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feat(agent): Handle signals and shutdown gracefully #5914

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Merged
merged 2 commits into from
Jan 30, 2023
Merged

feat(agent): Handle signals and shutdown gracefully #5914

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c083608
feat(agent): Handle signals and shutdown gracefully
mafredri Jan 30, 2023
e125637
fixup! feat(agent): Handle signals and shutdown gracefully
mafredri Jan 30, 2023
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41 changes: 31 additions & 10 deletions cli/agent.go
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ import (
"net/http/pprof"
"net/url"
"os"
"os/signal"
"path/filepath"
"runtime"
"time"
Expand Down Expand Up @@ -35,12 +36,10 @@ func workspaceAgent() *cobra.Command {
Use: "agent",
// This command isn't useful to manually execute.
Hidden: true,
RunE: func(cmd *cobra.Command, args []string) error {
RunE: func(cmd *cobra.Command, _ []string) error {
ctx, cancel := context.WithCancel(cmd.Context())
defer cancel()

go dumpHandler(ctx)

rawURL, err := cmd.Flags().GetString(varAgentURL)
if err != nil {
return xerrors.Errorf("CODER_AGENT_URL must be set: %w", err)
Expand All @@ -50,18 +49,18 @@ func workspaceAgent() *cobra.Command {
return xerrors.Errorf("parse %q: %w", rawURL, err)
}

logWriter := &lumberjack.Logger{
Filename: filepath.Join(os.TempDir(), "coder-agent.log"),
MaxSize: 5, // MB
}
defer logWriter.Close()
logger := slog.Make(sloghuman.Sink(cmd.ErrOrStderr()), sloghuman.Sink(logWriter)).Leveled(slog.LevelDebug)

isLinux := runtime.GOOS == "linux"

// Spawn a reaper so that we don't accumulate a ton
// of zombie processes.
if reaper.IsInitProcess() && !noReap && isLinux {
logWriter := &lumberjack.Logger{
Filename: filepath.Join(os.TempDir(), "coder-agent-init.log"),
MaxSize: 5, // MB
}
defer logWriter.Close()
logger := slog.Make(sloghuman.Sink(cmd.ErrOrStderr()), sloghuman.Sink(logWriter)).Leveled(slog.LevelDebug)
Comment on lines +57 to +62
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@mafredri mafredri Jan 30, 2023 •
edited
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This change might not actually be needed, but it feels safer than having both PID 1 and the forked process share an opened file.


logger.Info(ctx, "spawning reaper process")
// Do not start a reaper on the child process. It's important
// to do this else we fork bomb ourselves.
Expand All @@ -76,6 +75,28 @@ func workspaceAgent() *cobra.Command {
return nil
}

// Handle interrupt signals to allow for graceful shutdown,
// note that calling stopNotify disables the signal handler
// and the next interrupt will terminate the program (you
// probably want cancel instead).
//
// Note that we don't want to handle these signals in the
// process that runs as PID 1, that's why we do this after
// the reaper forked.
ctx, stopNotify := signal.NotifyContext(ctx, InterruptSignals...)
defer stopNotify()

// dumpHandler does signal handling, so we call it after the
// reaper.
go dumpHandler(ctx)

logWriter := &lumberjack.Logger{
Filename: filepath.Join(os.TempDir(), "coder-agent.log"),
MaxSize: 5, // MB
}
defer logWriter.Close()
logger := slog.Make(sloghuman.Sink(cmd.ErrOrStderr()), sloghuman.Sink(logWriter)).Leveled(slog.LevelDebug)

version := buildinfo.Version()
logger.Info(ctx, "starting agent",
slog.F("url", coderURL),
Expand Down