feat(framework) Add FAB hash to load_client_app_fn

src/py/flwr/cli/build.py

@@ -14,26 +14,50 @@
 # ==============================================================================
 """Flower command line interface `build` command."""
 
+import hashlib
 import os
+import shutil
+import tempfile
 import zipfile
 from pathlib import Path
-from typing import Annotated, Optional
+from typing import Annotated, Any, Optional, Union
 
 import pathspec
 import tomli_w
 import typer
 
+from flwr.common.constant import FAB_ALLOWED_EXTENSIONS, FAB_DATE, FAB_HASH_TRUNCATION
+
 from .config_utils import load_and_validate
-from .utils import get_sha256_hash, is_valid_project_name
+from .utils import is_valid_project_name
+
+
+def write_to_zip(
+    zipfile_obj: zipfile.ZipFile, filename: str, contents: Union[bytes, str]
+) -> zipfile.ZipFile:
+    """Set a fixed date and write contents to a zip file."""
+    zip_info = zipfile.ZipInfo(filename)
+    zip_info.date_time = FAB_DATE
+    zipfile_obj.writestr(zip_info, contents)
+    return zipfile_obj
+
 
+def get_fab_filename(conf: dict[str, Any], fab_hash: str) -> str:
+    """Get the FAB filename based on the given config and FAB hash."""
+    publisher = conf["tool"]["flwr"]["app"]["publisher"]
+    name = conf["project"]["name"]
+    version = conf["project"]["version"].replace(".", "-")
+    fab_hash_truncated = fab_hash[:FAB_HASH_TRUNCATION]
+    return f"{publisher}.{name}.{version}.{fab_hash_truncated}.fab"
 
-# pylint: disable=too-many-locals
+
+# pylint: disable=too-many-locals, too-many-statements
 def build(
     app: Annotated[
         Optional[Path],
         typer.Option(help="Path of the Flower App to bundle into a FAB"),
     ] = None,
-) -> str:
+) -> tuple[str, str]:
     """Build a Flower App into a Flower App Bundle (FAB).
 
     You can run ``flwr build`` without any arguments to bundle the app located in the
@@ -85,16 +109,8 @@ def build(
     # Load .gitignore rules if present
     ignore_spec = _load_gitignore(app)
 
-    # Set the name of the zip file
-    fab_filename = (
-        f"{conf['tool']['flwr']['app']['publisher']}"
-        f".{conf['project']['name']}"
-        f".{conf['project']['version'].replace('.', '-')}.fab"
-    )
     list_file_content = ""
 
-    allowed_extensions = {".py", ".toml", ".md"}
-
     # Remove the 'federations' field from 'tool.flwr' if it exists
     if (
         "tool" in conf
@@ -105,38 +121,53 @@ def build(
 
     toml_contents = tomli_w.dumps(conf)
 
-    with zipfile.ZipFile(fab_filename, "w", zipfile.ZIP_DEFLATED) as fab_file:
-        fab_file.writestr("pyproject.toml", toml_contents)
+    with tempfile.NamedTemporaryFile(suffix=".zip", delete=False) as temp_file:
+        temp_filename = temp_file.name
+
+        with zipfile.ZipFile(temp_filename, "w", zipfile.ZIP_DEFLATED) as fab_file:
+            write_to_zip(fab_file, "pyproject.toml", toml_contents)
 
-        # Continue with adding other files
-        for root, _, files in os.walk(app, topdown=True):
-            files = [
+            # Continue with adding other files
+            all_files = [
                 f
-                for f in files
-                if not ignore_spec.match_file(Path(root) / f)
-                and f != fab_filename
-                and Path(f).suffix in allowed_extensions
-                and f != "pyproject.toml"  # Exclude the original pyproject.toml
+                for f in app.rglob("*")
+                if not ignore_spec.match_file(f)
+                and f.name != temp_filename
+                and f.suffix in FAB_ALLOWED_EXTENSIONS
+                and f.name != "pyproject.toml"  # Exclude the original pyproject.toml
             ]
 
-            for file in files:
-                file_path = Path(root) / file
+            for file_path in all_files:
+                # Read the file content manually
+                with open(file_path, "rb") as f:
+                    file_contents = f.read()
+
                 archive_path = file_path.relative_to(app)
-                fab_file.write(file_path, archive_path)
+                write_to_zip(fab_file, str(archive_path), file_contents)
 
