nginx: build offline documentation

pkgs/servers/http/nginx/generic.nix

@@ -1,4 +1,5 @@
 { lib, stdenv, fetchurl, fetchpatch, openssl, zlib, pcre, libxml2, libxslt
+, fetchhg
 
 , nixosTests
 , substituteAll, gd, geoip, perl
@@ -16,6 +17,19 @@
 , nginxVersion ? version
 , src ? null # defaults to upstream nginx ${version}
 , sha256 ? null # when not specifying src
+
+# Upstream maintains documentation (sources of https://nginx.org) in separate
+# mercurial repository, which do not correspond to particular git commit, but at
+# least has "introduced in version X.Y" comments.
+#
+# In other words, documentation does not necessary matches capabilities of
+# $out/bin/nginx, but we have no better options.
+, srcDoc ? fetchhg {
+    url = "https://hg.nginx.org/nginx.org";
+    sha256 = "029n4mnmjw94h01qalmjgf1c2h3h7wm798xv5knk3padxiy4m28b";
+    rev = "a3aee2697d4e";
+  }
+, extraPatchesDoc ? [ ./nginx-doc.patch ]
 , configureFlags ? []
 , buildInputs ? []
 , extraPatches ? []
@@ -23,6 +37,7 @@
 , preConfigure ? ""
 , postInstall ? null
 , meta ? null
+, nginx-doc ? outer.nginx-doc
 , passthru ? { tests = {}; }
 }:
 
@@ -37,6 +52,31 @@ let
         if supports nginxVersion then mod.${attrPath} or []
         else throw "Module at ${toString mod.src} does not support nginx version ${nginxVersion}!");
 
+  # Output of this derivation is copied into $doc of resulting nginx to save on
+  # building time, since we have multiple nginx versions, but only one version
+  # of documentation.
+  #
+  # As such, this derivation never appears in user profile, so its name and
+  # compliance to conventions is not important.
+  documentation = stdenv.mkDerivation {
+    name = "nginx-doc";
+    src = srcDoc;
+    patches = extraPatchesDoc;
+    nativeBuildInputs = [ libxslt libxml2 ];
+
+    # Generated documentation is not local-friendly, since it assumes that link to directory
+    # is the same as link to index.html in that directory, which is not how browsers behave
+    # with local filesystem.
+    #
+    # TODO: patch all relative links that do not end with .html.
+
+    # /en subdirectory must exist, relative links expect it.
+    installPhase = ''
+      mkdir -p $out/share/doc/nginx
+      mv libxslt/en $out/share/doc/nginx
+    '';
+  };
+
 in
 
 stdenv.mkDerivation {
@@ -44,6 +84,8 @@ stdenv.mkDerivation {
   inherit version;
   inherit nginxVersion;
 
+  outputs = ["out" "doc"];
+
   src = if src != null then src else fetchurl {
     url = "https://nginx.org/download/nginx-${version}.tar.gz";
     inherit sha256;
@@ -114,8 +156,12 @@ stdenv.mkDerivation {
 
   configurePlatforms = [];
 
-  preConfigure = preConfigure
-    + concatMapStringsSep "\n" (mod: mod.preConfigure or "") modules;
+  # Disable _multioutConfig hook which adds --bindir=$out/bin into configureFlags,
+  # which breaks build, since nginx does not actually use autoconf.
+  preConfigure = ''
+    setOutputFlags=
+  '' + preConfigure
+     + concatMapStringsSep "\n" (mod: mod.preConfigure or "") modules;
 
   patches = map fixPatch ([
     (substituteAll {
@@ -145,6 +191,11 @@ stdenv.mkDerivation {
 
   enableParallelBuilding = true;
 
+  preInstall = ''
+    mkdir -p $doc
+    cp -r ${documentation}/* $doc
+  '';
+
   postInstall = if postInstall != null then postInstall else ''
     mv $out/sbin $out/bin
   '';

pkgs/servers/http/nginx/nginx-doc.patch

@@ -0,0 +1,29 @@
+Kill google analytics from local documentation.
+
+diff -r bb0a2fbdc886 xslt/ga.xslt
+--- a/xslt/ga.xslt	Mon Apr 06 11:17:11 2020 +0100
++++ b/xslt/ga.xslt	Thu Apr 09 10:29:02 2020 -0400
+@@ -6,23 +6,6 @@
+ <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
+ 
+ <xsl:template name="ga">
+-
+-    <script>
+-        (function(w, d, s, l, i) {
+-            w[l] = w[l] || [];
+-            w[l].push({
+-                'gtm.start': new Date().getTime(),
+-                event: 'gtm.js'
+-            });
+-            var f = d.getElementsByTagName(s)[0],
+-                j = d.createElement(s),
+-                dl = l != 'dataLayer' ? '&amp;l=' + l : '';
+-            j.async = true;
+-            j.src = '//www.googletagmanager.com/gtm.js?id=' + i + dl;
+-            f.parentNode.insertBefore(j, f);
+-        })(window, document, 'script', 'dataLayer', 'GTM-TPSP33');
+-    </script>
+-
+ </xsl:template>
+ 
+ </xsl:stylesheet>