templates: support Jinja include

Support Jinja include directive:

    {% include 'distro/common/foo' %}

Paths are relative to project root.

apkg/pkgtemplate.py

@@ -48,6 +48,11 @@ class PackageTemplate:
         self.style = style
         self.selection = selection
         self.distro_rules = None
+        self.setup_env()
+
+    def setup_env(self):
+        self.env = jinja2.Environment(
+            loader=jinja2.FileSystemLoader('.'))
 
     @property
     def path(self):
@@ -142,9 +147,7 @@ class PackageTemplate:
                 # TODO: filtering should be exposed through config
                 if render_filter(src):
                     log.verbose("rendering file: %s -> %s", src, dst)
-                    t = None
-                    with src.open('r') as srcf:
-                        t = jinja2.Template(srcf.read())
+                    t = self.env.get_template(str(src))
                     with dst.open('w') as dstf:
                         dstf.write(t.render(**tvars) + '\n')
                 else:
@@ -160,8 +163,7 @@ class PackageTemplate:
         """
         src = self.path / name
         tvars = self.template_vars(tvars=tvars)
-        with src.open('r') as srcf:
-            t = jinja2.Template(srcf.read())
+        t = self.env.get_template(str(src))
         return t.render(**tvars) + '\n'
 
     def __repr__(self):

docs/templates.md

@@ -35,6 +35,9 @@ You can use all [jinja] templating features with following variables provided by
 * `now`: current date and time in changelog format (provided only by pkgstyles
   with changelog dates such as `deb` and `rpm`)
 
+[include] tag is also supported and can be used to include
+files relative to project root.
+
 Example Debian `changelog`:
 
 ```jinja
@@ -182,5 +185,6 @@ Examples:
 
 
 [jinja]: https://jinja.palletsprojects.com/en/3.0.x/templates/
+[include]: https://jinja.palletsprojects.com/en/3.0.x/templates/#include
 [distro in templates]: distro.md#distro-in-templates
 [target distro]: distro.md#target-distro

examples/templates/distro/common/shared.txt

+Included from shared.txt file. Name: {{ name }}

examples/templates/distro/pkg/deb/changelog

@@ -2,6 +2,7 @@ apkg-example-templates ({{ version }}-{{ release }}~{{ distro.tiny }}) unstable;
 
   * new upstream version {{ version }}
   * distro: {{ distro }} / {{ distro.idver }} / {{ distro.tiny }}
+  * {% include 'distro/common/shared.txt' %}
 {%- if distro.match('debian >= 11', 'ubuntu > 20.04') %}
   * new Debian-based
 {%- elif distro.match('deb-old') %}

examples/templates/distro/pkg/rpm/apkg-example-templates.spec

@@ -21,6 +21,7 @@ This is a minimal example of apkg templating features.
 * {{ now }} Jakub Ružička <jakub.ruzicka@nic.cz> - {{ version }}-{{ release }}
 - new upstream version {{ version }}
 - distro: {{ distro }} / {{ distro.idver }} / {{ distro.tiny }}
+- {% include 'distro/common/shared.txt' %}
 {%- if distro.match('fedora') %}
 - Fedora-specific block
 {%- elif distro.match('centos <= 7', 'rhel <= 7') %}

tests/self/test_templates.py

@@ -53,7 +53,8 @@ def test_template_select(proj, distro, name, style):
 
 RE_RPM_CH = r"""\* \w{3} \w{3} \d{2} \d{4} [^-]+- ([^-]+)-(\w+)
 - new upstream version (\S+)
-- distro: ([^\n]+)\n?(.*)\Z"""
+- distro: ([^\n]+)
+- Included from shared.txt file. Name: apkg-example-templates\n?(.*)\Z"""
 
 
 @pytest.mark.parametrize('distro,extra', [
@@ -88,7 +89,8 @@ def test_template_render_rpm(proj, capsys, distro, extra):
 
 RE_DEB_CH = r"""apkg-example-templates \(([^-]+)-([^)]+)\) unstable; .*
   \* new upstream version (\S+)
-  \* distro: ([^\n]+)\n?(.*)
+  \* distro: ([^\n]+)
+  \* Included from shared.txt file. Name: apkg-example-templates\n?(.*)
  -- .+?  \w{3}, \d+ \w{3} \d{4} [\d:]{8} [+-]?\d{4}"""