time.to_first_byte
RTIME, read-only.
The time interval since the request started up to the point before the
vcl_deliver subroutine ran. When used in a string context, an RTIME variable like
this one will be formatted as a number in seconds with 3 decimal digits of
precision. In vcl_deliver this interval will be very close to
time.elapsed. In vcl_log,
the difference between time.elapsed
and time.to_first_byte will be the time that it took to send the response body.
Try it out
time.to_first_byte is used in the following code examples. Examples apply VCL to real-world use cases and can be deployed as they are, or adapted for your own service. See the full list of code examples for more inspiration.
Click RUN on a sample below to provision a Fastly service, execute the code on Fastly, and see how the function behaves.
Comprehensive logging
Fastly offers a myriad of different variables that you can log. See and test a large collection here.