Error: Can't set headers after they are sent.

[janvda]

Hi

I have tried to follow the instructions specified in the tutorial https://developer.ibm.com/node/2017/07/26/visualize-node-red-flow-performance-using-node-application-metrics/ but I get below error log:

I have added the following 2 instructions after the first line in my red.js which are causing the error:

var dash = require('appmetrics-dash');
dash.attach();

The following release specifies the setup of the container node-red-test that has this problem : https://github.com/janvda/balena-node-red-mqtt-nginx-TIG-stack/tree/appmetrics-dash-error

27.11.18 23:17:53 (+0100)  node-red-test  /usr/bin/entry.sh: line 29: /etc/hostname: Permission denied
27.11.18 23:17:53 (+0100)  node-red-test  /usr/bin/entry.sh: line 30: /etc/hosts: Permission denied
27.11.18 23:17:53 (+0100)  node-red-test  hostname: you must be root to change the host name
27.11.18 23:17:53 (+0100)  node-red-test  mount: only root can use "--types" option
27.11.18 23:17:53 (+0100)  node-red-test  mount: only root can use "--move" option
27.11.18 23:17:53 (+0100)  node-red-test  mount: only root can use "--move" option
27.11.18 23:17:53 (+0100)  node-red-test  mount: only root can use "--move" option
27.11.18 23:17:53 (+0100)  node-red-test  mount: only root can use "--move" option
27.11.18 23:17:53 (+0100)  node-red-test  umount: /dev: umount failed: Operation not permitted
27.11.18 23:17:53 (+0100)  node-red-test  mount: only root can use "--move" option
27.11.18 23:17:53 (+0100)  node-red-test  ln: cannot remove ‘/dev/ptmx’: Permission denied
27.11.18 23:17:53 (+0100)  node-red-test  mount: only root can use "--types" option
27.11.18 23:17:53 (+0100)  node-red-test  /sbin/udevd
27.11.18 23:17:55 (+0100)  node-red-test  npm info it worked if it ends with ok
27.11.18 23:17:55 (+0100)  node-red-test  npm info using npm@5.0.3
27.11.18 23:17:55 (+0100)  node-red-test  npm info using node@v8.1.3
npm info lifecycle node-red-docker@1.0.0~prestart: node-red-docker@1.0.0
npm info lifecycle node-red-docker@1.0.0~start: node-red-docker@1.0.0
27.11.18 23:17:56 (+0100)  node-red-test
27.11.18 23:17:56 (+0100)  node-red-test  > node-red-docker@1.0.0 start /usr/src/node-red
27.11.18 23:17:56 (+0100)  node-red-test  > node $NODE_OPTIONS node_modules/node-red/red.js -v $FLOWS "--userDir" "/data"
27.11.18 23:17:56 (+0100)  node-red-test
27.11.18 23:17:56 (+0100)  node-red-test  [Tue Nov 27 22:17:56 2018] com.ibm.diagnostics.healthcenter.loader INFO: Node Application Metrics 4.0.1.201811271705 (Agent Core 3.2.9)
27.11.18 23:18:00 (+0100)  node-red-test  [Tue Nov 27 22:18:00 2018] com.ibm.diagnostics.healthcenter.mqtt INFO: Connecting to broker localhost:1883
27.11.18 23:18:01 (+0100)  node-red-test  27 Nov 22:18:01 - [info]
27.11.18 23:18:01 (+0100)  node-red-test
27.11.18 23:18:01 (+0100)  node-red-test  Welcome to Node-RED
27.11.18 23:18:01 (+0100)  node-red-test  ===================
27.11.18 23:18:01 (+0100)  node-red-test
27.11.18 23:18:01 (+0100)  node-red-test  27 Nov 22:18:01 - [info] Node-RED version: v0.19.5
27.11.18 23:18:01 (+0100)  node-red-test  27 Nov 22:18:01 - [info] Node.js  version: v8.1.3
27.11.18 23:18:01 (+0100)  node-red-test  27 Nov 22:18:01 - [info] Linux 4.14.39 arm LE
27.11.18 23:18:03 (+0100)  node-red-test  27 Nov 22:18:03 - [info] Loading palette nodes
27.11.18 23:18:07 (+0100)  node-red-test  27 Nov 22:18:07 - [info] Dashboard version 2.11.0 started at /node-red-test/ui
27.11.18 23:18:07 (+0100)  node-red-test  27 Nov 22:18:07 - [info] Settings file  : /data/settings.js
27.11.18 23:18:07 (+0100)  node-red-test  27 Nov 22:18:07 - [info] Context store  : 'default' [module=memory]
27.11.18 23:18:07 (+0100)  node-red-test  27 Nov 22:18:07 - [info] User directory : /data
27.11.18 23:18:07 (+0100)  node-red-test  27 Nov 22:18:07 - [warn] No active project : using default flows file
27.11.18 23:18:07 (+0100)  node-red-test  27 Nov 22:18:07 - [info] Flows file     : /data/flows.json
27.11.18 23:18:07 (+0100)  node-red-test  27 Nov 22:18:07 - [info] Server now running at http://127.0.0.1:1880/node-red-test/
27.11.18 23:18:07 (+0100)  node-red-test  27 Nov 22:18:07 - [warn]
27.11.18 23:18:07 (+0100)  node-red-test
27.11.18 23:18:07 (+0100)  node-red-test  ---------------------------------------------------------------------
27.11.18 23:18:07 (+0100)  node-red-test  Your flow credentials file is encrypted using a system-generated key.
27.11.18 23:18:07 (+0100)  node-red-test
27.11.18 23:18:07 (+0100)  node-red-test  If the system-generated key is lost for any reason, your credentials
27.11.18 23:18:07 (+0100)  node-red-test  file will not be recoverable, you will have to delete it and re-enter
27.11.18 23:18:07 (+0100)  node-red-test  your credentials.
27.11.18 23:18:07 (+0100)  node-red-test
27.11.18 23:18:07 (+0100)  node-red-test  You should set your own key using the 'credentialSecret' option in
27.11.18 23:18:07 (+0100)  node-red-test  your settings file. Node-RED will then re-encrypt your credentials
27.11.18 23:18:07 (+0100)  node-red-test  file using your chosen key the next time you deploy a change.
27.11.18 23:18:07 (+0100)  node-red-test  ---------------------------------------------------------------------
27.11.18 23:18:07 (+0100)  node-red-test
27.11.18 23:18:07 (+0100)  node-red-test  27 Nov 22:18:07 - [info] Starting flows
27.11.18 23:18:08 (+0100)  node-red-test  27 Nov 22:18:08 - [info] Started flows
27.11.18 23:18:08 (+0100)  node-red-test  27 Nov 22:18:08 - [info] [mqtt-broker:mqtt broker] Connected to broker: mqtt://mqtt:1883
27.11.18 23:18:10 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:10 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:10 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:10 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:10 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:10 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:10 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:10 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:10 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:10 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:10 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:10 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:10 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:10 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:10 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:10 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:10 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:10 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:10 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:10 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:10 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:10 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:10 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:10 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:10 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:10 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:10 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:10 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:10 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:10 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:10 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:10 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:10 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:12 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:12 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:12 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:12 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:12 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:12 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:12 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:12 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:12 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:12 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:12 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:12 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:12 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:12 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:12 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:12 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:12 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:12 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:12 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:12 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:12 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:12 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:12 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:12 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:12 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:12 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:12 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:12 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:12 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:12 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:12 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:12 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:12 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:14 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:14 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:14 