Add jupyterlite_ignore_contents config, mapping to --ignore-contents arg in JupyterLite build (#309)

* Add `jupyterlite_ignore_contents` config, mapping to `--ignore-contents` arg to JupyterLite build

* Add documentation for new config

* Add appropriate prefix to print call

* Format 🔔

Author: mfisher87

docs/configuration.md

@@ -12,6 +12,19 @@ jupyterlite_contents = ["./path/to/my/notebooks/", "my_other_notebook.ipynb"]
 
 `jupyterlite_contents` can be a string or a list of strings. Each string is expanded using the Python `glob.glob` function with its recursive option. See the [glob documentation](https://docs.python.org/3/library/glob.html#glob.glob) and the [wildcard pattern documentation](https://docs.python.org/3/library/fnmatch.html#fnmatch.fnmatch) for more details. This option supports both paths relative to the docs source directory and absolute ones.
 
+### Ignoring content
+
+You can exclude some contents from your specified contents, for example:
+
+```python
+jupyterlite_contents = ["./path/to/my/contents"]
+jupyterlite_ignore_contents = [r".*\.txt"]
+```
+
+`jupyterlite_ignore_contents` can be a string or a list of strings. Strings are used as Python regular expressions to match and exclude files from your custom content. It's best to use raw string literals for your ignore strings, otherwise you'll need to double-escape (in other words, `r".*\.txt"` is more readable than `".*\\.txt"`).
+
+Each string is passed directly to [the JupyterLite build `--ignore-contents` CLI argument](https://jupyterlite.readthedocs.io/en/stable/reference/cli.html#common-parameters).
+
 ## JupyterLite dir
 
 By default, jupyterlite-sphinx runs the `jupyter lite build` command in the docs directory, you can overwrite this behavior and ask jupyterlite to build in a given directory:

jupyterlite_sphinx/jupyterlite_sphinx.py

@@ -947,6 +947,22 @@ def inited(app: Sphinx, config):
         app.add_source_suffix(".ipynb", "jupyterlite_notebook")
 
 
+def jupyterlite_ignore_contents_args(ignore_contents):
+    """Generate `--ignore-contents` argument for each pattern.
+
+    NOTE: Unlike generating `--contents` args, we _do not_ expand globs to generate the
+    arguments. We just hand the config off to the JupyterLite build.
+    """
+    if ignore_contents is None:
+        ignore_contents = []
+    elif isinstance(ignore_contents, str):
+        ignore_contents = [ignore_contents]
+
+    return [
+        arg for pattern in ignore_contents for arg in ["--ignore-contents", pattern]
+    ]
+
+
 def jupyterlite_build(app: Sphinx, error):
     if error is not None:
         # Do not build JupyterLite
@@ -1014,6 +1030,10 @@ def jupyterlite_build(app: Sphinx, error):
 
                 contents.extend(["--contents", contents_path])
 
+        ignore_contents = jupyterlite_ignore_contents_args(
+            app.env.config.jupyterlite_ignore_contents,
+        )
+
         apps_option = []
         for liteapp in ["notebooks", "edit", "lab", "repl", "tree", "consoles"]:
             apps_option.extend(["--apps", liteapp])
@@ -1032,6 +1052,7 @@ def jupyterlite_build(app: Sphinx, error):
             *contents,
             "--contents",
             os.path.join(app.srcdir, CONTENT_DIR),
+            *ignore_contents,
             "--output-dir",
             os.path.join(app.outdir, JUPYTERLITE_DIR),
             *apps_option,
@@ -1064,6 +1085,7 @@ def jupyterlite_build(app: Sphinx, error):
             kwargs["stdout"] = subprocess.PIPE
             kwargs["stderr"] = subprocess.PIPE
 
+        print(f"[jupyterlite-sphinx] Command: {command}")
         completed_process: CompletedProcess[bytes] = subprocess.run(
             command, cwd=app.srcdir, check=True, **kwargs
         )
@@ -1108,6 +1130,7 @@ def setup(app):
     app.add_config_value("jupyterlite_overrides", None, rebuild="html")
     app.add_config_value("jupyterlite_dir", str(app.srcdir), rebuild="html")
     app.add_config_value("jupyterlite_contents", None, rebuild="html")
+    app.add_config_value("jupyterlite_ignore_contents", None, rebuild="html")
     app.add_config_value("jupyterlite_bind_ipynb_suffix", True, rebuild="html")
     app.add_config_value("jupyterlite_silence", True, rebuild=True)
     app.add_config_value("strip_tagged_cells", False, rebuild=True)