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Merged
damemi merged 7 commits into from
Mar 16, 2026
Merged

Dynamic add/remove of PID selection #1388

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09bbd7d
Dynamic add/remove of PID selection
damemi Feb 27, 2026
8c53236
Notify attacher of delete events
damemi Mar 6, 2026
ff1cf8a
Refactor to DynamicPidSelector
damemi Mar 11, 2026
6c84c6e
Notify watcher to forget already seen pids on dynamic add
damemi Mar 13, 2026
23dcb8c
Add/remove buffer queues and make dynamic criteria once
damemi Mar 13, 2026
218366b
Remove redundant runWithNotify/swarms call
damemi Mar 13, 2026
c401fcd
Refactor forgetPidsNotify
damemi Mar 13, 2026
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2 changes: 1 addition & 1 deletion docs/config-schema.json
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Original file line number Diff line number Diff line change
Expand Up @@ -671,7 +671,7 @@
"type": "integer"
},
"type": "array",
"description": "PIDs allows selecting processes by PID. When non-empty, the process PID must be in this list (in addition to any path/port criteria).",
"description": "PIDs allows selecting processes by PID (static from config). When non-empty, the process PID must be in this list.",
"x-env-var": "OTEL_EBPF_TARGET_PID"
}
},
Expand Down
5 changes: 4 additions & 1 deletion pkg/appolly/discover/attacher.go
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,9 @@ import (
"go.opentelemetry.io/obi/pkg/pipe/swarm/swarms"
)

// Swappable in tests so attacher tests don't depend on memlock permissions.
var removeMemlock = rlimit.RemoveMemlock

// traceAttacher creates the available trace.Tracer implementations (Go HTTP tracer, GRPC tracer, Generic tracer...)
// for each received Instrumentable process and forwards an ebpf.ProcessTracer instance ready to run and start
// instrumenting the executable
Expand Down Expand Up @@ -411,7 +414,7 @@ func (ta *traceAttacher) notifyProcessDeletion(ie *ebpf.Instrumentable) {
}

func (ta *traceAttacher) init() error {
if err := rlimit.RemoveMemlock(); err != nil {
if err := removeMemlock(); err != nil {
return fmt.Errorf("removing memory lock: %w", err)
}
return nil
Expand Down
201 changes: 201 additions & 0 deletions pkg/appolly/discover/attacher_test.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,201 @@
// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0

package discover

import (
"context"
"io"
"testing"

cebpf "github.com/cilium/ebpf"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"

"go.opentelemetry.io/obi/pkg/appolly/app"
"go.opentelemetry.io/obi/pkg/appolly/app/request"
"go.opentelemetry.io/obi/pkg/appolly/app/svc"
execpkg "go.opentelemetry.io/obi/pkg/appolly/discover/exec"
"go.opentelemetry.io/obi/pkg/appolly/services"
"go.opentelemetry.io/obi/pkg/ebpf"
ebpfcommon "go.opentelemetry.io/obi/pkg/ebpf/common"
"go.opentelemetry.io/obi/pkg/export/imetrics"
"go.opentelemetry.io/obi/pkg/internal/goexec"
"go.opentelemetry.io/obi/pkg/internal/testutil"
"go.opentelemetry.io/obi/pkg/obi"
"go.opentelemetry.io/obi/pkg/pipe/msg"
)

type blockedPID struct {
pid app.PID
ns uint32
}

type recordingTracer struct {
blocked []blockedPID
}

func (r *recordingTracer) AllowPID(app.PID, uint32, *svc.Attrs) {}
func (r *recordingTracer) BlockPID(pid app.PID, ns uint32) {
r.blocked = append(r.blocked, blockedPID{pid: pid, ns: ns})
}
func (r *recordingTracer) LoadSpecs() ([]*ebpfcommon.SpecBundle, error) { return nil, nil }
func (r *recordingTracer) AddCloser(...io.Closer) {}
func (r *recordingTracer) SetupTailCalls() {}
func (r *recordingTracer) KProbes() map[string]ebpfcommon.ProbeDesc { return nil }
func (r *recordingTracer) Tracepoints() map[string]ebpfcommon.ProbeDesc { return nil }
func (r *recordingTracer) GoProbes() map[string][]*ebpfcommon.ProbeDesc { return nil }
func (r *recordingTracer) UProbes() map[string]map[string][]*ebpfcommon.ProbeDesc { return nil }
func (r *recordingTracer) SocketFilters() []*cebpf.Program { return nil }
func (r *recordingTracer) SockMsgs() []ebpfcommon.SockMsg { return nil }
func (r *recordingTracer) SockOps() []ebpfcommon.SockOps { return nil }
func (r *recordingTracer) Iters() []*ebpfcommon.Iter { return nil }
func (r *recordingTracer) Tracing() []*ebpfcommon.Tracing { return nil }
func (r *recordingTracer) RecordInstrumentedLib(uint64, []io.Closer) {}
func (r *recordingTracer) AddInstrumentedLibRef(uint64) {}
func (r *recordingTracer) AlreadyInstrumentedLib(uint64) bool { return false }
func (r *recordingTracer) UnlinkInstrumentedLib(uint64) {}
func (r *recordingTracer) RegisterOffsets(*execpkg.FileInfo, *goexec.Offsets) {}
func (r *recordingTracer) ProcessBinary(*execpkg.FileInfo) {}
func (r *recordingTracer) Required() bool { return false }
func (r *recordingTracer) Run(context.Context, *ebpfcommon.EBPFEventContext, *msg.Queue[[]request.Span]) {
}