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:14 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:14 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:14 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:14 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:14 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:14 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:14 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:14 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:14 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:14 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:14 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:14 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:14 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:14 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:14 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:14 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:14 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:14 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:14 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:14 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:14 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:14 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:14 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:14 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:14 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:14 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:14 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:14 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:14 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:14 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:16 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:16 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:16 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:16 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:16 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:16 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:16 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:16 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:16 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:16 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:16 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:16 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:16 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:16 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:16 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:16 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:16 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:16 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:16 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:16 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:16 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:16 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:16 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:16 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:16 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:16 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:16 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:16 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:16 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:16 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:16 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:16 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:16 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:18 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:18 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:18 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:18 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:18 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:18 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:18 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:18 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:18 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:18 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:18 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:18 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:18 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:18 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:18 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:18 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:18 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:18 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:18 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:18 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:18 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:18 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:18 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:18 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:18 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:18 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:18 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:18 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:18 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:18 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:18 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:18 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:18 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:20 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:20 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:20 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:20 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:20 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:20 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:20 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:20 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:20 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:20 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:20 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:20 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:20 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:20 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:20 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:20 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:20 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:20 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:20 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:20 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:20 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:20 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:20 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:20 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:20 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:20 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:20 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:20 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:20 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:20 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:20 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:20 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:20 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:22 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:22 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:22 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:22 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:22 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:22 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:22 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:22 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:22 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:22 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:22 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:22 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:22 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:22 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:22 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:22 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:22 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:22 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:22 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:22 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:22 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:22 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:22 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:22 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:22 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:22 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:22 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:22 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:22 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:22 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:22 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:22 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:22 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:24 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:24 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:24 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:24 