CI(test_runner): Upload all test artifacts if preserve_database_files is enabled (#7990)

## Problem

There's a `NeonEnvBuilder#preserve_database_files` parameter that allows
you to keep database files for debugging purposes (by default, files get
cleaned up), but there's no way to get these files from a CI run.
This PR adds handling of `NeonEnvBuilder#preserve_database_files` and
adds the compressed test output directory to Allure reports (for tests
with this parameter enabled).

Ref https://github.com/neondatabase/neon/issues/6967

## Summary of changes
- Compress and add the whole test output directory to Allure reports
- Currently works only with `neon_env_builder` fixture
- Remove `preserve_database_files = True` from sharding tests as
unneeded

---------

Co-authored-by: Christian Schwarz <christian@neon.tech>

test_runner/README.md

@@ -81,7 +81,7 @@ should go.
 Useful parameters and commands:
 
 `--preserve-database-files` to preserve pageserver (layer) and safekeer (segment) timeline files on disk
-after running a test suite. Such files might be large, so removed by default; but might be useful for debugging or creation of svg images with layer file contents.
+after running a test suite. Such files might be large, so removed by default; but might be useful for debugging or creation of svg images with layer file contents. If `NeonEnvBuilder#preserve_database_files` set to `True` for a particular test, the whole `repo` directory will be attached to Allure report (thus uploaded to S3) as `everything.tar.zst` for this test.
 
 Let stdout, stderr and `INFO` log messages go to the terminal instead of capturing them:
 `./scripts/pytest -s --log-cli-level=INFO ...`

test_runner/fixtures/neon_fixtures.py

@@ -1394,7 +1394,7 @@ def _shared_simple_env(
         pg_distrib_dir=pg_distrib_dir,
         pg_version=pg_version,
         run_id=run_id,
-        preserve_database_files=pytestconfig.getoption("--preserve-database-files"),
+        preserve_database_files=cast(bool, pytestconfig.getoption("--preserve-database-files")),
         test_name=request.node.name,
         test_output_dir=test_output_dir,
         pageserver_virtual_file_io_engine=pageserver_virtual_file_io_engine,
@@ -1469,7 +1469,7 @@ def neon_env_builder(
         pg_version=pg_version,
         broker=default_broker,
         run_id=run_id,
-        preserve_database_files=pytestconfig.getoption("--preserve-database-files"),
+        preserve_database_files=cast(bool, pytestconfig.getoption("--preserve-database-files")),
         pageserver_virtual_file_io_engine=pageserver_virtual_file_io_engine,
         test_name=request.node.name,
         test_output_dir=test_output_dir,
@@ -1478,6 +1478,11 @@ def neon_env_builder(
         pageserver_default_tenant_config_compaction_algorithm=pageserver_default_tenant_config_compaction_algorithm,
     ) as builder:
         yield builder
+        # Propogate `preserve_database_files` to make it possible to use in other fixtures,
+        # like `test_output_dir` fixture for attaching all database files to Allure report.
+        request.node.user_properties.append(
+            ("preserve_database_files", builder.preserve_database_files)
+        )
 
 
 @dataclass
@@ -4478,7 +4483,16 @@ def test_output_dir(
 
     yield test_dir
 
-    allure_attach_from_dir(test_dir)
+    preserve_database_files = False
+    for k, v in request.node.user_properties:
+        # NB: the neon_env_builder fixture uses this fixture (test_output_dir).
+        # So, neon_env_builder's cleanup runs before here.
+        # The cleanup propagates NeonEnvBuilder.preserve_database_files into this user property.
+        if k == "preserve_database_files":
+            assert isinstance(v, bool)
+            preserve_database_files = v
+
+    allure_attach_from_dir(test_dir, preserve_database_files)
 
 
 class FileAndThreadLock:

test_runner/fixtures/utils.py

@@ -240,9 +240,18 @@ ATTACHMENT_NAME_REGEX: re.Pattern = re.compile(  # type: ignore[type-arg]
 )
 
 
-def allure_attach_from_dir(dir: Path):
+def allure_attach_from_dir(dir: Path, preserve_database_files: bool = False):
     """Attach all non-empty files from `dir` that matches `ATTACHMENT_NAME_REGEX` to Allure report"""
 
+    if preserve_database_files:
+        zst_file = dir.with_suffix(".tar.zst")
+        with zst_file.open("wb") as zst:
+            cctx = zstandard.ZstdCompressor()
+            with cctx.stream_writer(zst) as compressor:
+                with tarfile.open(fileobj=compressor, mode="w") as tar:
+                    tar.add(dir, arcname="")
+        allure.attach.file(zst_file, "everything.tar.zst", "application/zstd", "tar.zst")
+
     for attachment in Path(dir).glob("**/*"):
         if ATTACHMENT_NAME_REGEX.fullmatch(attachment.name) and attachment.stat().st_size > 0:
             name = str(attachment.relative_to(dir))

test_runner/regress/test_sharding.py

@@ -48,8 +48,6 @@ def test_sharding_smoke(
     # that the scrubber doesn't barf when it sees a sharded tenant.
     neon_env_builder.enable_pageserver_remote_storage(s3_storage())
 
-    neon_env_builder.preserve_database_files = True
-
     env = neon_env_builder.init_start(
         initial_tenant_shard_count=shard_count, initial_tenant_shard_stripe_size=stripe_size
     )
@@ -372,8 +370,6 @@ def test_sharding_split_smoke(
     # that the scrubber doesn't barf when it sees a sharded tenant.
     neon_env_builder.enable_pageserver_remote_storage(s3_storage())
 
-    neon_env_builder.preserve_database_files = True
-
     non_default_tenant_config = {"gc_horizon": 77 * 1024 * 1024}
 
     env = neon_env_builder.init_configs(True)