Call the custom-defined JWT VCL procedure that checks the validity of a JSON Web Token. This VCL snippet requires vmod_digest and https://gist.github.com/ThijsFeryn/b745c42dbfa328d702b8dbba8777aee2

call_jwt.vcl

vcl 4.0;

import digest;

backend default {
    .host = "localhost";
    .port = "8080";
}

include "jwt.vcl";

sub vcl_recv {
    if ((req.method != "GET" && req.method != "HEAD") || req.http.Authorization) {
        return (pass);
    }
    call jwt;
    if(req.url == "/private" && req.http.X-Login != "true") {
        return(synth(302,"/login"));
    }
    return(hash);
}

sub vcl_synth {
    if (resp.status == 301 || resp.status == 302) {
        set resp.http.location = resp.reason;
        set resp.reason = "Moved";
        return (deliver);
    }
}