feat(core): brotli-compress .socket.facts.json on full-scan upload

Compress the reachability facts file to a `.socket.facts.json.br` multipart
part before uploading it as part of a full scan. The Socket API transparently
decompresses parts named exactly `.socket.facts.json.br` and stores plain JSON,
so the stored result is unchanged while the on-the-wire payload shrinks by
roughly 10-40x for typical facts files.

This keeps large tier-1 reachability facts files under the API's per-file
upload size cap. Previously an oversized facts file made the full-scan upload
fail (surfaced as an HTTP 4xx/502 with the scan stuck and no report produced).

- Compress at the upload boundary (Core.create_full_scan); the on-disk file is
  left untouched so local consumers still read plain .socket.facts.json.
- Only files whose basename is exactly .socket.facts.json are compressed (the
  API matches that exact name); a custom --reach-output-file name and empty
  placeholder files are left as plain uploads.
- Never blocks an upload: any compression failure falls back to the plain file.
- Add brotli (CPython) / brotlicffi (PyPy) dependency.

Author: mtorp

CHANGELOG.md

@@ -1,5 +1,31 @@
 # Changelog
 
+## 2.3.1
+
+### New: brotli-compressed `.socket.facts.json` upload
+
+The reachability facts file (`.socket.facts.json`) is now brotli-compressed before it is
+uploaded as part of a full scan. The Socket API transparently decompresses any multipart
+part named exactly `.socket.facts.json.br` and stores it as plain `.socket.facts.json`, so
+the stored result is unchanged — but the on-the-wire payload shrinks dramatically (a
+~262 MB facts file compresses to roughly 15–30 MB).
+
+This fixes large tier‑1 reachability scans that previously failed when the uncompressed
+facts file exceeded the API's per‑file upload size cap (surfaced to the CLI as an HTTP
+4xx/“502”, leaving the scan stuck with no report).
+
+Details:
+
+- Compression happens at the upload boundary (`Core.create_full_scan`); the file on disk is
+  left untouched, so local consumers (SARIF/JSON output, tier‑1 finalize, alert selection)
+  continue to read the plain `.socket.facts.json`.
+- Only a file whose basename is exactly `.socket.facts.json` is compressed (the API matches
+  that exact name). A custom `--reach-output-file` name is uploaded uncompressed, as before.
+- Empty baseline-scan placeholder files are not compressed.
+- Compression never blocks an upload: if it fails for any reason it falls back to uploading
+  the plain file.
+- Adds a `brotli` (CPython) / `brotlicffi` (PyPy) dependency.
+
 ## 2.3.0
 
 ### New: `--exit-code-on-api-error`

pyproject.toml

@@ -6,7 +6,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "socketsecurity"
-version = "2.3.0"
+version = "2.3.1"
 requires-python = ">= 3.11"
 license = {"file" = "LICENSE"}
 dependencies = [
@@ -19,6 +19,8 @@ dependencies = [
     "socketdev>=3.0.33,<4.0.0",
     "bs4>=0.0.2",
     "markdown>=3.10",
+    "brotli>=1.0.9; platform_python_implementation == 'CPython'",
+    "brotlicffi>=1.0.9; platform_python_implementation != 'CPython'",
 ]
 readme = "README.md"
 description = "Socket Security CLI for CI/CD"

socketsecurity/__init__.py

@@ -1,3 +1,3 @@
 __author__ = 'socket.dev'
-__version__ = '2.3.0'
+__version__ = '2.3.1'
 USER_AGENT = f'SocketPythonCLI/{__version__}'

socketsecurity/core/__init__.py

@@ -51,6 +51,24 @@
 
 _HUMANIZE_BOUNDARY = re.compile(r"(?<=[a-z0-9])(?=[A-Z])|(?<=[A-Z])(?=[A-Z][a-z])")
 
+# Reachability facts-file upload compression.
+#
+# The Socket full-scan endpoint transparently brotli-decompresses any multipart part
+# whose basename is exactly ``.socket.facts.json.br`` and stores it as plain
+# ``.socket.facts.json``. Compressing the facts file on upload keeps it well under the
+# server's per-file size cap (a ~262 MB facts file compresses to roughly 15-30 MB),
+# which is required for large reachability (tier 1) scans to succeed.
+#
+# The server matches the *exact* name ``.socket.facts.json.br``, so we only compress
+# files whose basename is exactly ``.socket.facts.json`` (a custom ``--reach-output-file``
+# name would not be decompressed server-side, so it is left as a plain upload).
+SOCKET_FACTS_FILENAME = ".socket.facts.json"
+SOCKET_FACTS_BROTLI_FILENAME = ".socket.facts.json.br"
+# Brotli quality (0-11); 5 is a good speed/ratio tradeoff for large JSON payloads.
+SOCKET_FACTS_BROTLI_QUALITY = 5
+# Largest brotli window (2**24 bytes); improves the ratio on large facts files.
+SOCKET_FACTS_BROTLI_LGWIN = 24
+
 
 def _humanize_alert_type(alert_type: str) -> str:
     """Convert a camelCase/PascalCase alert type into a Title-Cased label.
@@ -544,6 +562,91 @@ def finalize_tier1_scan(self, full_scan_id: str, facts_file_path: str) -> bool:
             log.debug(f"Unable to finalize tier 1 scan: {e}")
             return False
 
