
}
// check if it knows how to name itself
type namer interface {
Name() (string, bool)
}
if n, ok := err.(namer); ok {
if name, ok := n.Name(); ok {
return name
}
}
// check if it's a known error that we handle to give good names
switch err {
case io.EOF:
return "EOF"
case io.ErrUnexpectedEOF:
return "Unexpected EOF Error"
case io.ErrClosedPipe:
return "Closed Pipe Error"
case io.ErrNoProgress:
return "No Progress Error"
case io.ErrShortBuffer:
return "Short Buffer Error"
case io.ErrShortWrite:
return "Short Write Error"
case context.Canceled:
return "Canceled"
case context.DeadlineExceeded:
return "Timeout"
}
if isErrnoError(err) {
return "Errno"
}
switch err.(type) {
case *os.SyscallError:
return "Syscall Error"
case net.UnknownNetworkError:
return "Unknown Network Error"
case *net.AddrError:
return "Addr Error"
case net.InvalidAddrError:
return "Invalid Addr Error"
case *net.OpError:
return "Net Op Error"
case *net.ParseError:
return "Net Parse Error"
case *net.DNSError:
return "DNS Error"
case *net.DNSConfigError:
return "DNS Config Error"
case net.Error:
return "Network Error"
}
return "System Error"
}