HeaderInjector doesn't work

[hyhong]

I use HeaderInjector for a rpc call,but it doesn't form a trace.The client code is:

    Transaction  transaction = ElasticApm.currentTransaction();
    Span span = transaction.startSpan("external", "tcp", null).setName(methodName);
    		span.activate();
    		try{
    			span.injectTraceHeaders(new HeaderInjector() {
    				@Override
    				public void addHeader(String headerName, String headerValue) {
    					context.put(headerName, headerValue);
    				}
    			});
    		} catch (Exception e) {
    			span.captureException(e);
                span.end();
    		}

The server code:

    Transaction  transaction = ElasticApm.startTransactionWithRemoteParent(new HeaderExtractor() {
    			@Override
    			public String getFirstHeader(String headerName) {
    				return context.get(headerName);
    			}
    		});
    	    transaction.activate();
    	    try {
    	    	transaction.setName("tcp-server");
    		    transaction.setType(Transaction.TYPE_REQUEST);
    	    } catch (Exception e) {
    	        transaction.captureException(e);
                transaction.end();
    	    }

[felixbarny (Felix Barnsteiner)]

Could you add log statements to addHeader and getFirstHeader to see the values it adds and gets?

Also, you should use try-with-resources blocks when using activate(). See the example here: https://www.elastic.co/guide/en/apm/agent/java/current/public-api.html#api-transaction-inject-trace-headers

[hyhong]

If I creat a new transtraction it’s work,but if achieve current transtraction it’s doesn’t work

[felixbarny (Felix Barnsteiner)]

That probably means that there is no current transaction.