feat: Use jinja template to render changelog lines, support custom us…

…er templates. (#43)

closes #38

changelog_gen/cli/command.py

@@ -319,7 +319,7 @@ def _gen(  # noqa: PLR0913, C901, PLR0915
     if date_fmt:
         version_string += f" {datetime.now(timezone.utc).strftime(date_fmt)}"
 
-    w = writer.new_writer(context, extension, dry_run=dry_run)
+    w = writer.new_writer(context, extension, dry_run=dry_run, change_template=cfg.change_template)
 
     w.add_version(version_string)
     w.consume(cfg.type_headers, changes)

changelog_gen/config.py

@@ -90,6 +90,7 @@ class Config:
     version_string: str = "v{new_version}"
     footer_parsers: list[str] = dataclasses.field(default_factory=lambda: FOOTER_PARSERS[::])
     link_parsers: list[dict[str, str]] = dataclasses.field(default_factory=list)
+    change_template: str | None = None
 
     # Hooks
     post_process: PostProcessConfig | None = None

changelog_gen/extractor.py

@@ -50,14 +50,6 @@ def issue_ref(self: t.Self) -> str:
                 return footer.value
         return ""
 
-    @property
-    def authors(self: t.Self) -> str:
-        """Extract authors from footers."""
-        for footer in self.footers:
-            if footer.footer == "Authors":
-                return footer.value
-        return ""
-
 
 class ChangeExtractor:
     """Parse commit logs and generate change list."""
@@ -101,7 +93,7 @@ def extract(self: t.Self) -> list[Change]:  # noqa: C901, PLR0912, PLR0915
                 footers = {}
 
                 commit_type = m[1].lower()
-                scope = (m[2] or "").replace("(", "(`").replace(")", "`)")
+                scope = (m[2] or "").replace("(", "").replace(")", "")
                 breaking = m[3] is not None
                 description = m[4].strip()
                 prm = re.search(r"\(#\d+\)$", description)

changelog_gen/writer.py

@@ -8,6 +8,8 @@
 from pathlib import Path
 from tempfile import NamedTemporaryFile
 
+from jinja2 import BaseLoader, Environment
+
 from changelog_gen.util import timer
 
 if t.TYPE_CHECKING:
@@ -34,6 +36,7 @@ def __init__(
         self: t.Self,
         changelog: Path,
         context: Context,
+        change_template: str | None = None,
         *,
         dry_run: bool = False,
     ) -> None:
@@ -45,6 +48,7 @@ def __init__(
             self.existing = lines[self.file_header_line_count + 1 :]
         self.content = []
         self.dry_run = dry_run
+        self._change_template = change_template
 
     @timer
     def add_version(self: t.Self, version: str) -> None:
@@ -74,27 +78,15 @@ def add_section(self: t.Self, header: str, changes: list[Change]) -> None:
         """Add a section to changelog file."""
         self._add_section_header(header)
         for change in sorted(changes):
-            description = f"{change.scope} {change.description}" if change.scope else change.description
-            description = f"{self.bold_string('Breaking:')} {description}" if change.breaking else description
-            description = f"{description} {change.authors}" if change.authors else description
-
-            self._add_section_line(
-                description,
-                change,
-            )
+            self._add_section_line(change)
         self._post_section()
 
-    @timer
-    def bold_string(self: t.Self, string: str) -> str:
-        """Render a string as bold."""
-        return f"**{string.strip()}**"
-
     @timer
     def _add_section_header(self: t.Self, header: str) -> None:
         raise NotImplementedError
 
     @timer
-    def _add_section_line(self: t.Self, description: str, change: Change) -> None:
+    def _add_section_line(self: t.Self, change: Change) -> None:
         raise NotImplementedError
 
     @timer
@@ -132,6 +124,20 @@ class MdWriter(BaseWriter):
     file_header = "# Changelog\n"
     extension = Extension.MD
 
+    @timer
+    def __init__(self: t.Self, *args, **kwargs) -> None:
+        super().__init__(*args, **kwargs)
+        self._change_template = (
+            self._change_template
+            or """
+-{% if change.scope %} (`{{change.scope}}`){% endif %}
+{% if change.breaking %} **Breaking**{% endif %}
+ {{ change.description }}
+{% for footer in change.footers %}{% if footer.footer == "Authors"%} {{footer.value}}{% endif %}{% endfor %}
+{% for link in change.links %} [[{{ link.text }}]({{ link.link }})]{% endfor %}
+"""
+        )
+
     @timer
     def _add_version(self: t.Self, version: str) -> None:
         self.content.extend([f"## {version}", ""])
@@ -141,11 +147,10 @@ def _add_section_header(self: t.Self, header: str) -> None:
         self.content.extend([f"### {header}", ""])
 