                 # Calculate file info
-                sha256_hash = get_sha256_hash(file_path)
+                sha256_hash = hashlib.sha256(file_contents).hexdigest()
                 file_size_bits = os.path.getsize(file_path) * 8  # size in bits
                 list_file_content += f"{archive_path},{sha256_hash},{file_size_bits}\n"
 
-        # Add CONTENT and CONTENT.jwt to the zip file
-        fab_file.writestr(".info/CONTENT", list_file_content)
+            # Add CONTENT and CONTENT.jwt to the zip file
+            write_to_zip(fab_file, ".info/CONTENT", list_file_content)
+
+    # Get hash of FAB file
+    content = Path(temp_filename).read_bytes()
+    fab_hash = hashlib.sha256(content).hexdigest()
+
+    # Set the name of the zip file
+    fab_filename = get_fab_filename(conf, fab_hash)
+
+    # Once the temporary zip file is created, rename it to the final filename
+    shutil.move(temp_filename, fab_filename)
 
     typer.secho(
         f"🎊 Successfully built {fab_filename}", fg=typer.colors.GREEN, bold=True
     )
 
-    return fab_filename
+    return fab_filename, fab_hash
 
 
 def _load_gitignore(app: Path) -> pathspec.PathSpec:

src/py/flwr/cli/install.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 """Flower command line interface `install` command."""
 
-
+import hashlib
 import shutil
 import subprocess
 import tempfile
@@ -25,7 +25,8 @@
 
 import typer
 
-from flwr.common.config import get_flwr_dir
+from flwr.common.config import get_flwr_dir, get_metadata_from_config
+from flwr.common.constant import FAB_HASH_TRUNCATION
 
 from .config_utils import load_and_validate
 from .utils import get_sha256_hash
@@ -91,9 +92,11 @@ def install_from_fab(
     fab_name: Optional[str]
     if isinstance(fab_file, bytes):
         fab_file_archive = BytesIO(fab_file)
+        fab_hash = hashlib.sha256(fab_file).hexdigest()
         fab_name = None
     elif isinstance(fab_file, Path):
         fab_file_archive = fab_file
+        fab_hash = hashlib.sha256(fab_file.read_bytes()).hexdigest()
         fab_name = fab_file.stem
     else:
         raise ValueError("fab_file must be either a Path or bytes")
@@ -126,14 +129,16 @@ def install_from_fab(
             shutil.rmtree(info_dir)
 
             installed_path = validate_and_install(
-                tmpdir_path, fab_name, flwr_dir, skip_prompt
+                tmpdir_path, fab_hash, fab_name, flwr_dir, skip_prompt
             )
 
     return installed_path
 
 
+# pylint: disable=too-many-locals
 def validate_and_install(
     project_dir: Path,
+    fab_hash: str,
     fab_name: Optional[str],
     flwr_dir: Optional[Path],
     skip_prompt: bool = False,
@@ -149,28 +154,17 @@ def validate_and_install(
         )
         raise typer.Exit(code=1)
 
-    publisher = config["tool"]["flwr"]["app"]["publisher"]
-    project_name = config["project"]["name"]
-    version = config["project"]["version"]
+    version, fab_id = get_metadata_from_config(config)
+    publisher, project_name = fab_id.split("/")
+    config_metadata = (publisher, project_name, version, fab_hash)
 
-    if (
-        fab_name
-        and fab_name != f"{publisher}.{project_name}.{version.replace('.', '-')}"
-    ):
-        typer.secho(
-            "❌ FAB file has incorrect name. The file name must follow the format "
-            "`<publisher>.<project_name>.<version>.fab`.",
-            fg=typer.colors.RED,
-            bold=True,
-        )
-        raise typer.Exit(code=1)
+    if fab_name:
+        _validate_fab_and_config_metadata(fab_name, config_metadata)
 
