stages/erofs: Add exclude_paths support

Add the ability to exclude files and directories from the erofs
image. This uses the mkfs.erofs --exclude-regex feature, so simple
matches or regexes can be used.

stages/org.osbuild.erofs

@@ -10,6 +10,7 @@ def main(inputs, output_dir, options):
     source = inputs["tree"]["path"]
     filename = options["filename"].lstrip("/")
     compression = options.get("compression")
+    exclude_paths = options.get("exclude_paths")
 
     target = os.path.join(output_dir, filename)
 
@@ -29,6 +30,10 @@ def main(inputs, output_dir, options):
     if cluster_size:
         cmd += ["-C", f"{cluster_size}"]
 
+    if exclude_paths:
+        for e in exclude_paths:
+            cmd += ["--exclude-regex", e]
+
     subprocess.run(cmd, check=True)
 
     return 0

stages/org.osbuild.erofs.meta.json

@@ -16,6 +16,13 @@
           "description": "Filename for the output",
           "type": "string"
         },
+        "exclude_paths": {
+          "type": "array",
+          "description": "Regex of paths to exclude, can be files or directories",
+          "items": {
+            "type": "string"
+          }
+        },
         "compression": {
           "type": "object",
           "additionalProperties": false,

stages/test/test_erofs.py

@@ -16,6 +16,7 @@ TEST_INPUT = [
     ({"options": ["dedupe"]}, ["-E", "dedupe"]),
     ({"options": ["all-fragments", "force-inode-compact"]}, ["-E", "all-fragments,force-inode-compact"]),
     ({"cluster-size": 131072, "options": ["dedupe"]}, ["-E", "dedupe", "-C", "131072"]),
+    ({"exclude_paths": ["boot/", "root/"]}, ["--exclude-regex", "boot/", "--exclude-regex", "root/"])
 ]