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:24 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:24 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:24 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:24 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:24 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:24 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:24 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:24 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:24 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:24 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:24 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:24 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:24 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:24 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:24 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:24 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:24 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:24 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:24 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:24 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:24 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:24 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:24 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:24 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:24 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:24 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:24 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:24 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:24 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:26 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:26 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:26 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:26 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:26 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:26 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:26 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:26 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:26 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:26 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:26 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:26 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:26 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:26 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:26 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:26 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:26 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:26 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:26 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:26 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:26 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:26 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:26 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:26 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:26 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:26 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:26 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:26 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:26 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:26 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:26 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:26 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:26 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:28 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:28 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:28 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:28 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:28 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:28 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:28 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:28 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:28 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:28 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:28 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:28 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:28 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:28 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:28 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:28 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:28 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:28 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:28 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:28 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:28 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:28 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:28 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:28 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:28 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:28 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:28 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:28 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:28 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:28 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:28 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:28 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:28 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16
27.11.18 23:18:30 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:30 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:30 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:30 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:30 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:30 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:30 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:30 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:30 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:30 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:30 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:30 (+0100)  node-red-test  Error: Can't set headers after they are sent.
27.11.18 23:18:30 (+0100)  node-red-test      at validateHeader (_http_outgoing.js:504:11)
27.11.18 23:18:30 (+0100)  node-red-test      at ServerResponse.setHeader (_http_outgoing.js:511:3)
27.11.18 23:18:30 (+0100)  node-red-test      at expressInit (/usr/src/node-red/node_modules/express/lib/middleware/init.js:30:42)
27.11.18 23:18:30 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:30 (+0100)  node-red-test      at trim_prefix (/usr/src/node-red/node_modules/express/lib/router/index.js:317:13)
27.11.18 23:18:30 (+0100)  node-red-test      at /usr/src/node-red/node_modules/express/lib/router/index.js:284:7
27.11.18 23:18:30 (+0100)  node-red-test      at Function.process_params (/usr/src/node-red/node_modules/express/lib/router/index.js:335:12)
27.11.18 23:18:30 (+0100)  node-red-test      at next (/usr/src/node-red/node_modules/express/lib/router/index.js:275:10)
27.11.18 23:18:30 (+0100)  node-red-test      at query (/usr/src/node-red/node_modules/express/lib/middleware/query.js:45:5)
27.11.18 23:18:30 (+0100)  node-red-test      at Layer.handle [as handle_request] (/usr/src/node-red/node_modules/express/lib/router/layer.js:95:5)
27.11.18 23:18:30 (+0100)  node-red-test  Error: Can't render headers after they are sent to the client
27.11.18 23:18:30 (+0100)  node-red-test      at ServerResponse.writeHead (_http_server.js:214:15)
27.11.18 23:18:30 (+0100)  node-red-test      at XHR.Polling.onPollRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:85:9)
27.11.18 23:18:30 (+0100)  node-red-test      at XHR.Polling.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling.js:65:10)
27.11.18 23:18:30 (+0100)  node-red-test      at XHR.onRequest (/usr/src/node-red/node_modules/engine.io/lib/transports/polling-xhr.js:46:33)
27.11.18 23:18:30 (+0100)  node-red-test      at /usr/src/node-red/node_modules/engine.io/lib/server.js:230:46
27.11.18 23:18:30 (+0100)  node-red-test      at Server.verify (/usr/src/node-red/node_modules/engine.io/lib/server.js:171:3)
27.11.18 23:18:30 (+0100)  node-red-test      at Server.handleRequest (/usr/src/node-red/node_modules/engine.io/lib/server.js:222:8)
27.11.18 23:18:30 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/engine.io/lib/server.js:467:14)
27.11.18 23:18:30 (+0100)  node-red-test      at Server.<anonymous> (/usr/src/node-red/node_modules/socket.io/lib/index.js:343:16)
27.11.18 23:18:30 (+0100)  node-red-test      at /usr/src/node-red/node_modules/appmetrics-dash/lib/appmetrics-dash.js:197:16

[janvda]

This might be a similar problem as #151

[ddresch]

Same issue here. I tried multiple node versions no difference.

[elasticroentgen]

Had the same issue when using .attach() along with .monitor()
I removed it and only kept .monitor()

Seems to work fine that way.

[knolleary]

Hi - is there anything we can do to help resolve this? It has been a long standing issue and we (in the Node-RED project) keep getting asked why it isn't working.

[chameleonbr]

@knolleary I was able to make appmetrics work on nodered just like this:

var dash = require('appmetrics-dash');
dash.monitor({port:3335}); // different port 

And making NodeRED running on the different port.
Taking advantage of the issue, In nodered, there is a way to capture a node's input and output events and throw this to something like jaeger?