SimpleLogRecordProcessor, SimpleSpanProcessor call export concurrently, but shouldn't

[jack-berg]

SpanExporter#export, LogRecordExporter#export should not be called concurrently, but SimpleSpanProcessor, SimpleLogRecordExporter don't have any synchronization:

opentelemetry-java/sdk/trace/src/main/java/io/opentelemetry/sdk/trace/export/SimpleSpanProcessor.java

Lines 84 to 102 in ee7fd27

	@Override
	public void onEnd(ReadableSpan span) {
	if (span != null && (exportUnsampledSpans || span.getSpanContext().isSampled())) {
	try {
	List<SpanData> spans = Collections.singletonList(span.toSpanData());
	CompletableResultCode result = spanExporter.export(spans);
	pendingExports.add(result);
	result.whenComplete(
	() -> {
	pendingExports.remove(result);
	if (!result.isSuccess()) {
	logger.log(Level.FINE, "Exporter failed");
	}
	});
	} catch (RuntimeException e) {
	logger.log(Level.WARNING, "Exporter threw an Exception", e);
	}
	}
	}

opentelemetry-java/sdk/logs/src/main/java/io/opentelemetry/sdk/logs/export/SimpleLogRecordProcessor.java

Lines 63 to 79 in ee7fd27

	@Override
	public void onEmit(Context context, ReadWriteLogRecord logRecord) {
	try {
	List<LogRecordData> logs = Collections.singletonList(logRecord.toLogRecordData());
	CompletableResultCode result = logRecordExporter.export(logs);
	pendingExports.add(result);
	result.whenComplete(
	() -> {
	pendingExports.remove(result);
	if (!result.isSuccess()) {
	logger.log(Level.FINE, "Exporter failed");
	}
	});
	} catch (RuntimeException e) {
	logger.log(Level.WARNING, "Exporter threw an Exception", e);
	}
	}

Noted by @pellared in open-telemetry/opentelemetry-specification#4134 (comment)

[pellared]

Credits go to @cijothomas (not me 😉)

[slodha]

i'm working on this issue.