From a2ea0b2265f86b1d77eecd5bc8e63f2ff673917c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Budai?= <ondrej@budai.cz>
Date: Fri, 1 Sep 2023 13:06:11 +0200
Subject: [PATCH] stages: add org.osbuild.erofs

Erofs is "a lightweight read-only file system"[1]. Imagine squashfs, but with
faster reads.

This commit adds support for creating it. The new stage is heavily inspired by
the squashfs one. I've decided to add all features of mkfs.erofs that looked
useful: All compression types and most of extended options (excluding the
compatibility ones, we can always add them later).

[1]: https://en.wikipedia.org/wiki/EROFS
---
 stages/org.osbuild.erofs | 101 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100755 stages/org.osbuild.erofs

diff --git a/stages/org.osbuild.erofs b/stages/org.osbuild.erofs
new file mode 100755
index 00000000..f74dabdc
--- /dev/null
+++ b/stages/org.osbuild.erofs
@@ -0,0 +1,101 @@
+#!/usr/bin/python3
+"""
+Create a file containing an erofs filesystem named `filename`.
+
+See https://en.wikipedia.org/wiki/EROFS for details about the
+filesystem.
+
+Buildhost commands used: `mkfs.erofs`
+"""
+
+import os
+import subprocess
+import sys
+
+import osbuild.api
+
+SCHEMA_2 = """
+"options": {
+  "additionalProperties": false,
+  "required": ["filename"],
+  "properties": {
+    "filename": {
+      "description": "Filename for the output",
+      "type": "string"
+    },
+    "compression": {
+      "type": "object",
+      "additionalProperties": false,
+      "required": ["method"],
+      "properties": {
+        "method": {
+          "description": "Compression method",
+          "enum": ["lz4", "lz4hc", "lzma"]
+        },
+        "level": {
+          "description": "Compression level. Note that different methods support different levels. See mkfs.erofs(1) for more details",
+          "type": "number"
+        }
+      }
+    },
+    "options": {
+      "description": "Extended options for the filesystem, see mkfs.erofs(1)",
+      "type": "array",
+      "minItems": 1,
+      "items:": {
+        "enum": [
+          "all-fragments",
+          "dedupe",
+          "force-inode-compact",
+          "force-inode-extended",
+          "force-inode-blockmap",
+          "force-chunk-indexes",
+          "fragments",
+          "noinline_data",
+          "ztailpacking"
+        ]
+      }
+    }
+  }
+},
+"inputs": {
+  "type": "object",
+  "additionalProperties": false,
+  "required": ["tree"],
+  "properties": {
+    "tree": {
+      "type": "object",
+      "additionalProperties": true
+    }
+  }
+}
+"""
+
+
+def main(inputs, output_dir, options):
+    source = inputs["tree"]["path"]
+    filename = options["filename"].lstrip("/")
+    compression = options.get("compression")
+
+    target = os.path.join(output_dir, filename)
+
+    cmd = ["mkfs.erofs", target, source]
+
+    if compression:
+        method = compression["method"]
+        if compression.get("level"):
+            method += f",{compression['level']}"
+        cmd += ["-z", method]
+
+    if options:
+        cmd += ["-E", ",".join(options)]
+
+    subprocess.run(cmd, check=True)
+
+    return 0
+
+
+if __name__ == '__main__':
+    args = osbuild.api.arguments()
+    r = main(args["inputs"], args["tree"], args["options"])
+    sys.exit(r)