+    @staticmethod
+    def _compress_facts_file(source_path: str) -> str:
+        """Brotli-compress a ``.socket.facts.json`` file to a sibling ``.socket.facts.json.br``.
+
+        The source is streamed in chunks so a large facts file (hundreds of MB) never has
+        to be held in memory at once. The compressed file is written next to the source so
+        that the multipart key the SDK derives keeps the same directory prefix, only with a
+        ``.br`` basename.
+
+        Args:
+            source_path: Path to the plain ``.socket.facts.json`` file.
+
+        Returns:
+            Path to the compressed sibling file.
+        """
+        # Imported lazily so the dependency is only needed when actually uploading a facts
+        # file. brotlicffi is the API-compatible fallback used on PyPy / non-CPython runtimes.
+        try:
+            import brotli
+        except ImportError:
+            import brotlicffi as brotli
+
+        target_path = os.path.join(os.path.dirname(source_path), SOCKET_FACTS_BROTLI_FILENAME)
+        compressor = brotli.Compressor(
+            quality=SOCKET_FACTS_BROTLI_QUALITY,
+            lgwin=SOCKET_FACTS_BROTLI_LGWIN,
+        )
+        chunk_size = 1024 * 1024  # 1 MiB
+        with open(source_path, "rb") as src, open(target_path, "wb") as dst:
+            while True:
+                chunk = src.read(chunk_size)
+                if not chunk:
+                    break
+                compressed = compressor.process(chunk)
+                if compressed:
+                    dst.write(compressed)
+            dst.write(compressor.finish())
+        return target_path
+
+    def _compress_facts_files_for_upload(self, files: List[str]) -> Tuple[List[str], List[str]]:
+        """Replace any ``.socket.facts.json`` upload entry with a brotli-compressed ``.br`` sibling.
+
+        The Socket full-scan endpoint transparently decompresses a multipart part named
+        exactly ``.socket.facts.json.br``, so compressing here keeps a large facts file under
+        the server's per-file size cap without changing the stored result. Files whose
+        basename is not exactly ``.socket.facts.json`` are left untouched (the server only
+        matches that exact name), as are empty placeholder files (e.g. baseline scans).
+
+        Compression never blocks an upload: if it fails for any reason (missing optional
+        ``brotli`` dependency, unwritable directory, etc.) the original plain file is used.
+
+        Args:
+            files: The list of file paths about to be uploaded.
+
+        Returns:
+            ``(upload_files, temp_paths)`` where ``upload_files`` is the possibly-rewritten
+            list to upload and ``temp_paths`` are compressed files the caller must delete
+            once the upload completes.
+        """
+        upload_files: List[str] = []
+        temp_paths: List[str] = []
+        for file_path in files:
+            try:
+                if (
+                    os.path.basename(file_path) == SOCKET_FACTS_FILENAME
+                    and os.path.isfile(file_path)
+                    and os.path.getsize(file_path) > 0
+                ):
+                    compressed_path = self._compress_facts_file(file_path)
+                    log.debug(
+                        f"Brotli-compressed {file_path} for upload: "
+                        f"{os.path.getsize(file_path)} -> {os.path.getsize(compressed_path)} bytes "
+                        f"(uploading as {SOCKET_FACTS_BROTLI_FILENAME})"
+                    )
+                    upload_files.append(compressed_path)
+                    temp_paths.append(compressed_path)
+                    continue
+            except Exception as e:
+                # Never let compression break an upload: fall back to the plain file.
+                log.warning(
+                    f"Failed to brotli-compress facts file {file_path}, uploading uncompressed: {e}"
+                )
+            upload_files.append(file_path)
+        return upload_files, temp_paths
+
     def create_full_scan(self, files: List[str], params: FullScanParams, base_paths: Optional[List[str]] = None) -> FullScan:
         """
         Creates a new full scan via the Socket API.
@@ -559,7 +662,19 @@ def create_full_scan(self, files: List[str], params: FullScanParams, base_paths:
         log.info("Creating new full scan")
         create_full_start = time.time()
 
-        res = self.sdk.fullscans.post(files, params, use_types=True, use_lazy_loading=True, max_open_files=50, base_paths=base_paths)
+        # Brotli-compress the reachability facts file (if present) so it is uploaded as a
+        # `.socket.facts.json.br` part. The API decompresses it server-side, keeping a large
+        # facts file under the per-file upload size cap. See _compress_facts_files_for_upload.
+        upload_files, compressed_temp_files = self._compress_facts_files_for_upload(files)
+        try:
+            res = self.sdk.fullscans.post(upload_files, params, use_types=True, use_lazy_loading=True, max_open_files=50, base_paths=base_paths)
+        finally:
+            for temp_file in compressed_temp_files:
+                try:
+                    os.unlink(temp_file)
+                    log.debug(f"Cleaned up temporary compressed facts file: {temp_file}")
+                except OSError as cleanup_error:
+                    log.debug(f"Failed to clean up temporary compressed facts file {temp_file}: {cleanup_error}")
         if not res.success:
             log.error(f"Error creating full scan: {res.message}, status: {res.status}")
             raise Exception(f"Error creating full scan: {res.message}, status: {res.status}")

