99 lines
3.4 KiB
Go
99 lines
3.4 KiB
Go
// Mgmt
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// Copyright (C) James Shubin and the project contributors
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// Written by James Shubin <james@shubin.ca> and the project contributors
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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//
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// Additional permission under GNU GPL version 3 section 7
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//
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// If you modify this program, or any covered work, by linking or combining it
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// with embedded mcl code and modules (and that the embedded mcl code and
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// modules which link with this program, contain a copy of their source code in
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// the authoritative form) containing parts covered by the terms of any other
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// license, the licensors of this program grant you additional permission to
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// convey the resulting work. Furthermore, the licensors of this program grant
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// the original author, James Shubin, additional permission to update this
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// additional permission if he deems it necessary to achieve the goals of this
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// additional permission.
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// Package pprof is a simple wrapper around the pprof utility code which we use.
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package pprof
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import (
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"context"
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"fmt"
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"log"
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"os"
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"os/signal"
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"runtime/pprof"
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"strings"
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"syscall"
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)
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// Run looks in a special environment var for the path to log pprof data to and
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// if it finds it, it begins profiling. If it doesn't find a special environment
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// var, it returns nil. If this is not able to start logging, then it errors. If
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// it starts logging, this waits for an exit signal in a goroutine and returns
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// nil. The magic env name is MGMT_PPROF_PATH. Example usage:
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// MGMT_PPROF_PATH=~/pprof/"out.pprof" ./mgmt run lang examples/lang/hello0.mcl
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// go tool pprof -no_browser -http :10000 ~/pprof/out.pprof
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func Run(ctx context.Context) error {
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s := os.Getenv("MGMT_PPROF_PATH")
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logf := func(format string, v ...interface{}) {
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// TODO: is this a sane prefix to use here?
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log.Printf(format, v...) // XXX: use parent logger when available
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}
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if s == "" {
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return nil // not activated
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}
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if !strings.HasPrefix(s, "/") {
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return fmt.Errorf("pprof path is not absolute")
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}
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f, err := os.Create(s)
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if err != nil {
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return fmt.Errorf("could not create CPU profile: %v", err)
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}
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if err := pprof.StartCPUProfile(f); err != nil {
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return fmt.Errorf("could not start CPU profile: %v", err)
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}
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logf("pprof logging to: %s", s)
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signals := make(chan os.Signal, 1+1) // 1 * ^C + 1 * SIGTERM
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signal.Notify(signals, os.Interrupt) // catch ^C
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//signal.Notify(signals, os.Kill) // catch signals
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signal.Notify(signals, syscall.SIGTERM)
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go func() {
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defer func() {
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if err := f.Close(); err != nil {
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logf("pprof write error: %v", err)
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return
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}
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logf("pprof wrote file to: %s", s)
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}()
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defer pprof.StopCPUProfile()
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select {
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case sig := <-signals: // any signal will do
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logf("pprof logging shutdown by sig: %v", sig)
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case <-ctx.Done():
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logf("pprof logging shutdown by ctx: %v", ctx.Err())
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}
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}()
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return nil
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}
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