add support for feeding user configuration

Signed-off-by: Igor Gnatenko <ignatenkobrain@fedoraproject.org>

README.md

@@ -0,0 +1,26 @@
+# rust2rpm
+
+Convert Rust crates to RPM.
+
+## `.rust2rpm.conf`
+
+You can place configuration file which is used as source for additional
+information for spec generation.
+
+Some simple example would be better than many words ;)
+
+```ini
+[DEFAULT]
+buildrequires =
+  pkgconfig(foo) >= 1.2.3
+lib.requires =
+  pkgconfig(foo) >= 1.2.3
+
+[fedora]
+bin.requires =
+  findutils
+buildrequires =
+lib.requires =
+lib+default.requires =
+  pkgconfig(bar) >= 2.0.0
+```

README.rst

@@ -1,5 +0,0 @@
-========
-rust2rpm
-========
-
-Convert Rust crates to RPM.

rust2rpm/__main__.py

@@ -199,6 +199,11 @@ def make_diff_metadata(crate, version, patch=False, store=False):
         shutil.copy2(cratef, os.path.join(os.getcwd(), f"{metadata.name}-{version}.crate"))
     return crate, diff, metadata
 
+def to_list(s):
+    if not s:
+        return []
+    return list(filter(None, (l.strip() for l in s.splitlines())))
+
 def main():
     parser = argparse.ArgumentParser("rust2rpm",
                                      formatter_class=argparse.RawTextHelpFormatter)
@@ -232,6 +237,7 @@ def main():
                                                store=args.store_crate)
 
     JINJA_ENV.globals["normalize_deps"] = normalize_deps
+    JINJA_ENV.globals["to_list"] = to_list
     template = JINJA_ENV.get_template("main.spec")
 
     if args.patch and len(diff) > 0:
@@ -287,6 +293,13 @@ def main():
         kwargs["license"] = license
         kwargs["license_comments"] = comments
 
+    conf = configparser.ConfigParser(interpolation=configparser.ExtendedInterpolation())
+    conf.read(".rust2rpm.conf")
+    if args.target not in conf:
+        conf.add_section(args.target)
+
+    kwargs["distconf"] = conf[args.target]
+
     spec_file = f"rust-{metadata.name}.spec"
     spec_contents = template.render(md=metadata, patch_file=patch_file, **kwargs)
     if args.stdout:

rust2rpm/templates/main.spec

@@ -65,6 +65,9 @@ BuildRequires:  {{ req }}
   {% endfor %}
 %endif
 {% endif %}
+{% for req in to_list(distconf.get("buildrequires"))|sort %}
+BuildRequires:  {{ req }}
+{% endfor %}
 
 %global _description \
 {% if md.description is none %}
@@ -81,6 +84,9 @@ Summary:        %{summary}
   {% if rust_group is defined %}
 Group:          # FIXME
   {% endif %}
+  {% for req in to_list(distconf.get("bin.requires"))|sort %}
+Requires:       {{ req }}
+  {% endfor %}
 
 %description -n %{crate}
 %{summary}.
@@ -106,7 +112,13 @@ Group:          # FIXME
   {% do features.insert(0, None) %}
   {% do features.insert(1, "default") %}
   {% for feature in features %}
-    {% set pkg = "-n %%{name}+%s-devel"|format(feature) if feature is not none else "   devel" %}
+    {% if feature is none %}
+      {% set pkg = "   devel" %}
+      {% set conf_prefix = "lib" %}
+    {% else %}
+      {% set pkg = "-n %%{name}+%s-devel"|format(feature) %}
+      {% set conf_prefix = "lib+%s"|format(feature) %}
+    {% endif %}
 %package     {{ pkg }}
 Summary:        %{summary}
     {% if rust_group is defined %}
@@ -122,6 +134,9 @@ Requires:       cargo
 Requires:       {{ req }}
       {% endfor %}
     {% endif %}
+    {% for req in to_list(distconf.get("%s.requires"|format(conf_prefix)))|sort %}
+Requires:       {{ req }}
+    {% endfor %}
 
 %description {{ pkg }} %{_description}