tests/core/test_facts_compression.py

@@ -0,0 +1,111 @@
+"""Tests for brotli compression of the reachability facts file on upload.
+
+The Socket full-scan endpoint transparently decompresses a multipart part named exactly
+`.socket.facts.json.br`, so the CLI compresses the facts file before uploading it. These
+tests cover the helpers in `Core` that do that rewriting.
+"""
+import json
+import os
+
+try:
+    import brotli
+except ImportError:  # pragma: no cover - PyPy / non-CPython fallback
+    import brotlicffi as brotli
+
+from socketsecurity.core import (
+    SOCKET_FACTS_BROTLI_FILENAME,
+    SOCKET_FACTS_FILENAME,
+    Core,
+)
+
+
+def _write(path, data: bytes):
+    with open(path, "wb") as f:
+        f.write(data)
+    return path
+
+
+def test_compress_facts_file_roundtrips(tmp_path):
+    """The compressed sibling decompresses back to the exact original bytes."""
+    source = tmp_path / SOCKET_FACTS_FILENAME
+    payload = json.dumps({"components": [{"id": str(i)} for i in range(1000)]}).encode()
+    _write(str(source), payload)
+
+    compressed_path = Core._compress_facts_file(str(source))
+
+    # Compressed file is a sibling named exactly `.socket.facts.json.br`.
+    assert compressed_path == str(tmp_path / SOCKET_FACTS_BROTLI_FILENAME)
+    assert os.path.basename(compressed_path) == SOCKET_FACTS_BROTLI_FILENAME
+    # The original is untouched (other code paths still read it locally).
+    assert source.read_bytes() == payload
+    # Roundtrip matches.
+    with open(compressed_path, "rb") as f:
+        assert brotli.decompress(f.read()) == payload
+
+
+def test_compress_for_upload_rewrites_facts_entry(tmp_path):
+    """A `.socket.facts.json` entry is replaced by its `.br` sibling; others pass through."""
+    core = Core.__new__(Core)
+    facts = _write(str(tmp_path / SOCKET_FACTS_FILENAME), b'{"a": 1}')
+    manifest = _write(str(tmp_path / "package.json"), b"{}")
+
+    upload_files, temp_paths = core._compress_facts_files_for_upload([facts, manifest])
+
+    expected_br = str(tmp_path / SOCKET_FACTS_BROTLI_FILENAME)
+    assert upload_files == [expected_br, manifest]
+    assert temp_paths == [expected_br]
+    assert os.path.isfile(expected_br)
+    # Non-facts files are never compressed.
+    assert manifest in upload_files
+
+
+def test_compress_for_upload_preserves_directory_prefix(tmp_path):
+    """The `.br` sibling keeps the facts file's directory so the relative key is preserved."""
+    core = Core.__new__(Core)
+    subdir = tmp_path / "nested"
+    subdir.mkdir()
+    facts = _write(str(subdir / SOCKET_FACTS_FILENAME), b'{"a": 1}')
+
+    upload_files, temp_paths = core._compress_facts_files_for_upload([facts])
+
+    assert upload_files == [str(subdir / SOCKET_FACTS_BROTLI_FILENAME)]
+    assert temp_paths == [str(subdir / SOCKET_FACTS_BROTLI_FILENAME)]
+
+
+def test_empty_facts_file_is_not_compressed(tmp_path):
+    """Empty placeholder facts files (e.g. baseline scans) are uploaded as-is."""
+    core = Core.__new__(Core)
+    empty_facts = _write(str(tmp_path / SOCKET_FACTS_FILENAME), b"")
+
+    upload_files, temp_paths = core._compress_facts_files_for_upload([empty_facts])
+
+    assert upload_files == [empty_facts]
+    assert temp_paths == []
+    assert not (tmp_path / SOCKET_FACTS_BROTLI_FILENAME).exists()
+
+
+def test_custom_named_facts_file_is_not_compressed(tmp_path):
+    """A custom --reach-output-file name is not compressed (server only matches the exact name)."""
+    core = Core.__new__(Core)
+    custom = _write(str(tmp_path / "custom.facts.json"), b'{"a": 1}')
+
+    upload_files, temp_paths = core._compress_facts_files_for_upload([custom])
+
+    assert upload_files == [custom]
+    assert temp_paths == []
+
+
+def test_compression_failure_falls_back_to_plain_file(tmp_path, monkeypatch):
+    """If compression raises, the original plain file is uploaded instead of failing."""
+    core = Core.__new__(Core)
+    facts = _write(str(tmp_path / SOCKET_FACTS_FILENAME), b'{"a": 1}')
+
+    def boom(_source_path):
+        raise RuntimeError("brotli unavailable")
+
+    monkeypatch.setattr(Core, "_compress_facts_file", staticmethod(boom))
+
+    upload_files, temp_paths = core._compress_facts_files_for_upload([facts])
+
+    assert upload_files == [facts]
+    assert temp_paths == []