client_golang/internal/errcapture/errcapture.go

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// Copyright 2014 The Prometheus Authors
// 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 errcapture
import (
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"github.com/prometheus/client_golang/prometheus"
)
type doFunc func() error
// Do runs function and on error return error by argument including the given error (usually
// from caller function).
func Do(err *error, doer doFunc, format string, a ...interface{}) {
derr := doer()
if err == nil || derr == nil {
return
}
// For os closers, it's a common case to double close.
// From reliability purpose this is not a problem it may only indicate surprising execution path.
if errors.Is(derr, os.ErrClosed) {
return
}
errs := prometheus.MultiError{}
errs.Append(*err)
errs.Append(fmt.Errorf(format+": %w", append(a, derr)...))
*err = errs
}
// ExhaustClose closes the io.ReadCloser with error capture but exhausts the reader before.
func ExhaustClose(err *error, r io.ReadCloser, format string, a ...interface{}) {
_, copyErr := io.Copy(ioutil.Discard, r)
Do(err, r.Close, format, a...)
if copyErr == nil {
return
}
errs := prometheus.MultiError{}
errs.Append(copyErr)
errs.Append(*err)
*err = errs
}