[extension/opamp]: Add mechanism to detect whether the collector has …

…been orphaned (open-telemetry#32564)

**Description:** <Describe what has changed.>
* Allows the process to monitor a passed in ppid, which should be the
parent process ID for the collector. When the parent process ID exits,
the extension emits a fatal error event, which triggers a collector
shutdown.

**Link to tracking Issue:** This is part of open-telemetry#32189 - It does not resolve
this issue because the supervisor still needs changes to pass the its
PID in.

**Testing:**
Added some unit tests.

I've manually tested it on my macbook with this PR:
observIQ#4715
(running supervisor, kill -9 the supervisor, and take a look at the
agent logs to see it shut down).

I've tried testing this out on Windows, but the supervisor doesn't get
past bootstrapping (the Commander's Stop function does not work on
windows), so I wasn't able to fully test it.

**Documentation:** 
Added new parameter to README

.chloggen/feat_opamp-extension-monitor-ppid.yaml

@@ -0,0 +1,13 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: opampextension
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add a new `ppid` parameter that can be used to enable orphan detection for the supervisor.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [32189]

cmd/otelcontribcol/go.mod

@@ -648,8 +648,8 @@ require (
  github.com/tidwall/wal v1.1.7 // indirect
  github.com/tilinna/clock v1.1.0 // indirect
  github.com/tinylib/msgp v1.1.9 // indirect
- github.com/tklauser/go-sysconf v0.3.12 // indirect
- github.com/tklauser/numcpus v0.6.1 // indirect
+ github.com/tklauser/go-sysconf v0.3.14 // indirect
+ github.com/tklauser/numcpus v0.8.0 // indirect
  github.com/valyala/fastjson v1.6.4 // indirect
  github.com/vincent-petithory/dataurl v1.0.0 // indirect
  github.com/vishvananda/netlink v1.1.1-0.20201029203352-d40f9887b852 // indirect

extension/opampextension/README.md

@@ -32,6 +32,8 @@ The following settings are optional:
  - `reports_effective_config`: Whether to enable the OpAMP ReportsEffectiveConfig capability. Default is `true`.
 - `agent_description`: Setting that modifies the agent description reported to the OpAMP server.
  - `non_identifying_attributes`: A map of key value pairs that will be added to the [non-identifying attributes](https://github.com/open-telemetry/opamp-spec/blob/main/specification.md#agentdescriptionnon_identifying_attributes) reported to the OpAMP server. If an attribute collides with the default non-identifying attributes that are automatically added, the ones specified here take precedence.
+- `ppid`: An optional process ID to monitor. When this process is no longer running, the extension will emit a fatal error, causing the collector to exit. This is meant to be set by the Supervisor or some other parent process, and should not be configured manually.
+- `ppid_poll_interval`: The poll interval between check for whether `ppid` is still alive or not. Defaults to 5 seconds.
 
 ### Example
 

extension/opampextension/config.go

@@ -6,6 +6,7 @@ package opampextension // import "github.com/open-telemetry/opentelemetry-collec
 import (
  "errors"
  "net/url"
+ "time"
 
  "github.com/oklog/ulid/v2"
  "github.com/open-telemetry/opamp-go/client"
@@ -29,6 +30,15 @@ type Config struct {
 
  // Agent descriptions contains options to modify the AgentDescription message
  AgentDescription AgentDescription `mapstructure:"agent_description"`
+
+ // PPID is the process ID of the parent for the collector. If the PPID is specified,
+ // the extension will continuously poll for the status of the parent process, and emit a fatal error
+ // when the parent process is no longer running.
+ // If unspecified, the orphan detection logic does not run.
+ PPID int32 `mapstructure:"ppid"`
+
+ // PPIDPollInterval is the time between polling for whether PPID is running.
+ PPIDPollInterval time.Duration `mapstructure:"ppid_poll_interval"`
 }
 
 type AgentDescription struct {

extension/opampextension/config_test.go

@@ -6,6 +6,7 @@ package opampextension
 import (
  "path/filepath"
  "testing"
+ "time"
 
  "github.com/stretchr/testify/assert"
  "github.com/stretchr/testify/require"
@@ -40,6 +41,7 @@ func TestUnmarshalConfig(t *testing.T) {
  Capabilities: Capabilities{
  ReportsEffectiveConfig: true,
  },
+ PPIDPollInterval: 5 * time.Second,
  }, cfg)
 }
 
@@ -60,6 +62,7 @@ func TestUnmarshalHttpConfig(t *testing.T) {
  Capabilities: Capabilities{
  ReportsEffectiveConfig: true,
  },
+ PPIDPollInterval: 5 * time.Second,
  }, cfg)
 }
 

extension/opampextension/factory.go

@@ -5,6 +5,7 @@ package opampextension // import "github.com/open-telemetry/opentelemetry-collec
 
 import (
  "context"
+ "time"
 
