test: avoid recompiling examples for every agent

We compile the UFFD and seccomp example programs as a session fixture.
If we run the tests in parallel, there is one session per worker and we
end up downloading and compiling the examples for each worker (worst
case).

Instead, use the same approach as the Firecracker and jailer binaries.

Signed-off-by: Pablo Barbáchano <[email protected]>

Author: pb8o

tests/conftest.py

@@ -24,7 +24,6 @@
 
 import inspect
 import os
-import platform
 import re
 import shutil
 import sys
@@ -196,8 +195,8 @@ def change_net_config_space_bin(test_fc_session_root_path):
     yield change_net_config_space_bin
 
 
-@pytest.fixture(scope="session")
-def bin_seccomp_paths(test_fc_session_root_path):
+@pytest.fixture
+def bin_seccomp_paths():
     """Build jailers and jailed binaries to test seccomp.
 
     They currently consist of:
@@ -206,48 +205,20 @@ def bin_seccomp_paths(test_fc_session_root_path):
     * a jailed binary that follows the seccomp rules;
     * a jailed binary that breaks the seccomp rules.
     """
-    seccomp_build_path = (
-        Path(test_fc_session_root_path) / build_tools.CARGO_RELEASE_REL_PATH
-    )
-    release_binaries_path = seccomp_build_path / build_tools.RELEASE_BINARIES_REL_PATH
-
-    seccomp_examples = ["jailer", "harmless", "malicious", "panic"]
-
-    demos = {}
-
-    for example in seccomp_examples:
-        build_tools.cargo_build(
-            seccomp_build_path,
-            f"--release --target {platform.machine()}-unknown-linux-musl --example seccomp_{example}",
-        )
-
-        demos[f"demo_{example}"] = release_binaries_path / f"examples/seccomp_{example}"
-
+    demos = {
+        f"demo_{example}": build_tools.get_example(f"seccomp_{example}")
+        for example in ["jailer", "harmless", "malicious", "panic"]
+    }
     yield demos
 
 
-@pytest.fixture(scope="session")
-def uffd_handler_paths(test_fc_session_root_path):
+@pytest.fixture
+def uffd_handler_paths():
     """Build UFFD handler binaries."""
-    uffd_build_path = (
-        Path(test_fc_session_root_path) / build_tools.CARGO_RELEASE_REL_PATH
-    )
-    release_binaries_path = uffd_build_path / build_tools.RELEASE_BINARIES_REL_PATH
-
-    uffd_handlers = ["malicious", "valid"]
-
-    handlers = {}
-
-    for handler in uffd_handlers:
-        build_tools.cargo_build(
-            uffd_build_path,
-            f"--release --target {platform.machine()}-unknown-linux-musl --example uffd_{handler}_handler",
-        )
-
-        handlers[f"{handler}_handler"] = (
-            release_binaries_path / f"examples/uffd_{handler}_handler"
-        )
-
+    handlers = {
+        f"{handler}_handler": build_tools.get_example(f"uffd_{handler}_handler")
+        for handler in ["malicious", "valid"]
+    }
     yield handlers
 
 

tests/host_tools/cargo_build.py

@@ -66,16 +66,20 @@ def cargo_test(path, extra_args=""):
 
 
 @with_filelock
-def get_binary(name, *, workspace_dir=FC_WORKSPACE_DIR):
+def get_binary(name, *, workspace_dir=FC_WORKSPACE_DIR, example=False):
     """Build a binary"""
     target = DEFAULT_BUILD_TARGET
     target_dir = workspace_dir / "build" / "cargo_target"
     bin_path = target_dir / target / "release" / name
+    cmd = f"-p {name}"
+    if example:
+        bin_path = target_dir / target / "release" / "examples" / name
+        cmd = f"--example {name}"
     if not bin_path.exists():
         env = {"RUSTFLAGS": get_rustflags()}
         cargo(
             "build",
-            f"-p {name} --release --target {target}",
+            f"--release --target {target} {cmd}",
             env=env,
             cwd=workspace_dir,
         )
@@ -95,6 +99,11 @@ def get_firecracker_binaries(*, workspace_dir=FC_WORKSPACE_DIR):
     )
 
 
+def get_example(name, *args, **kwargs):
+    """Build an example binary"""
+    return get_binary(name, *args, **kwargs, example=True)
+
+
 @with_filelock
 def run_seccompiler_bin(bpf_path, json_path=defs.SECCOMP_JSON_DIR, basic=False):
     """