Getting chrome performance and tracing logs

Question

I'm trying to follow the idea suggested in the Web Performance Testing with WebDriver google test automation conference talk and ChromeDriver "Performance Log" documentation page to get the trace data which I want to submit to webpagetest for performance analysis later.

How can I retrieve performance logs using python selenium bindings?

---

I've tried to print out log_types available in the driver instance

from selenium import webdriver

driver = webdriver.Chrome()
driver.get('https://stackoverflow.com')

print driver.log_types

driver.close()

but got only

[u'browser', u'driver']

And I don't see a relevant command-line switch.

Answer 1

Performance logs are disabled by default.

To enable it, use DesiredCapabilities and configure loggingPrefs:

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities

caps = DesiredCapabilities.CHROME
 #as per latest docs
caps['goog:loggingPrefs'] = {'performance': 'ALL'}
driver = webdriver.Chrome(desired_capabilities=caps)

driver.get('https://stackoverflow.com')

for entry in driver.get_log('performance'):
    print(entry)

driver.quit()

This results into a bunch of tracing log entries printed on the console:

{u'timestamp': 1419487459178, u'message': u'{"message":{"method":"Network.responseReceived","params":{"frameId":"2105.1","loaderId":"2105.2","requestId":"2105.1","response":{"connectionId":0,"connectionReused":false,"encodedDataLength":-1,"fromDiskCache":false,"fromServiceWorker":false,"headers":{"Access-Control-Allow-Origin":"*","Content-Type":"text/plain;charset=US-ASCII"},"mimeType":"text/plain","status":200,"statusText":"OK","url":"data:,"},"timestamp":1419487458.92934,"type":"Document"}},"webview":"2C66E956-A48B-456B-8A4E-1022F699AA92"}', u'level': u'INFO'}
{u'timestamp': 1419487459178, u'message': u'{"message":{"method":"Network.loadingFinished","params":{"encodedDataLength":0,"requestId":"2105.1","timestamp":1419487458.92936}},"webview":"2C66E956-A48B-456B-8A4E-1022F699AA92"}', u'level': u'INFO'}
{u'timestamp': 1419487459178, u'message': u'{"message":{"method":"Page.frameNavigated","params":{"frame":{"id":"2105.1","loaderId":"2105.2","mimeType":"text/plain","securityOrigin":"://","url":"data:,"}}},"webview":"2C66E956-A48B-456B-8A4E-1022F699AA92"}', u'level': u'INFO'}
...