Patch Gerrit's build system for webfont free war builds

Gerrit grew the ability to build webfont free documentation but this
wasn't extended to the release war builds. Add a new
release_webfont_free war release target that does build without webfonts
via a local patch against gerrit then build using that.

If this is successful we should reduce the number of external resources
needed by Gerrit (a win for our users) and we can work with upstream to
see about merging functionality that allows us to do this without a
special patch.

Change-Id: I0cb31a8ce98cb307aeafbb131ea073a3c887b3c4

docker/gerrit/patches/webfont_free.patch

@@ -0,0 +1,62 @@
+diff --git a/BUILD b/BUILD
+index 0c10d76fe2..c70e989670 100644
+--- a/BUILD
++++ b/BUILD
+@@ -34,6 +34,13 @@ pkg_war(
+     doc = True,
+ )
+ 
++pkg_war(
++    name = "release_webfont_free",
++    context = ["//plugins:core"],
++    doc = True,
++    doc_webfont = False,
++)
++
+ pkg_war(
+     name = "withdocs",
+     doc = True,
+diff --git a/Documentation/BUILD b/Documentation/BUILD
+index 85ddbe7413..3c22e37773 100644
+--- a/Documentation/BUILD
++++ b/Documentation/BUILD
+@@ -118,6 +118,15 @@ genasciidoc_zip(
+     directory = DOC_DIR,
+ )
+ 
++genasciidoc_zip(
++    name = "html_webfont_free",
++    srcs = SRCS,
++    attributes = documentation_attributes(),
++    backend = "html5",
++    directory = DOC_DIR,
++    webfonts = False,
++)
++
+ genasciidoc_zip(
+     name = "searchfree",
+     srcs = SRCS,
+diff --git a/tools/bzl/pkg_war.bzl b/tools/bzl/pkg_war.bzl
+index 4792de2f2a..fd5d455349 100644
+--- a/tools/bzl/pkg_war.bzl
++++ b/tools/bzl/pkg_war.bzl
+@@ -150,14 +150,17 @@ _pkg_war = rule(
+     implementation = _war_impl,
+ )
+ 
+-def pkg_war(name, ui = "polygerrit", context = [], doc = False, **kwargs):
++def pkg_war(name, ui = "polygerrit", context = [], doc = False, doc_webfont = True, **kwargs):
+     doc_ctx = []
+     doc_lib = []
+     ui_deps = []
+     if ui == "polygerrit":
+         ui_deps.append("//polygerrit-ui/app:polygerrit_ui")
+     if doc:
+-        doc_ctx.append("//Documentation:html")
++        if doc_webfont:
++            doc_ctx.append("//Documentation:html")
++        else:
++            doc_ctx.append("//Documentation:html_webfont_free")
+         doc_lib.append("//Documentation:index")
+ 
+     _pkg_war(

playbooks/zuul/gerrit/run.yaml

@@ -1,5 +1,14 @@
 - hosts: all
   tasks:
+    - name: Patch Gerrit's build system to allow for a release without webfonts
+      shell: |
+        set -ex
+        GERRIT_BASE=/home/zuul/src/gerrit.googlesource.com/gerrit
+        SYSTEM_CONFIG_BASE=/home/zuul/src/opendev.org/opendev/system-config
+        # Patch in the webfont free release target
+        patch -d $GERRIT_BASE -p1 -i \
+          $SYSTEM_CONFIG_BASE/docker/gerrit/patches/webfont_free.patch
+
     - name: Build gerrit
       include_role:
         name: bazelisk-build
@@ -9,7 +18,7 @@
         # polygerrit/javascript plugins into the standard "release"
         # target; we add plugins as separate targets here
         bazelisk_targets:
-          - release
+          - release_webfont_free
           - plugins/zuul-results-summary:zuul-results-summary
 
     # Bazel makes "convenience symlinks" [1] starting with bazel-* to