nixpkgs/nixos/tests/proxy.nix

import ./make-test-python.nix (
  { pkgs, ... }:

  let
    backend =
      { pkgs, ... }:
      {
        services.httpd = {
          enable = true;
          adminAddr = "foo@example.org";
          virtualHosts.localhost.documentRoot = "${pkgs.valgrind.doc}/share/doc/valgrind/html";
        };
        networking.firewall.allowedTCPPorts = [ 80 ];
      };
  in
  {
    name = "proxy";
    meta = with pkgs.lib.maintainers; {
      maintainers = [ ];
    };

    nodes = {
      proxy =
        { nodes, ... }:
        {
          services.httpd = {
            enable = true;
            adminAddr = "bar@example.org";
            extraModules = [
              "proxy_balancer"
              "lbmethod_byrequests"
            ];
            extraConfig = ''
              ExtendedStatus on
            '';
            virtualHosts.localhost = {
              extraConfig = ''
                <Location /server-status>
                  Require all granted
                  SetHandler server-status
                </Location>

                <Proxy balancer://cluster>
                  Require all granted
                  BalancerMember http://${nodes.backend1.config.networking.hostName} retry=0
                  BalancerMember http://${nodes.backend2.config.networking.hostName} retry=0
                </Proxy>

                ProxyStatus       full
                ProxyPass         /server-status !
                ProxyPass         /       balancer://cluster/
                ProxyPassReverse  /       balancer://cluster/

                # For testing; don't want to wait forever for dead backend servers.
                ProxyTimeout      5
              '';
            };
          };
          networking.firewall.allowedTCPPorts = [ 80 ];
        };

      backend1 = backend;
      backend2 = backend;

      client = { ... }: { };
    };

    testScript = ''
      start_all()

      proxy.wait_for_unit("httpd")
      backend1.wait_for_unit("httpd")
      backend2.wait_for_unit("httpd")
      client.wait_for_unit("network.target")

      # With the back-ends up, the proxy should work.
      client.succeed("curl --fail http://proxy/")

      client.succeed("curl --fail http://proxy/server-status")

      # Block the first back-end.
      backend1.block()

      # The proxy should still work.
      client.succeed("curl --fail http://proxy/")
      client.succeed("curl --fail http://proxy/")

      # Block the second back-end.
      backend2.block()

      # Now the proxy should fail as well.
      client.fail("curl --fail http://proxy/")

      # But if the second back-end comes back, the proxy should start
      # working again.
      backend2.unblock()
      client.succeed("curl --fail http://proxy/")
    '';
  }
)