prometheus/util/testutil/directory.go

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// Copyright 2013 The Prometheus Authors
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// 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.
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package testutil
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import (
"crypto/sha256"
"io"
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"io/ioutil"
"os"
"path/filepath"
"strconv"
"testing"
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)
const (
// The base directory used for test emissions, which instructs the operating
// system to use the default temporary directory as the base or TMPDIR
// environment variable.
defaultDirectory = ""
// NilCloser is a no-op Closer.
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NilCloser = nilCloser(true)
// The number of times that a TemporaryDirectory will retry its removal
temporaryDirectoryRemoveRetries = 2
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)
type (
// Closer is the interface that wraps the Close method.
Closer interface {
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// Close reaps the underlying directory and its children. The directory
// could be deleted by its users already.
Close()
}
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nilCloser bool
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// TemporaryDirectory models a closeable path for transient POSIX disk
// activities.
TemporaryDirectory interface {
Closer
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// Path returns the underlying path for access.
Path() string
}
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// temporaryDirectory is kept as a private type due to private fields and
// their interactions.
temporaryDirectory struct {
path string
tester T
}
callbackCloser struct {
fn func()
}
// T implements the needed methods of testing.TB so that we do not need
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// to actually import testing (which has the side effect of adding all
// the test flags, which we do not want in non-test binaries even if
// they make use of these utilities for some reason).
T interface {
Fatal(args ...interface{})
Fatalf(format string, args ...interface{})
}
)
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func (c nilCloser) Close() {
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}
func (c callbackCloser) Close() {
c.fn()
}
// NewCallbackCloser returns a Closer that calls the provided function upon
// closing.
func NewCallbackCloser(fn func()) Closer {
return &callbackCloser{
fn: fn,
}
}
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func (t temporaryDirectory) Close() {
retries := temporaryDirectoryRemoveRetries
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err := os.RemoveAll(t.path)
for err != nil && retries > 0 {
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switch {
case os.IsNotExist(err):
err = nil
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default:
retries--
err = os.RemoveAll(t.path)
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}
}
if err != nil {
t.tester.Fatal(err)
}
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}
func (t temporaryDirectory) Path() string {
return t.path
}
// NewTemporaryDirectory creates a new temporary directory for transient POSIX
// activities.
func NewTemporaryDirectory(name string, t T) (handler TemporaryDirectory) {
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var (
directory string
err error
)
directory, err = ioutil.TempDir(defaultDirectory, name)
if err != nil {
t.Fatal(err)
}
handler = temporaryDirectory{
path: directory,
tester: t,
}
return
}
// DirHash returns a hash of all files attribites and their content within a directory.
func DirHash(t *testing.T, path string) []byte {
hash := sha256.New()
err := filepath.Walk(path, func(path string, info os.FileInfo, err error) error {
Ok(t, err)
if info.IsDir() {
return nil
}
f, err := os.Open(path)
Ok(t, err)
defer f.Close()
_, err = io.Copy(hash, f)
Ok(t, err)
_, err = io.WriteString(hash, strconv.Itoa(int(info.Size())))
Ok(t, err)
_, err = io.WriteString(hash, info.Name())
Ok(t, err)
modTime, err := info.ModTime().GobEncode()
Ok(t, err)
_, err = io.WriteString(hash, string(modTime))
Ok(t, err)
return nil
})
Ok(t, err)
return hash.Sum(nil)
}