127 lines
3.2 KiB
Go
127 lines
3.2 KiB
Go
// Copyright 2024 Joshua Rich <joshua.rich@gmail.com>.
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// SPDX-License-Identifier: MIT
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package mem
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import (
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"context"
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"fmt"
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"log/slog"
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"net/url"
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"strings"
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"github.com/joshuar/go-hass-agent/internal/hass/event"
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"github.com/joshuar/go-hass-agent/internal/linux"
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"github.com/joshuar/go-hass-agent/internal/logging"
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"github.com/joshuar/go-hass-agent/pkg/linux/dbusx"
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)
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const (
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oomEventsWorkerID = "oom_events_worker"
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oomDBusPath = "/org/freedesktop/systemd1/unit"
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unitPathPrefix = "/org/freedesktop/systemd1/unit"
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oomEventName = "oom_event"
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)
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type oomEventData struct {
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Process string `json:"process"`
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PID int `json:"pid"`
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}
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type OOMEventsWorker struct {
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triggerCh chan dbusx.Trigger
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linux.EventWorker
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}
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//nolint:gocognit
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func (w *OOMEventsWorker) Events(ctx context.Context) (<-chan event.Event, error) {
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eventCh := make(chan event.Event)
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go func() {
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defer close(eventCh)
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for {
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select {
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case <-ctx.Done():
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return
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case trigger := <-w.triggerCh:
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props, err := dbusx.ParsePropertiesChanged(trigger.Content)
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if err != nil {
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logging.FromContext(ctx).Debug("Could not parse changed properties for unit.", slog.Any("error", err))
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continue
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}
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// Ignore events that don't indicate a result change.
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if _, found := props.Changed["Result"]; !found {
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continue
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}
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result, err := dbusx.VariantToValue[string](props.Changed["Result"])
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if err != nil {
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logging.FromContext(ctx).Debug("Could not parse result.", slog.Any("error", err))
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continue
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}
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if result == "oom-kill" {
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// Naming is defined in
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// https://systemd.io/DESKTOP_ENVIRONMENTS/. The strings seem
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// to be percent-encoded with % replaced by _.
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processStr, err := url.PathUnescape(strings.ReplaceAll(trigger.Path, "_", "%"))
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if err != nil {
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logging.FromContext(ctx).Debug("Could not unescape process path string.", slog.Any("error", err))
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}
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// Trim the D-Bus unit path prefix.
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processStr = strings.TrimPrefix(processStr, unitPathPrefix+"/")
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// Trim any "app-" prefix.
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processStr = strings.TrimPrefix(processStr, "app-")
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// Trim the ".service" suffix.
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processStr = strings.TrimSuffix(processStr, ".service")
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// Ignore the <RANDOM> string that might be appended.
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processStr, _, _ = strings.Cut(processStr, "@")
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// Get the PID.
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//nolint:errcheck
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pid, _ := dbusx.VariantToValue[int](props.Changed["MainPID"])
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if pid == 0 {
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continue
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}
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// Send an event.
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eventCh <- event.Event{
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EventType: oomEventName,
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EventData: oomEventData{
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Process: processStr,
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PID: pid,
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},
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}
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}
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}
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}
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}()
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return eventCh, nil
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}
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func NewOOMEventsWorker(ctx context.Context) (*linux.EventWorker, error) {
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worker := linux.NewEventWorker(oomEventsWorkerID)
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bus, ok := linux.CtxGetSessionBus(ctx)
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if !ok {
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return worker, linux.ErrNoSessionBus
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}
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eventWorker := &OOMEventsWorker{}
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triggerCh, err := dbusx.NewWatch(
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dbusx.MatchPathNamespace(oomDBusPath),
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dbusx.MatchPropChanged(),
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).Start(ctx, bus)
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if err != nil {
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return nil, fmt.Errorf("unable to set-up D-Bus watch for OOM events: %w", err)
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}
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eventWorker.triggerCh = triggerCh
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worker.EventType = eventWorker
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return worker, nil
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}
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