  "go.opentelemetry.io/collector/component"
  "go.opentelemetry.io/collector/extension"
@@ -27,9 +28,10 @@ func createDefaultConfig() component.Config {
  Capabilities: Capabilities{
  ReportsEffectiveConfig: true,
  },
+ PPIDPollInterval: 5 * time.Second,
  }
 }
 
 func createExtension(_ context.Context, set extension.CreateSettings, cfg component.Config) (extension.Extension, error) {
- return newOpampAgent(cfg.(*Config), set.Logger, set.BuildInfo, set.Resource)
+ return newOpampAgent(cfg.(*Config), set)
 }

extension/opampextension/go.mod

@@ -6,13 +6,13 @@ require (
  github.com/google/uuid v1.6.0
  github.com/oklog/ulid/v2 v2.1.0
  github.com/open-telemetry/opamp-go v0.14.0
+ github.com/shirou/gopsutil/v3 v3.24.3
  github.com/stretchr/testify v1.9.0
  go.opentelemetry.io/collector/component v0.99.1-0.20240503164040-109173d9cf84
  go.opentelemetry.io/collector/config/configopaque v1.6.1-0.20240503164040-109173d9cf84
  go.opentelemetry.io/collector/config/configtls v0.99.1-0.20240503164040-109173d9cf84
  go.opentelemetry.io/collector/confmap v0.99.1-0.20240503164040-109173d9cf84
  go.opentelemetry.io/collector/extension v0.99.1-0.20240503164040-109173d9cf84
- go.opentelemetry.io/collector/pdata v1.6.1-0.20240503164040-109173d9cf84
  go.opentelemetry.io/collector/semconv v0.99.1-0.20240503164040-109173d9cf84
  go.opentelemetry.io/otel/metric v1.26.0
  go.opentelemetry.io/otel/trace v1.26.0
@@ -30,21 +30,29 @@ require (
  github.com/fsnotify/fsnotify v1.7.0 // indirect
  github.com/go-logr/logr v1.4.1 // indirect
  github.com/go-logr/stdr v1.2.2 // indirect
+ github.com/go-ole/go-ole v1.2.6 // indirect
  github.com/go-viper/mapstructure/v2 v2.0.0-alpha.1 // indirect
  github.com/gogo/protobuf v1.3.2 // indirect
  github.com/gorilla/websocket v1.5.1 // indirect
  github.com/knadh/koanf/maps v0.1.1 // indirect
  github.com/knadh/koanf/providers/confmap v0.1.0 // indirect
  github.com/knadh/koanf/v2 v2.1.1 // indirect
+ github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0 // indirect
  github.com/mitchellh/copystructure v1.2.0 // indirect
  github.com/mitchellh/reflectwalk v1.0.2 // indirect
  github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+ github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c // indirect
  github.com/prometheus/client_golang v1.19.0 // indirect
  github.com/prometheus/client_model v0.6.1 // indirect
  github.com/prometheus/common v0.53.0 // indirect
  github.com/prometheus/procfs v0.12.0 // indirect
  github.com/rogpeppe/go-internal v1.11.0 // indirect
+ github.com/shoenig/go-m1cpu v0.1.6 // indirect
+ github.com/tklauser/go-sysconf v0.3.14 // indirect
+ github.com/tklauser/numcpus v0.8.0 // indirect
+ github.com/yusufpapurcu/wmi v1.2.4 // indirect
  go.opentelemetry.io/collector/config/configtelemetry v0.99.1-0.20240503164040-109173d9cf84 // indirect
+ go.opentelemetry.io/collector/pdata v1.6.1-0.20240503164040-109173d9cf84 // indirect
  go.opentelemetry.io/otel v1.26.0 // indirect
  go.opentelemetry.io/otel/exporters/prometheus v0.48.0 // indirect
  go.opentelemetry.io/otel/sdk v1.26.0 // indirect

extension/opampextension/monitor_ppid.go

@@ -0,0 +1,40 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package opampextension // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/opampextension"
+
+import (
+ "context"
+ "fmt"
+ "time"
+
+ "github.com/shirou/gopsutil/v3/process"
+ "go.opentelemetry.io/collector/component"
+)
+
+// monitorPPID polls for the existence of ppid.
+// If the specified ppid no longer exists, a fatal error event is reported via the passed in reportStatus function.
+func monitorPPID(ctx context.Context, interval time.Duration, ppid int32, reportStatus func(*component.StatusEvent)) {
+ for {
+ exists, err := process.PidExistsWithContext(ctx, ppid)
+ if err != nil {
+ statusErr := fmt.Errorf("collector was orphaned, failed to find process with pid %d: %w", ppid, err)
+ status := component.NewFatalErrorEvent(statusErr)
+ reportStatus(status)
+ return
+ }
+
+ if !exists {
+ statusErr := fmt.Errorf("collector was orphaned, process with pid %d does not exist", ppid)
+ status := component.NewFatalErrorEvent(statusErr)
+ reportStatus(status)
+ return
+ }
+
+ select {
+ case <-time.After(interval): // OK; Poll again to make sure PID exists
+ case <-ctx.Done():
+ return
+ }
+ }
+}