     @timer
-    def _add_section_line(self: t.Self, description: str, change: Change) -> None:
-        line = f"- {description}"
+    def _add_section_line(self: t.Self, change: Change) -> None:
+        rtemplate = Environment(loader=BaseLoader()).from_string(self._change_template.replace("\n", ""))  # noqa: S701
 
-        for link in change.links:
-            line = f"{line} [[{link.text}]({link.link})]"
+        line = rtemplate.render(change=change)
 
         self.content.append(line)
 
@@ -164,6 +169,16 @@ class RstWriter(BaseWriter):
     @timer
     def __init__(self: t.Self, *args, **kwargs) -> None:
         super().__init__(*args, **kwargs)
+        self._change_template = (
+            self._change_template
+            or """
+*{% if change.scope %} (`{{change.scope}}`){% endif %}
+{% if change.breaking %} **Breaking**{% endif %}
+ {{ change.description }}
+{% for footer in change.footers %}{% if footer.footer == "Authors"%} {{footer.value}}{% endif %}{% endfor %}
+{% for link in change.links %} [`{{ link.text }}`_]{% endfor %}
+"""
+        )
         self._links = {}
 
     @timer
@@ -185,15 +200,17 @@ def _add_section_header(self: t.Self, header: str) -> None:
         self.content.extend([header, "-" * len(header), ""])
 
     @timer
-    def _add_section_line(self: t.Self, description: str, change: Change) -> None:
-        line = f"* {description}"
+    def _add_section_line(self: t.Self, change: Change) -> None:
+        rtemplate = Environment(loader=BaseLoader()).from_string(self._change_template.replace("\n", ""))  # noqa: S701
+
+        line = rtemplate.render(change=change)
+
+        self.content.extend([line, ""])
 
         for link in change.links:
             line = f"{line} [`{link.text}`_]"
             self._links[link.text] = link.link
 
-        self.content.extend([line, ""])
-
     @timer
     def write(self: t.Self) -> str:
         """Write contents to destination."""
@@ -206,16 +223,17 @@ def write(self: t.Self) -> str:
 def new_writer(
     context: Context,
     extension: Extension,
+    change_template: str | None = None,
     *,
     dry_run: bool = False,
 ) -> BaseWriter:
     """Generate a new writer based on the required extension."""
     changelog = Path(f"CHANGELOG.{extension.value}")
 
     if extension == Extension.MD:
-        return MdWriter(changelog, context, dry_run=dry_run)
+        return MdWriter(changelog, context, dry_run=dry_run, change_template=change_template)
     if extension == Extension.RST:
-        return RstWriter(changelog, context, dry_run=dry_run)
+        return RstWriter(changelog, context, dry_run=dry_run, change_template=change_template)
 
     msg = f'Changelog extension "{extension.value}" not supported.'
     raise ValueError(msg)

docs/configuration.md

@@ -238,6 +238,30 @@ key = "value"
 a_list = ["key", "key2"]
 ```
 
+### `change_template`
+  _**[optional]**_<br />
+  **default**: None
+
+  Customise how changelog entries are formatted, uses
+  [Jinja2](https://jinja.palletsprojects.com/en/3.1.x/) formatting.
+
+  The template will provided with the change object and can render all
+  extracted information as desired. For readability the template can be split
+  over multiple lines, it will be flattened before it is rendered to generate a
+  single line entry.
+
+  Example:
+
+```toml
+[tool.changelog_gen]
+change_template = """
+-{% if change.scope %} (`{{change.scope}}`){% endif %}
+{% if change.breaking %} **Breaking**{% endif %}
+ {{ change.description }}
+{% for footer in change.footers %}{% if footer.footer == "Authors"%} {{footer.value}}{% endif %}{% endfor %}
+{% for link in change.links %} [[{{ link.text }}]({{ link.link }})]{% endfor %}
+"""
+```
 
 ## Versioning
 

pyproject.toml

@@ -41,6 +41,7 @@ rtoml = ">=0.9"
 gitpython = "^3.1.43"
 pygments = "^2.18.0"
 typing_extensions = { version = "^4.7.0", python = "<3.10" }
+jinja2 = "^3.1.4"
 
 [tool.poetry.extras]
 post-process = ["httpx"]