     install_dir: Path = (
         (get_flwr_dir() if not flwr_dir else flwr_dir)
         / "apps"
-        / publisher
-        / project_name
-        / version
+        / f"{publisher}.{project_name}.{version}.{fab_hash[:FAB_HASH_TRUNCATION]}"
     )
     if install_dir.exists():
         if skip_prompt:
@@ -226,3 +220,49 @@ def _verify_hashes(list_content: str, tmpdir: Path) -> bool:
         if not file_path.exists() or get_sha256_hash(file_path) != hash_expected:
             return False
     return True
+
+
+def _validate_fab_and_config_metadata(
+    fab_name: str, config_metadata: tuple[str, str, str, str]
+) -> None:
+    """Validate metadata from the FAB filename and config."""
+    publisher, project_name, version, fab_hash = config_metadata
+
+    fab_name = fab_name.removesuffix(".fab")
+
+    fab_publisher, fab_project_name, fab_version, fab_shorthash = fab_name.split(".")
+    fab_version = fab_version.replace("-", ".")
+
+    # Check FAB filename format
+    if (
+        f"{fab_publisher}.{fab_project_name}.{fab_version}"
+        != f"{publisher}.{project_name}.{version}"
+        or len(fab_shorthash) != FAB_HASH_TRUNCATION  # Verify hash length
+    ):
+        typer.secho(
+            "❌ FAB file has incorrect name. The file name must follow the format "
+            "`<publisher>.<project_name>.<version>.<8hexchars>.fab`.",
+            fg=typer.colors.RED,
+            bold=True,
+        )
+        raise typer.Exit(code=1)
+
+    # Verify hash is a valid hexadecimal
+    try:
+        _ = int(fab_shorthash, 16)
+    except Exception as e:
+        typer.secho(
+            f"❌ FAB file has an invalid hexadecimal string `{fab_shorthash}`.",
+            fg=typer.colors.RED,
+            bold=True,
+        )
+        raise typer.Exit(code=1) from e
+
+    # Verify shorthash matches
+    if fab_shorthash != fab_hash[:FAB_HASH_TRUNCATION]:
+        typer.secho(
+            "❌ The hash in the FAB file name does not match the hash of the FAB.",
+            fg=typer.colors.RED,
+            bold=True,
+        )
+        raise typer.Exit(code=1)

src/py/flwr/cli/run/run.py

@@ -14,7 +14,6 @@
 # ==============================================================================
 """Flower command line interface `run` command."""
 
-import hashlib
 import json
 import subprocess
 import sys
@@ -134,6 +133,7 @@ def run(
         _run_without_superexec(app, federation_config, config_overrides, federation)
 
 
+# pylint: disable=too-many-locals
 def _run_with_superexec(
     app: Path,
     federation_config: dict[str, Any],
@@ -179,9 +179,9 @@ def _run_with_superexec(
     channel.subscribe(on_channel_state_change)
     stub = ExecStub(channel)
 
-    fab_path = Path(build(app))
-    content = fab_path.read_bytes()
-    fab = Fab(hashlib.sha256(content).hexdigest(), content)
+    fab_path, fab_hash = build(app)
+    content = Path(fab_path).read_bytes()
+    fab = Fab(fab_hash, content)
 
     req = StartRunRequest(
         fab=fab_to_proto(fab),
@@ -193,7 +193,7 @@ def _run_with_superexec(
     res = stub.StartRun(req)
 
     # Delete FAB file once it has been sent to the SuperExec
-    fab_path.unlink()
+    Path(fab_path).unlink()
     typer.secho(f"🎊 Successfully started run {res.run_id}", fg=typer.colors.GREEN)
 
     if stream:

src/py/flwr/client/app.py

@@ -202,7 +202,7 @@ def start_client_internal(
     *,
     server_address: str,
     node_config: UserConfig,
-    load_client_app_fn: Optional[Callable[[str, str], ClientApp]] = None,
+    load_client_app_fn: Optional[Callable[[str, str, str], ClientApp]] = None,
     client_fn: Optional[ClientFnExt] = None,
     client: Optional[Client] = None,
     grpc_max_message_length: int = GRPC_MAX_MESSAGE_LENGTH,
@@ -298,7 +298,7 @@ def single_client_factory(
 
             client_fn = single_client_factory
 
-        def _load_client_app(_1: str, _2: str) -> ClientApp:
+        def _load_client_app(_1: str, _2: str, _3: str) -> ClientApp:
             return ClientApp(client_fn=client_fn)
 
         load_client_app_fn = _load_client_app
@@ -529,7 +529,7 @@ def _on_backoff(retry_state: RetryState) -> None:
                         else:
                             # Load ClientApp instance
                             client_app: ClientApp = load_client_app_fn(
-                                fab_id, fab_version
+                                fab_id, fab_version, run.fab_hash
                             )
 
                             # Execute ClientApp

src/py/flwr/client/clientapp/app.py

@@ -132,8 +132,11 @@ def run_clientapp(  # pylint: disable=R0914
             )
 
             try:
-                # Load ClientApp
-                client_app: ClientApp = load_client_app_fn(run.fab_id, run.fab_version)
+                if fab:
+                    # Load ClientApp
+                    client_app: ClientApp = load_client_app_fn(
+                        run.fab_id, run.fab_version, fab.hash_str
+                    )
 
                 # Execute ClientApp
                 reply_message = client_app(message=message, context=context)