nixbld: refactor hydra-www-outputs to generate etags for nginx

Should again resolve Gitea issue #12

nixbld-etc-nixos/configuration.nix

@@ -4,14 +4,12 @@
 
 { config, pkgs, ... }:
 
-let
-  hydraWwwOutputs = "/var/www/hydra-outputs";
-in
 {
   imports =
     [ # Include the results of the hardware scan.
       ./hardware-configuration.nix
       ./homu/nixos-module.nix
+      ./hydra-www-outputs.nix
     ];
 
   # Use the systemd-boot EFI boot loader.
@@ -139,25 +137,20 @@ ACTION=="add", SUBSYSTEM=="tty", \
       ''
       binary_cache_secret_key_file = /etc/nixos/secret/nixbld.m-labs.hk-1
       max_output_size = 5500000000
-
-      <runcommand>
-        job = artiq:main:artiq-manual-html
-        command = ln -sf $(jq -r '.outputs[0].path' < $HYDRA_JSON) ${hydraWwwOutputs}/artiq-manual-html-beta
-      </runcommand>
-      <runcommand>
-        job = artiq:main:artiq-manual-latexpdf
-        command = ln -sf $(jq -r '.outputs[0].path' < $HYDRA_JSON) ${hydraWwwOutputs}/artiq-manual-latexpdf-beta
-      </runcommand>
       '';
   };
-  systemd.services.hydra-www-outputs-init = {
-    description = "Set up a hydra-owned directory for build outputs";
-    wantedBy = [ "multi-user.target" ];
-    requiredBy = [ "hydra-queue-runner.service" ];
-    before = [ "hydra-queue-runner.service" ];
-    serviceConfig = {
-      Type = "oneshot";
-      ExecStart = [ "${pkgs.coreutils}/bin/mkdir -p ${hydraWwwOutputs}" "${pkgs.coreutils}/bin/chown hydra-queue-runner:hydra ${hydraWwwOutputs}" ];
+  services.hydraWwwOutputs = {
+    "m-labs.hk" = {
+      "artiq-manual-beta-html" = {
+        job = "artiq:main:artiq-manual-html";
+        httpPath = "/artiq/manual-beta";
+        outputPath = "share/doc/artiq-manual/html";
+      };
+      "artiq-manual-beta-latexpdf" = {
+        job = "artiq:main:artiq-manual-latexpdf";
+        httpPath = "/artiq/manual-beta.pdf";
+        outputPath = "share/doc/artiq-manual/ARTIQ.pdf";
+      };
     };
   };
 
@@ -230,8 +223,6 @@ ACTION=="add", SUBSYSTEM=="tty", \
         locations."/gateware.html".extraConfig = ''
           return 301 /migen/;
         '';
-        locations."/artiq/manual-beta".alias = "${hydraWwwOutputs}/artiq-manual-html-beta/share/doc/artiq-manual/html";
-        locations."/artiq/manual-beta.pdf".alias = "${hydraWwwOutputs}/artiq-manual-latexpdf-beta/share/doc/artiq-manual/ARTIQ.pdf";
       };
       "www.m-labs.hk" = {
         addSSL = true;

nixbld-etc-nixos/hydra-www-hook.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+
+set -e
+
+# Argument 1:
+CONF=$1
+# Argument 2: HTTP location
+LOCATION=$2
+# Argument 3: HTTP alias target within the derivation output
+HTTP_PATH=$3
+# Get path of first output
+OUTPUT=$(jq -r '.outputs[0].path' < $HYDRA_JSON)
+HASH=${OUTPUT:11:32}
+ROOT="$OUTPUT/$HTTP_PATH"
+
+cat > $CONF <<EOF
+location $LOCATION {
+         alias $ROOT;
+
+         # Do not generate Etags from /nix/store's 1970 timestamps.
+         etag off;
+         add_header etag "\"$HASH\"";
+}
+EOF
+
+/run/wrappers/bin/sudo systemctl reload nginx

nixbld-etc-nixos/hydra-www-outputs.nix

@@ -0,0 +1,94 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+let
+  hookPkg =
+    { stdenv, makeWrapper, bash, coreutils, jq }:
+    stdenv.mkDerivation rec {
+      name = "hydra-www-hook";
+      src = ./.;
+      buildInputs = [ makeWrapper ];
+      propagatedBuildInputs = [ bash coreutils jq ];
+      phases = [ "unpackPhase" "installPhase" "fixupPhase" ];
+      installPhase = ''
+        mkdir -p $out/bin/
+        cp hydra-www-hook.sh $out/bin/
+        wrapProgram $out/bin/hydra-www-hook.sh \
+          --prefix PATH : ${makeBinPath propagatedBuildInputs}
+      '';
+    };
+  hook = pkgs.callPackage hookPkg {};
+
+  hydraWwwOutputs = "/var/www/hydra-outputs";
+  cfg = config.services.hydraWwwOutputs;
+in
+{
+  options.services.hydraWwwOutputs = mkOption {
+    type = with types; attrsOf (attrsOf (submodule {
+      options = {
+        job = mkOption {
+          type = string;
+        };
+        httpPath = mkOption {
+          type = string;
+        };
+        outputPath = mkOption {
+          type = string;
+        };
+      };
+    }));
+  };
+
+  config.services.hydra = {
+    extraConfig = builtins.concatStringsSep "\n"
+      (builtins.concatMap (vhost:
+        builtins.attrValues (
+          builtins.mapAttrs (name: cfg: ''
+            <runcommand>
+              job = ${cfg.job}
+              command = ${hook}/bin/hydra-www-hook.sh ${hydraWwwOutputs}/${name}.conf ${cfg.httpPath} ${cfg.outputPath}
+            </runcommand>
+          '') cfg.${vhost}
+        )) (builtins.attrNames cfg)
+      );
+  };
+
+  config.systemd.services.hydra-www-outputs-init = {
+    description = "Set up a hydra-owned directory for build outputs";
+    wantedBy = [ "multi-user.target" ];
+    requiredBy = [ "hydra-queue-runner.service" ];
+    before = [ "hydra-queue-runner.service" ];
+    serviceConfig = {
+      Type = "oneshot";
+      ExecStart = [
+        "${pkgs.coreutils}/bin/mkdir -p ${hydraWwwOutputs}"
+        ] ++
+        (builtins.concatMap (vhost:
+          map (name:
+            "${pkgs.coreutils}/bin/touch ${hydraWwwOutputs}/${name}.conf"
+          ) (builtins.attrNames cfg.${vhost})
+        ) (builtins.attrNames cfg)) ++ [
+          "${pkgs.coreutils}/bin/chown -R hydra-queue-runner:hydra ${hydraWwwOutputs}"
+        ];
+    };
+  };
+
+  # Allow the hook to reload nginx
+  config.security.sudo.extraRules = [ {
+    users = [ "hydra-queue-runner" ];
+    commands = [ {
+      command = "${config.systemd.package}/bin/systemctl reload nginx";
+      options = [ "NOPASSWD" ];
+    } ];
+  } ];
+
+  config.services.nginx = {
+    virtualHosts = builtins.mapAttrs (vhost: cfg': {
+      extraConfig = builtins.concatStringsSep "\n" (
+        map (name:
+          "include ${hydraWwwOutputs}/${name}.conf;"
+        ) (builtins.attrNames cfg')
+      );
+    }) cfg;
+  };
+}