Correct the comment for the priority of options and environments on o…

…tlptracegrpc (open-telemetry#5508)

part of open-telemetry#5379

---------

Co-authored-by: David Ashpole <dashpole@google.com>
Co-authored-by: Chester Cheung <cheung.zhy.csu@gmail.com>
Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

CHANGELOG.md

@@ -39,6 +39,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Prevent random number generation data-race for experimental rand exemplars in `go.opentelemetry.io/otel/sdk/metric`. (#5456)
 - Fix counting number of dropped attributes of `Record` in `go.opentelemetry.io/otel/sdk/log`. (#5464)
 - Fix panic in baggage creation when a member contains 0x80 char in key or value. (#5494)
+- Correct comments for the priority of the `WithEndpoint` and `WithEndpointURL` options and their coresponding environment variables in  in `go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc`. (#5508)
 
 ## [1.27.0/0.49.0/0.3.0] 2024-05-21
 

exporters/otlp/otlptrace/otlptracegrpc/client_unit_test.go

@@ -202,3 +202,87 @@ func TestExportContextLinksStopSignal(t *testing.T) {
 		return false
 	}, 10*time.Second, time.Microsecond)
 }
+
+func TestWithEndpointWithEnv(t *testing.T) {
+	testCases := []struct {
+		name    string
+		options []Option
+		envs    map[string]string
+		want    string
+	}{
+		{
+			name: "WithEndpointURL last",
+			options: []Option{
+				WithEndpoint("foo"),
+				WithEndpointURL("http://bar:8080/path"),
+			},
+			want: "bar:8080",
+		},
+		{
+			name: "WithEndpoint last",
+			options: []Option{
+				WithEndpointURL("http://bar:8080/path"),
+				WithEndpoint("foo"),
+			},
+			want: "foo",
+		},
+		{
+			name: "OTEL_EXPORTER_OTLP_ENDPOINT only",
+			envs: map[string]string{
+				"OTEL_EXPORTER_OTLP_ENDPOINT": "foo2",
+			},
+			want: "foo2",
+		},
+		{
+			name: "OTEL_EXPORTER_OTLP_TRACES_ENDPOINT only",
+			envs: map[string]string{
+				"OTEL_EXPORTER_OTLP_TRACES_ENDPOINT": "bar2",
+			},
+			want: "bar2",
+		},
+		{
+			name: "both OTEL_EXPORTER_OTLP_ENDPOINT and OTEL_EXPORTER_OTLP_TRACES_ENDPOINT",
+			envs: map[string]string{
+				"OTEL_EXPORTER_OTLP_ENDPOINT":        "foo2",
+				"OTEL_EXPORTER_OTLP_TRACES_ENDPOINT": "bar2",
+			},
+			want: "bar2",
+		},
+		{
+			name: "both options and envs",
+			envs: map[string]string{
+				"OTEL_EXPORTER_OTLP_ENDPOINT":        "foo2",
+				"OTEL_EXPORTER_OTLP_TRACES_ENDPOINT": "bar2",
+			},
+			options: []Option{
+				WithEndpointURL("http://bar:8080/path"),
+				WithEndpoint("foo"),
+			},
+			want: "foo",
+		},
+		{
+			name: "both options and envs",
+			envs: map[string]string{
+				"OTEL_EXPORTER_OTLP_ENDPOINT":        "foo2",
+				"OTEL_EXPORTER_OTLP_TRACES_ENDPOINT": "bar2",
+			},
+			options: []Option{
+				WithEndpoint("foo"),
+				WithEndpointURL("http://bar:8080/path"),
+			},
+			want: "bar:8080",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			for key, value := range tc.envs {
+				t.Setenv(key, value)
+			}
+
+			client := newClient(tc.options...)
+
+			assert.Equal(t, tc.want, client.endpoint)
+		})
+	}
+}

exporters/otlp/otlptrace/otlptracegrpc/options.go

@@ -59,8 +59,9 @@ func WithInsecure() Option {
 //
 // If the OTEL_EXPORTER_OTLP_ENDPOINT or OTEL_EXPORTER_OTLP_TRACES_ENDPOINT
 // environment variable is set, and this option is not passed, that variable
-// value will be used. If both are set, OTEL_EXPORTER_OTLP_TRACES_ENDPOINT
-// will take precedence.
+// value will be used. If both environment variables are set,
+// OTEL_EXPORTER_OTLP_TRACES_ENDPOINT will take precedence. If an environment
+// variable is set, and this option is passed, this option will take precedence.
 //
 // If both this option and WithEndpointURL are used, the last used option will
 // take precedence.
@@ -79,8 +80,9 @@ func WithEndpoint(endpoint string) Option {
 //
 // If the OTEL_EXPORTER_OTLP_ENDPOINT or OTEL_EXPORTER_OTLP_TRACES_ENDPOINT
 // environment variable is set, and this option is not passed, that variable
-// value will be used. If both are set, OTEL_EXPORTER_OTLP_TRACES_ENDPOINT
-// will take precedence.
+// value will be used. If both environment variables are set,
+// OTEL_EXPORTER_OTLP_TRACES_ENDPOINT will take precedence. If an environment
+// variable is set, and this option is passed, this option will take precedence.
 //
 // If both this option and WithEndpoint are used, the last used option will
 // take precedence.