Add script for uploading debug symbols to sentry

Author: edolstra

maintainers/upload-debug-info-to-sentry.py

@@ -0,0 +1,140 @@
+#!/usr/bin/env python3
+
+import argparse
+import json
+import os
+import re
+import subprocess
+import sys
+import urllib.error
+import urllib.parse
+import urllib.request
+
+NAR_DIR = "/tmp/nars"
+DEBUG_INFO_DIR = "/tmp/debug-info"
+
+
+def get_dynamic_libraries(executable: str) -> list[str]:
+    result = subprocess.run(["ldd", executable], capture_output=True, text=True, check=True)
+    libs = []
+    for line in result.stdout.splitlines():
+        # ldd output lines look like:
+        #   libfoo.so.1 => /nix/store/.../libfoo.so.1 (0x...)
+        #   /lib64/ld-linux-x86-64.so.2 (0x...)
+        m = re.search(r"=> (/\S+)", line)
+        if m:
+            libs.append(m.group(1))
+        elif line.strip().startswith("/"):
+            path = line.strip().split()[0]
+            libs.append(path)
+    return libs
+
+
+def get_build_id(path: str) -> str | None:
+    result = subprocess.run(["readelf", "-n", path], capture_output=True, text=True)
+    m = re.search(r"Build ID:\s+([0-9a-f]+)", result.stdout)
+    return m.group(1) if m else None
+
+
+def download_nar(build_id: str, archive: str) -> str:
+    """Download a NAR to /tmp/nars and return the local path. Skips if already present."""
+    base_url = f"https://cache.nixos.org/debuginfo/{build_id}"
+    nar_url = urllib.parse.urljoin(base_url, archive)
+    filename = nar_url.split("/")[-1]
+    local_path = os.path.join(NAR_DIR, filename)
+    if not os.path.exists(local_path):
+        os.makedirs(NAR_DIR, exist_ok=True)
+        print(f"    downloading {nar_url} ...", file=sys.stderr)
+        urllib.request.urlretrieve(nar_url, local_path)
+    else:
+        print(f"    already have {filename}", file=sys.stderr)
+    return local_path
+
+
+def extract_debug_symbols(nar_path: str, member: str, build_id: str) -> str:
+    """Extract a member from a .nar.xz into /tmp/debug-info/<build_id>.debug. Returns the output path."""
+    out_path = os.path.join(DEBUG_INFO_DIR, f"{build_id}.debug")
+    if os.path.exists(out_path):
+        print(f"    already extracted {out_path}", file=sys.stderr)
+        return out_path
+    os.makedirs(DEBUG_INFO_DIR, exist_ok=True)
+    print(f"    extracting {member} -> {out_path} ...", file=sys.stderr)
+    xz = subprocess.Popen(["xz", "-d"], stdin=open(nar_path, "rb"), stdout=subprocess.PIPE)
+    nar_cat = subprocess.run(
+        ["nix", "nar", "cat", "/dev/stdin", member],
+        stdin=xz.stdout,
+        capture_output=True,
+        check=True,
+    )
+    xz.wait()
+    with open(out_path, "wb") as f:
+        f.write(nar_cat.stdout)
+    return out_path
+
+
+def find_debug_file_in_dirs(build_id: str, debug_dirs: list[str]) -> str | None:
+    """Look for a .debug file by build ID under <dir>/lib/debug/.build-id/NN/NNN.debug."""
+    subpath = os.path.join("lib", "debug", ".build-id", build_id[:2], build_id[2:] + ".debug")
+    for d in debug_dirs:
+        candidate = os.path.join(d, subpath)
+        if os.path.exists(candidate):
+            return candidate
+    return None
+
+
+def fetch_debuginfo(build_id: str) -> dict | None:
+    url = f"https://cache.nixos.org/debuginfo/{build_id}"
+    try:
+        with urllib.request.urlopen(url) as resp:
+            return json.loads(resp.read())
+    except urllib.error.HTTPError as e:
+        if e.code == 404:
+            return None
+        raise
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Upload ELF debug symbols to Sentry."
+    )
+    parser.add_argument("executable", help="Path to the ELF executable (e.g. ./result/bin/nix)")
+    parser.add_argument("--project", required=True, help="Sentry project ID")
+    parser.add_argument("--debug-dir", action="append", default=[], metavar="DIR",
+                        help="Directory to search for debug files (may be repeated)")
+    args = parser.parse_args()
+
+    debug_files = []
+
+    libs = [args.executable] + get_dynamic_libraries(args.executable)
+    print("ELF files to process:", file=sys.stderr)
+    for lib in libs:
+        build_id = get_build_id(lib)
+        if build_id is None:
+            print(f"  {lib} (no build ID)", file=sys.stderr)
+            continue
+
+        local = find_debug_file_in_dirs(build_id, args.debug_dir)
+        if local:
+            print(f"  {lib} ({build_id}): found locally at {local}", file=sys.stderr)
+            debug_files.append(local)
+            continue
+
+        debuginfo = fetch_debuginfo(build_id)
+        if debuginfo is None:
+            print(f"  {lib} ({build_id}, no debug info in cache)", file=sys.stderr)
+            continue
+        print(f"  {lib} ({build_id}): member={debuginfo['member']}", file=sys.stderr)
+        nar_path = download_nar(build_id, debuginfo["archive"])
+        debug_file = extract_debug_symbols(nar_path, debuginfo["member"], build_id)
+        debug_files.append(debug_file)
+
+    if debug_files:
+        print(f"Uploading {len(debug_files)} debug file(s) to Sentry...", file=sys.stderr)
+        subprocess.run(
+            ["sentry-cli", "debug-files", "upload", "--project", args.project] + debug_files,
+            check=True,
+        )
+
+
+if __name__ == "__main__":
+    main()