fix: handle OTLP exporter 404s discretely (#1261)

* fix: handle plain/text responses when logging

The otel-collecor uses a 404 with a plain/text content-type when the
exporter path doesn't match the one configured by the colletor. This
commit adds a check to handle this content type.

* fix: log message for 404s

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

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

Author: 3 people

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

@@ -174,6 +174,10 @@ def send_bytes(bytes, timeout:) # rubocop:disable Metrics/CyclomaticComplexity,
               response.body # Read and discard body
               redo if backoff?(retry_count: retry_count += 1, reason: response.code)
               FAILURE
+            when Net::HTTPNotFound
+              OpenTelemetry.handle_error(message: "OTLP exporter received http.code=404 for uri: '#{@path}'")
+              @metrics_reporter.add_to_counter('otel.otlp_exporter.failure', labels: { 'reason' => response.code })
+              FAILURE
             when Net::HTTPBadRequest, Net::HTTPClientError, Net::HTTPServerError
               log_status(response.body)
               @metrics_reporter.add_to_counter('otel.otlp_exporter.failure', labels: { 'reason' => response.code })

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

@@ -404,7 +404,7 @@
 
       details = [::Google::Protobuf::Any.pack(::Google::Protobuf::StringValue.new(value: 'you are a bad request'))]
       status = ::Google::Rpc::Status.encode(::Google::Rpc::Status.new(code: 1, message: 'bad request', details: details))
-      stub_request(:post, 'http://localhost:4318/v1/traces').to_return(status: 400, body: status)
+      stub_request(:post, 'http://localhost:4318/v1/traces').to_return(status: 400, body: status, headers: { 'Content-Type' => 'application/x-protobuf' })
       span_data = OpenTelemetry::TestHelpers.create_span_data
 
       result = exporter.export([span_data])
@@ -418,6 +418,25 @@
       OpenTelemetry.logger = logger
     end
 
+    it 'logs a specific message when there is a 404' do
+      log_stream = StringIO.new
+      logger = OpenTelemetry.logger
+      OpenTelemetry.logger = ::Logger.new(log_stream)
+
+      stub_request(:post, 'http://localhost:4318/v1/traces').to_return(status: 404, body: "Not Found\n")
+      span_data = OpenTelemetry::TestHelpers.create_span_data
+
+      result = exporter.export([span_data])
+
+      _(log_stream.string).must_match(
+        %r{ERROR -- : OpenTelemetry error: OTLP exporter received http\.code=404 for uri: '/v1/traces'}
+      )
+
+      _(result).must_equal(FAILURE)
+    ensure
+      OpenTelemetry.logger = logger
+    end
+
     it 'handles Zlib gzip compression errors' do
       stub_request(:post, 'http://localhost:4318/v1/traces').to_raise(Zlib::DataError.new('data error'))
       span_data = OpenTelemetry::TestHelpers.create_span_data