[receiver/prometheusexec] mark receiver as deprecated

After many discussions it seems the community is leaning towards removing the components that execute subprocesses. As such, marking the prom_exec receiver as deprecated.

Fixes open-telemetry#6722

CHANGELOG.md

@@ -18,6 +18,7 @@
 - `datadogexporter`: Deprecate `service` setting in favor of `service.name` semantic convention (#8784)
 - `datadogexporter`: Deprecate `version` setting in favor of `service.version` semantic convention (#8784)
 - `datadogexporter`: Deprecate `GetHostTags` method from `TagsConfig` struct (#8975)
+- `prometheusexecreceiver`: Deprecate prom_exec receiver ()
 
 ### 🚀 New components 🚀
 

receiver/prometheusexecreceiver/README.md

@@ -1,4 +1,7 @@
-# prometheus_exec Receiver
+# Deprecated prometheus_exec Receiver
+
+This receiver has been deprecated due to security concerns around the ability to specify the execution of
+any arbitrary processes via its configuration. See [#6722](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/6722) for additional details.
 
 This receiver makes it easy for a user to collect metrics from third-party
 services **via Prometheus exporters**. It's meant for people who want a

receiver/prometheusexecreceiver/factory.go

@@ -16,11 +16,13 @@ package prometheusexecreceiver // import "github.com/open-telemetry/opentelemetr
 
 import (
 	"context"
+	"sync"
 	"time"
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/config"
 	"go.opentelemetry.io/collector/consumer"
+	"go.uber.org/zap"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/prometheusexecreceiver/subprocessmanager"
 )
@@ -34,6 +36,8 @@ const (
 	defaultTimeoutInterval    = 10 * time.Second
 )
 
+var once sync.Once
+
 // NewFactory creates a factory for the prometheusexec receiver
 func NewFactory() component.ReceiverFactory {
 	return component.NewReceiverFactory(
@@ -42,6 +46,12 @@ func NewFactory() component.ReceiverFactory {
 		component.WithMetricsReceiver(createMetricsReceiver))
 }
 
+func logDeprecation(logger *zap.Logger) {
+	once.Do(func() {
+		logger.Warn("prometheus_exec receiver is deprecated and will be removed in future versions.")
+	})
+}
+
 // createDefaultConfig returns a default config
 func createDefaultConfig() config.Receiver {
 	return &Config{
@@ -61,6 +71,7 @@ func createMetricsReceiver(
 	cfg config.Receiver,
 	nextConsumer consumer.Metrics,
 ) (component.MetricsReceiver, error) {
+	logDeprecation(params.Logger)
 	rCfg := cfg.(*Config)
 	return newPromExecReceiver(params, rCfg, nextConsumer)
 }