Varnish 4 X-Request-Start Header for New Relic Queue Time Reporting

varnish4-newrelic-x-request-start.vcl

# To allow inline-C in VCL start varnishd with -p vcc_allow_inline_c=on
C{
    #include <sys/time.h>
    #include <stdio.h>
    static const struct gethdr_s VGC_HDR_REQ_reqstart = { HDR_REQ, "\020X-Request-Start:" };
}C

sub vcl_recv {
    # Add X-Request-Start header for New Relic queue time analytics
    C{
        struct timeval detail_time;
        gettimeofday(&detail_time, NULL);
        char start[20];
        sprintf(start, "t=%lu%06lu", detail_time.tv_sec, detail_time.tv_usec);
        VRT_SetHdr(ctx, &VGC_HDR_REQ_reqstart, start, vrt_magic_string_end);
    }C
}

Add X-Request-Start Header in Varnish 4.x

Based on Varnish 3.x snippet from Tracking request queue time on New Relic RPM with Varnish comment by Disqus user Marcelo IH.

To allow inline-C in the VCL start Varnish with: varnishd -p vcc_allow_inline_c=on

You can check if it works by looking at: varnishtop -I ReqHeader:X-Request-Start

Nice, thnx!