fix: OTEL_EXPORTER_OTLP_ENDPOINT appends the correct path with a trailing slash (#1339)

* fix: OTEL_EXPORTER_OTLP_ENDPOINT appends the correct path with a trailing slash

* use File.join

* use URI.join

Co-authored-by: Francis Bogsanyi <[email protected]>

* remove constant

Co-authored-by: Francis Bogsanyi <[email protected]>

* remove extra empty line

Co-authored-by: Francis Bogsanyi <[email protected]>

Author: pkanal

exporter/otlp/lib/opentelemetry/exporter/otlp/exporter.rb

@@ -56,7 +56,7 @@ def initialize(endpoint: OpenTelemetry::Common::Utilities.config_opt('OTEL_EXPOR
           raise ArgumentError, "unsupported compression key #{compression}" unless compression.nil? || %w[gzip none].include?(compression)
 
           @uri = if endpoint == ENV['OTEL_EXPORTER_OTLP_ENDPOINT']
-                   URI("#{endpoint}/v1/traces")
+                   URI.join(endpoint, 'v1/traces')
                  else
                    URI(endpoint)
                  end

exporter/otlp/test/opentelemetry/exporter/otlp/exporter_test.rb

@@ -110,6 +110,24 @@
       _(http.port).must_equal 4321
     end
 
+    it 'appends the correct path if OTEL_EXPORTER_OTLP_ENDPOINT has a trailing slash' do
+      exp = OpenTelemetry::TestHelpers.with_env(
+        'OTEL_EXPORTER_OTLP_ENDPOINT' => 'https://localhost:1234/'
+      ) do
+        OpenTelemetry::Exporter::OTLP::Exporter.new()
+      end
+      _(exp.instance_variable_get(:@path)).must_equal '/v1/traces'
+    end
+
+    it 'appends the correct path if OTEL_EXPORTER_OTLP_ENDPOINT does not have a trailing slash' do
+      exp = OpenTelemetry::TestHelpers.with_env(
+        'OTEL_EXPORTER_OTLP_ENDPOINT' => 'https://localhost:1234'
+      ) do
+        OpenTelemetry::Exporter::OTLP::Exporter.new()
+      end
+      _(exp.instance_variable_get(:@path)).must_equal '/v1/traces'
+    end
+
     it 'restricts explicit headers to a String or Hash' do
       exp = OpenTelemetry::Exporter::OTLP::Exporter.new(headers: { 'token' => 'über' })
       _(exp.instance_variable_get(:@headers)).must_equal('token' => 'über')