gotosocial/vendor/github.com/godbus/dbus/v5/conn_other.go
Daniele Sluijters acc333c40b
[feature] Inherit resource limits from cgroups (#1336)
When GTS is running in a container runtime which has configured CPU or
memory limits or under an init system that uses cgroups to impose CPU
and memory limits the values the Go runtime sees for GOMAXPROCS and
GOMEMLIMIT are still based on the host resources, not the cgroup.

At least for the throttling middlewares which use GOMAXPROCS to
configure their queue size, this can result in GTS running with values
too big compared to the resources that will actuall be available to it.

This introduces 2 dependencies which can pick up resource contraints
from the current cgroup and tune the Go runtime accordingly. This should
result in the different queues being appropriately sized and in general
more predictable performance. These dependencies are a no-op on
non-Linux systems or if running in a cgroup that doesn't set a limit on
CPU or memory.

The automatic tuning of GOMEMLIMIT can be disabled by either explicitly
setting GOMEMLIMIT yourself or by setting AUTOMEMLIMIT=off. The
automatic tuning of GOMAXPROCS can similarly be counteracted by setting
GOMAXPROCS yourself.
2023-01-17 20:59:04 +00:00

93 lines
2.5 KiB
Go

// +build !darwin
package dbus
import (
"bytes"
"errors"
"fmt"
"io/ioutil"
"os"
"os/exec"
"os/user"
"path"
"strings"
)
var execCommand = exec.Command
func getSessionBusPlatformAddress() (string, error) {
cmd := execCommand("dbus-launch")
b, err := cmd.CombinedOutput()
if err != nil {
return "", err
}
i := bytes.IndexByte(b, '=')
j := bytes.IndexByte(b, '\n')
if i == -1 || j == -1 || i > j {
return "", errors.New("dbus: couldn't determine address of session bus")
}
env, addr := string(b[0:i]), string(b[i+1:j])
os.Setenv(env, addr)
return addr, nil
}
// tryDiscoverDbusSessionBusAddress tries to discover an existing dbus session
// and return the value of its DBUS_SESSION_BUS_ADDRESS.
// It tries different techniques employed by different operating systems,
// returning the first valid address it finds, or an empty string.
//
// * /run/user/<uid>/bus if this exists, it *is* the bus socket. present on
// Ubuntu 18.04
// * /run/user/<uid>/dbus-session: if this exists, it can be parsed for the bus
// address. present on Ubuntu 16.04
//
// See https://dbus.freedesktop.org/doc/dbus-launch.1.html
func tryDiscoverDbusSessionBusAddress() string {
if runtimeDirectory, err := getRuntimeDirectory(); err == nil {
if runUserBusFile := path.Join(runtimeDirectory, "bus"); fileExists(runUserBusFile) {
// if /run/user/<uid>/bus exists, that file itself
// *is* the unix socket, so return its path
return fmt.Sprintf("unix:path=%s", runUserBusFile)
}
if runUserSessionDbusFile := path.Join(runtimeDirectory, "dbus-session"); fileExists(runUserSessionDbusFile) {
// if /run/user/<uid>/dbus-session exists, it's a
// text file // containing the address of the socket, e.g.:
// DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-E1c73yNqrG
if f, err := ioutil.ReadFile(runUserSessionDbusFile); err == nil {
fileContent := string(f)
prefix := "DBUS_SESSION_BUS_ADDRESS="
if strings.HasPrefix(fileContent, prefix) {
address := strings.TrimRight(strings.TrimPrefix(fileContent, prefix), "\n\r")
return address
}
}
}
}
return ""
}
func getRuntimeDirectory() (string, error) {
if currentUser, err := user.Current(); err != nil {
return "", err
} else {
return fmt.Sprintf("/run/user/%s", currentUser.Uid), nil
}
}
func fileExists(filename string) bool {
if _, err := os.Stat(filename); !os.IsNotExist(err) {
return true
} else {
return false
}
}