func TestSyntheticDeletePath_TraceAttacherDeletesTracer(t *testing.T) {
ctx, cancel := context.WithCancel(t.Context())
defer cancel()
origRemoveMemlock := removeMemlock
removeMemlock = func() error { return nil }
defer func() { removeMemlock = origRemoveMemlock }()

processMatches := msg.NewQueue[[]Event[ProcessMatch]](msg.ChannelBufferLen(10))
instrumentables := msg.NewQueue[[]Event[ebpf.Instrumentable]](msg.ChannelBufferLen(10))
tracerEventsQu := msg.NewQueue[Event[*ebpf.Instrumentable]](msg.ChannelBufferLen(10))
tracerEvents := tracerEventsQu.Subscribe()

fileInfo := &execpkg.FileInfo{
Service: svc.Attrs{UID: svc.UID{Name: "dyn-svc", Namespace: "ns"}},
CmdExePath: "/bin/test",
Pid: 42,
Ino: 1234,
Ns: 17,
}
startDeletedTyperPipeline(ctx, &typer{
currentPids: map[app.PID]*execpkg.FileInfo{42: fileInfo},
}, processMatches, instrumentables)

ta := &traceAttacher{
Cfg: &obi.Config{},
Metrics: imetrics.NoopReporter{},
InputInstrumentables: instrumentables,
OutputTracerEvents: tracerEventsQu,
EbpfEventContext: &ebpfcommon.EBPFEventContext{},
}
run, err := ta.attacherLoop(ctx)
require.NoError(t, err)

prog := &recordingTracer{}
tracer := &ebpf.ProcessTracer{Type: ebpf.Generic, Programs: []ebpf.Tracer{prog}}
ta.existingTracers[fileInfo.Ino] = tracer
ta.processInstances.Inc(fileInfo.Ino)

go run(ctx)

processMatches.Send([]Event[ProcessMatch]{{
Type: EventDeleted,
Obj: ProcessMatch{
Process: &services.ProcessInfo{Pid: 42},
},
}})

ev := testutil.ReadChannel(t, tracerEvents, testTimeout)
require.Equal(t, EventDeleted, ev.Type)
require.NotNil(t, ev.Obj)
assert.Equal(t, app.PID(42), ev.Obj.FileInfo.Pid)
assert.Same(t, tracer, ev.Obj.Tracer)
assert.Equal(t, []blockedPID{{pid: 42, ns: 17}}, prog.blocked)
_, exists := ta.existingTracers[fileInfo.Ino]
assert.False(t, exists)
}

func TestSyntheticDeletePath_TraceAttacherDeletesInstance(t *testing.T) {
ctx, cancel := context.WithCancel(t.Context())
defer cancel()
origRemoveMemlock := removeMemlock
removeMemlock = func() error { return nil }
defer func() { removeMemlock = origRemoveMemlock }()

processMatches := msg.NewQueue[[]Event[ProcessMatch]](msg.ChannelBufferLen(10))
instrumentables := msg.NewQueue[[]Event[ebpf.Instrumentable]](msg.ChannelBufferLen(10))
tracerEventsQu := msg.NewQueue[Event[*ebpf.Instrumentable]](msg.ChannelBufferLen(10))
tracerEvents := tracerEventsQu.Subscribe()

fileInfo := &execpkg.FileInfo{
Service: svc.Attrs{UID: svc.UID{Name: "dyn-svc", Namespace: "ns"}},
CmdExePath: "/bin/test",
Pid: 42,
Ino: 1234,
Ns: 17,
}
startDeletedTyperPipeline(ctx, &typer{
currentPids: map[app.PID]*execpkg.FileInfo{42: fileInfo},
}, processMatches, instrumentables)

ta := &traceAttacher{
Cfg: &obi.Config{},
Metrics: imetrics.NoopReporter{},
InputInstrumentables: instrumentables,
OutputTracerEvents: tracerEventsQu,
EbpfEventContext: &ebpfcommon.EBPFEventContext{},
}
run, err := ta.attacherLoop(ctx)
require.NoError(t, err)

prog := &recordingTracer{}
tracer := &ebpf.ProcessTracer{Type: ebpf.Generic, Programs: []ebpf.Tracer{prog}}
ta.existingTracers[fileInfo.Ino] = tracer
ta.processInstances.Inc(fileInfo.Ino)
ta.processInstances.Inc(fileInfo.Ino)

go run(ctx)

processMatches.Send([]Event[ProcessMatch]{{
Type: EventDeleted,
Obj: ProcessMatch{
Process: &services.ProcessInfo{Pid: 42},
},
}})

ev := testutil.ReadChannel(t, tracerEvents, testTimeout)
require.Equal(t, EventInstanceDeleted, ev.Type)
require.NotNil(t, ev.Obj)
assert.Equal(t, app.PID(42), ev.Obj.FileInfo.Pid)
assert.Nil(t, ev.Obj.Tracer)
assert.Equal(t, []blockedPID{{pid: 42, ns: 17}}, prog.blocked)
assert.Same(t, tracer, ta.existingTracers[fileInfo.Ino])
}

func startDeletedTyperPipeline(
ctx context.Context,
tp *typer,
input *msg.Queue[[]Event[ProcessMatch]],
output *msg.Queue[[]Event[ebpf.Instrumentable]],
) {
in := input.Subscribe(msg.SubscriberName("testExecTyper"))
go func() {
defer output.Close()
for {
select {
case <-ctx.Done():
return
case evs, ok := <-in:
if !ok {
return
}
if out := tp.FilterClassify(evs); len(out) > 0 {
output.Send(out)
}
}
}
}()
}
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