prometheus/testutil/directory.go
Chris Marchbanks b40cc43958 Provide option to compress WAL records (#609)
In running Prometheus instances, compressing the records was shown to
reduce disk usage by half while incurring a negligible CPU cost.

Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
2019-06-19 16:46:24 +03:00

146 lines
3.3 KiB
Go

// Copyright 2013 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 testutil
import (
"io/ioutil"
"os"
"path/filepath"
)
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.
NilCloser = nilCloser(true)
// The number of times that a TemporaryDirectory will retry its removal
temporaryDirectoryRemoveRetries = 2
)
type (
// Closer is the interface that wraps the Close method.
Closer interface {
// Close reaps the underlying directory and its children. The directory
// could be deleted by its users already.
Close()
}
nilCloser bool
// TemporaryDirectory models a closeable path for transient POSIX disk
// activities.
TemporaryDirectory interface {
Closer
// Path returns the underlying path for access.
Path() string
}
// 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
// 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{})
}
)
func (c nilCloser) Close() {
}
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,
}
}
func (t temporaryDirectory) Close() {
retries := temporaryDirectoryRemoveRetries
err := os.RemoveAll(t.path)
for err != nil && retries > 0 {
switch {
case os.IsNotExist(err):
err = nil
default:
retries--
err = os.RemoveAll(t.path)
}
}
if err != nil {
t.tester.Fatal(err)
}
}
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) {
var (
directory string
err error
)
directory, err = ioutil.TempDir(defaultDirectory, name)
if err != nil {
t.Fatal(err)
}
handler = temporaryDirectory{
path: directory,
tester: t,
}
return
}
// DirSize returns the size in bytes of all files in a directory.
func DirSize(path string) (int64, error) {
var size int64
err := filepath.Walk(path, func(_ string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if !info.IsDir() {
size += info.Size()
}
return nil
})
return size, err
}