How to get the Dns Time from the ligthhouse reports.??

[ashwinrajanta]

Does google lighthouse report the dns timings in the lighthouse report? if so how to retrieve the values??
Note. Running the lighthouse via cli inside a docker

[ashwinrajanta]

if not directly also. can it derived based on some calculations?

[adamraine]

DNS timings are not included in the report

[ashwinrajanta]

defaultPass.devtoolslog.json

@adamraine thanks for responding.. But after execution there is a directory created called "latest-run" and inside that few files are created. in one of these files if you see i could see "Network.responseReceived", there i could see something called dnsStart dnsEnd params

What is that.? i have attached the sample json file

{"method":"Network.responseReceived","params":{"requestId":"79CAF8387324785A8E2CFE5289FFA15E","loaderId":"79CAF8387324785A8E2CFE5289FFA15E","timestamp":379.08508,"type":"Document","response":{"url":"https://www.facebook.com/","status":200,"statusText":"OK","headers":{"Cache-Control":"private, no-cache, no-store, must-revalidate","Connection":"keep-alive","Content-Encoding":"br","Content-Type":"text/html; charset=\"utf-8\"","Date":"Fri, 06 Oct 2023 00:42:35 GMT","Expires":"Sat, 01 Jan 2000 00:00:00 GMT","Pragma":"no-cache","Strict-Transport-Security":"max-age=15552000; preload","Transfer-Encoding":"chunked","Vary":"Accept-Encoding","X-Content-Type-Options":"nosniff","X-FB-Debug":"Nyn/HxSuTNPan0hhH63/K0m0hydokNX3PiAsEKt1QNSCsW7QR0cccThYW0h7/PN5oGRLn9+xEboIxTvzlhW2Eg==","X-Frame-Options":"DENY","X-XSS-Protection":"0","content-security-policy":"default-src data: blob: 'self' https://*.fbsbx.com 'unsafe-inline' *.facebook.com *.fbcdn.net 'unsafe-eval';script-src *.facebook.com *.fbcdn.net *.facebook.net *.google-analytics.com *.google.com 127.0.0.1:* 'unsafe-inline' blob: data: 'self' connect.facebook.net 'unsafe-eval';style-src fonts.googleapis.com *.fbcdn.net data: *.facebook.com 'unsafe-inline';connect-src *.facebook.com facebook.com *.fbcdn.net *.facebook.net wss://*.facebook.com:* wss://*.whatsapp.com:* wss://*.fbcdn.net attachment.fbsbx.com ws://localhost:* blob: *.cdninstagram.com 'self' http://localhost:3103 wss://gateway.facebook.com wss://edge-chat.facebook.com wss://snaptu-d.facebook.com wss://kaios-d.facebook.com/ v.whatsapp.net *.fbsbx.com *.fb.com;font-src data: *.gstatic.com *.facebook.com *.fbcdn.net *.fbsbx.com;img-src *.fbcdn.net *.facebook.com data: https://*.fbsbx.com *.tenor.co media.tenor.com facebook.com *.cdninstagram.com fbsbx.com fbcdn.net *.giphy.com connect.facebook.net *.carriersignal.info blob: android-webview-video-poster: googleads.g.doubleclick.net www.googleadservices.com *.whatsapp.net *.fb.com *.oculuscdn.com;media-src *.cdninstagram.com blob: *.fbcdn.net *.fbsbx.com www.facebook.com *.facebook.com https://*.giphy.com data:;frame-src *.doubleclick.net *.google.com *.facebook.com www.googleadservices.com *.fbsbx.com fbsbx.com data: www.instagram.com *.fbcdn.net https://paywithmybank.com https://sandbox.paywithmybank.com;worker-src blob: *.facebook.com data:;block-all-mixed-content;upgrade-insecure-requests;","cross-origin-opener-policy":"unsafe-none","cross-origin-resource-policy":"cross-origin","document-policy":"force-load-at-top","nel":"{\"report_to\":\"network-errors\",\"max_age\":3600,\"failure_fraction\":0.01}","origin-agent-cluster":"?0","permissions-policy":"accelerometer=(), ambient-light-sensor=(), bluetooth=(), camera=(self), geolocation=(self), gyroscope=(), hid=(), idle-detection=(), magnetometer=(), microphone=(self), midi=(), payment=(), screen-wake-lock=(), serial=(), usb=()","report-to":"{\"max_age\":259200,\"endpoints\":[{\"url\":\"https:\\/\\/www.facebook.com\\/ajax\\/browser_error_reports\\/?device_level=unknown\"}]}, {\"max_age\":3600,\"endpoints\":[{\"url\":\"https:\\/\\/www.facebook.com\\/ajax\\/browser_error_reports\\/?device_level=unknown\"}],\"group\":\"network-errors\"}"},"mimeType":"text/html","connectionReused":false,"connectionId":13,"remoteIPAddress":"157.240.198.35","remotePort":443,"fromDiskCache":false,"fromServiceWorker":false,"fromPrefetchCache":false,"encodedDataLength":3204,"timing":{"requestTime":378.622949,"proxyStart":-1,"proxyEnd":-1,"dnsStart":18.463,"dnsEnd":50.546,"connectStart":50.546,"connectEnd":114.922,"sslStart":57.612,"sslEnd":114.903,"workerStart":-1,"workerReady":-1,"workerFetchStart":-1,"workerRespondWithSettled":-1,"sendStart":115.015,"sendEnd":115.193,"pushStart":0,"pushEnd":0,"receiveHeadersStart":459.774,"receiveHeadersEnd":460.543},"responseTime":1696552955713.872,"protocol":"http/1.1","alternateProtocolUsage":"unspecifiedReason","securityState":"insecure","securityDetails":{"protocol":"TLS 1.3","keyExchange":"","keyExchangeGroup":"X25519","cipher":"AES_256_GCM","certificateId":0,"subjectName":"*.facebook.com","sanList":["*.facebook.com","facebook.com"],"issuer":"ca.intelsat.goskope.com","validFrom":1693112699,"validTo":1727240699,"signedCertificateTimestampList":[],"certificateTransparencyCompliance":"unknown","serverSignatureAlgorithm":2052,"encryptedClientHello":false}},"hasExtraInfo":true,"frameId":"8A2E11E91542C395A8A433D685E752D2"},"targetType":"page","sessionId":"D6FFEDDCD6744C8F9B3DDC66642B5EE2"},

[benschwarz]

@ashwinrajanta As @adamraine said in a previous reply, Lighthouse does not include DNS timing information. Timing information is available in the remote debugging API (as you've demonstrated above).

However, Lighthouse by default loads pages at full network speed, and then applies network simulation in order to calculate metrics and network timing information. While you can access the timing information from the API (as above), it will represent the unthrottled load, and not the simulated load time.

That's why there's no DNS timings in the report, and afaik why there won't be in the near future.