From d80074c5d22f43869e7d1cfac48d6070c7dde896 Mon Sep 17 00:00:00 2001
From: Ashley Jeffs <ash@jeffail.uk>
Date: Wed, 14 Feb 2024 17:00:24 +0000
Subject: [PATCH] Tidy up some fields

---
 CHANGELOG.md                                  |  1 +
 internal/impl/otlp/tracer_otlp.go             | 19 ++++++++++---------
 .../tracers/open_telemetry_collector.md       | 13 +++++++++++--
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5187ab2c91..629338ad65 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ All notable changes to this project will be documented in this file.
 - Field `read_header` added to the `amqp_1` input.
 - A debug endpoint `/debug/pprof/allocs` has been added for profiling allocations.
 - New `cockroachdb_changefeed` input.
+- The `open_telemetry_collector` tracer now supports sampling.
 
 ### Fixed
 
diff --git a/internal/impl/otlp/tracer_otlp.go b/internal/impl/otlp/tracer_otlp.go
index 9e87fcddcf..460e211dc8 100644
--- a/internal/impl/otlp/tracer_otlp.go
+++ b/internal/impl/otlp/tracer_otlp.go
@@ -39,19 +39,18 @@ func init() {
 		).Description("A list of grpc collectors.")).
 		Field(service.NewStringMapField("tags").
 			Description("A map of tags to add to all tracing spans.").
-			Default(map[string]string{}).
+			Default(map[string]any{}).
 			Advanced()).
 		Field(service.NewObjectField("sampling",
 			service.NewBoolField("enabled").
 				Description("Whether to enable sampling.").
-				Default(false).
-				Optional(),
+				Default(false),
 			service.NewFloatField("ratio").
 				Description("Sets the ratio of traces to sample.").
-				Default(1.0).
-				Advanced().
+				Examples(0.85, 0.5).
 				Optional()).
-			Description("Settings for trace sampling. Sampling is recommended for high-volume production workloads."))
+			Description("Settings for trace sampling. Sampling is recommended for high-volume production workloads.").
+			Version("4.25.0"))
 
 	err := service.RegisterOtelTracerProvider(
 		"open_telemetry_collector",
@@ -146,9 +145,11 @@ func sampleConfigFromParsed(conf *service.ParsedConfig) (sampleConfig, error) {
 		return sampleConfig{}, err
 	}
 
-	ratio, err := conf.FieldFloat("ratio")
-	if err != nil {
-		return sampleConfig{}, err
+	var ratio float64
+	if conf.Contains("ratio") {
+		if ratio, err = conf.FieldFloat("ratio"); err != nil {
+			return sampleConfig{}, err
+		}
 	}
 
 	return sampleConfig{
diff --git a/website/docs/components/tracers/open_telemetry_collector.md b/website/docs/components/tracers/open_telemetry_collector.md
index 7f5ac8a278..9cb6b42aa5 100644
--- a/website/docs/components/tracers/open_telemetry_collector.md
+++ b/website/docs/components/tracers/open_telemetry_collector.md
@@ -34,6 +34,7 @@ tracer:
     grpc: [] # No default (required)
     sampling:
       enabled: false
+      ratio: 0.85 # No default (optional)
 ```
 
 </TabItem>
@@ -48,7 +49,7 @@ tracer:
     tags: {}
     sampling:
       enabled: false
-      ratio: 1
+      ratio: 0.85 # No default (optional)
 ```
 
 </TabItem>
@@ -116,6 +117,7 @@ Settings for trace sampling. Sampling is recommended for high-volume production
 
 
 Type: `object`  
+Requires version 4.25.0 or newer  
 
 ### `sampling.enabled`
 
@@ -131,6 +133,13 @@ Sets the ratio of traces to sample.
 
 
 Type: `float`  
-Default: `1`  
+
+```yml
+# Examples
+
+ratio: 0.85
+
+ratio: 0.5
+```