Patch nginx configurations to add quic listeners and use new http2 directive.

patch_nginx_listeners.py

#!/usr/bin/env python3

import os
import re
import sys
import argparse


def modify(path, args):
    print("DO: ", path)
    lines = []
    with open(path, "r") as f:
        http2 = False
        need_http3 = set()
        h3_port = None
        ident = ""
        for l in f.readlines():
            ll = l.strip()
            if ll.startswith("listen"):
                if not ident:
                    ident = re.findall("^(\s+)", l)[0]

                p = re.findall("listen\s*([^\s]+)", ll)[0]
                if "quic" in l:
                    if p in need_http3:
                        need_http3.remove(p)
                elif "ssl" in l:
                    need_http3.add(p)
                if ("quic" in l or "ssl" in l) and not "unix:" in p and not h3_port:
                    port = re.findall("(?:^|:)(\d+)$", p.split()[0])[0]
                    h3_port = port
                if "http2" in l:
                    http2 = True
                    l = l.replace(" http2", "")
                    print("~ " + l.strip())
            elif ll.startswith("http2 on"):
                http2 = False
            elif ll:
                if http2 and not args.noh2:
                    lines.append(ident + "http2 on;\n")
                    print("+ http2 on;")
                suffix = ""
                if os.path.basename(path) == "default":
                    suffix = " default_server reuseport";
                if not args.noh3l:
                    for h in need_http3:
                        lines.append(ident + "listen " + h + " quic" + suffix + ";\n")
                        print("+ listen " + h + " quic" + suffix + ";")
                if h3_port and not args.noh3a:
                    lines.append(ident + "add_header Alt-Svc 'h3=\":%s\"; ma=86400';\n" % port)
                    print("add_header Alt-Svc 'h3=\":%s\"; ma=86400';\n" % port)

                http2 = False
                need_http3 = set()
                h3_port = None

                if ("$http_host" in l or "ngx.var.http_host" in l) and not args.nohost:
                    l = l.replace("$http_host", "$host")
                    l = l.replace("ngx.var.http_host", "ngx.var.host")
                    print("~ " + l.strip())

            lines.append(l)

    if not args.force:
        return

    with open(path, "w") as f:
        f.write("".join(lines))

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument('-f', '--force', action='store_true', default=False, help="actually write to files")
    parser.add_argument("path", help="directory containing all confs (not recursive)", default="/etc/nginx/sites-enabled")
    parser.add_argument('--no-h3-listen', dest="noh3l", action='store_true', default=False, help="don't add new quic listen directives")
    parser.add_argument('--no-h3-alt-svc', dest="noh3a", action='store_true', default=False, help="don't add new quic add_header directives")
    parser.add_argument('--no-h2-conversion', dest="noh2", action='store_true', default=False, help="don't convert new http2 directives")
    parser.add_argument('--no-host-conversion', dest="nohost", action='store_true', default=False, help="don't convert $http_host to $host")
    args = parser.parse_args()
    if args.force:
        print("not DRY")
    for path in os.listdir(args.path):
        if path.startswith("."):
            continue
        modify(os.path.join(args.path, path), args)