felipecrv commented on code in PR #39009:
URL: https://github.com/apache/arrow/pull/39009#discussion_r1414721290
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cpp/src/arrow/filesystem/azurefs.cc:
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@@ -815,6 +815,233 @@ class AzureFileSystem::Impl {
}
}
+ private:
+ template <typename OnContainer>
+ Status ListContainers(const Azure::Core::Context& context,
+ OnContainer&& on_container) const {
+ Azure::Storage::Blobs::ListBlobContainersOptions options;
+ // Deleted containers are not returned.
+ options.Include =
Azure::Storage::Blobs::Models::ListBlobContainersIncludeFlags::None;
+ try {
+ auto container_list_response =
+ blob_service_client_->ListBlobContainers(options, context);
+ for (; container_list_response.HasPage();
+ container_list_response.MoveToNextPage(context)) {
+ for (const auto& container : container_list_response.BlobContainers) {
+ RETURN_NOT_OK(on_container(container));
+ }
+ }
+ } catch (const Azure::Storage::StorageException& exception) {
+ return internal::ExceptionToStatus("Failed to list account containers.",
exception);
+ }
+ return Status::OK();
+ }
+
+ static FileInfo FileInfoFromBlob(const std::string& container,
+ const
Azure::Storage::Blobs::Models::BlobItem& blob) {
+ if (blob.Name.back() == internal::kSep) {
+ return DirectoryFileInfoFromPath(container + internal::kSep + blob.Name);
+ }
+ std::string path;
+ path.reserve(container.size() + 1 + blob.Name.size());
+ path += container;
+ path += internal::kSep;
+ path += blob.Name;
+ FileInfo info{std::move(path), FileType::File};
+ info.set_size(blob.BlobSize);
+
info.set_mtime(std::chrono::system_clock::time_point{blob.Details.LastModified});
+ return info;
+ }
+
+ static FileInfo DirectoryFileInfoFromPath(const std::string& path) {
+ return FileInfo{std::string{internal::RemoveTrailingSlash(path)},
+ FileType::Directory};
+ }
+
+ static std::string_view BasenameView(std::string_view s) {
+ auto offset = s.find_last_of(internal::kSep);
+ auto tail = (offset == std::string_view::npos) ? s : s.substr(offset);
+ return internal::RemoveTrailingSlash(tail, /*preserve_root=*/false);
+ }
+
+ /// \brief List the blobs at the root of a container or some dir in a
container.
+ ///
+ /// \pre container_client is the client for the container named like the
first
+ /// segment of select.base_dir.
+ Status GetFileInfoWithSelectorFromContainer(
+ const Azure::Storage::Blobs::BlobContainerClient& container_client,
+ const Azure::Core::Context& context, Azure::Nullable<int32_t>
page_size_hint,
+ const FileSelector& select, FileInfoVector* acc_results) {
+ ARROW_ASSIGN_OR_RAISE(auto base_location,
AzureLocation::FromString(select.base_dir));
+
+ bool found = false;
+ Azure::Storage::Blobs::ListBlobsOptions options;
+ if (internal::GetAbstractPathDepth(base_location.path) == 0) {
+ // If the base_dir is the root of the container, then we want to list
all blobs in
+ // the container and the Prefix should be empty and not even include the
trailing
+ // slash because the container itself represents the `<container>/`
directory.
+ options.Prefix = {};
+ found = true; // Unless the container itself is not found later!
+ } else {
+ options.Prefix = internal::EnsureTrailingSlash(base_location.path);
+ }
+ options.PageSizeHint = page_size_hint;
+ options.Include =
Azure::Storage::Blobs::Models::ListBlobsIncludeFlags::Metadata;
+
+ // When Prefix.Value() contains a trailing slash and we find a blob that
+ // matches it completely, it is an empty directory marker blob for the
+ // directory we're listing from, and we should skip it.
+ auto is_empty_dir_marker =
+ [&options](const Azure::Storage::Blobs::Models::BlobItem& blob)
noexcept -> bool {
+ return options.Prefix.HasValue() && blob.Name == options.Prefix.Value();
+ };
+
+ auto recurse = [&](const std::string& blob_prefix) noexcept -> Status {
+ if (select.recursive && select.max_recursion > 0) {
+ FileSelector sub_select;
+ sub_select.base_dir = base_location.container;
+ sub_select.base_dir += internal::kSep;
+ sub_select.base_dir += internal::RemoveTrailingSlash(blob_prefix);
+ sub_select.allow_not_found = true;
+ sub_select.recursive = true;
+ sub_select.max_recursion = select.max_recursion - 1;
+ return GetFileInfoWithSelectorFromContainer(
+ container_client, context, page_size_hint, sub_select,
acc_results);
+ }
+ return Status::OK();
+ };
+
+ // (*acc_results)[*last_dir_reported] is the last FileType::Directory in
the results
+ // produced through this loop over the response pages.
+ std::optional<size_t> last_dir_reported{};
+ auto matches_last_dir_reported = [&last_dir_reported,
+ acc_results](const FileInfo& info)
noexcept {
+ if (!last_dir_reported.has_value() || info.type() !=
FileType::Directory) {
+ return false;
+ }
+ const auto& last_dir = (*acc_results)[*last_dir_reported];
+ return BasenameView(info.path()) == BasenameView(last_dir.path());
+ };
+
+ auto process_blob =
+ [&](const Azure::Storage::Blobs::Models::BlobItem& blob) noexcept {
+ if (!is_empty_dir_marker(blob)) {
+ const auto& info = acc_results->emplace_back(
+ FileInfoFromBlob(base_location.container, blob));
+ if (info.type() == FileType::Directory) {
+ last_dir_reported = acc_results->size() - 1;
+ }
+ }
+ };
+ auto process_prefix = [&](const std::string& prefix) noexcept -> Status {
+ const std::string path = base_location.container + internal::kSep +
prefix;
+ const auto& info =
acc_results->emplace_back(DirectoryFileInfoFromPath(path));
+ if (ARROW_PREDICT_FALSE(matches_last_dir_reported(info))) {
+ acc_results->pop_back();
+ } else {
+ last_dir_reported = acc_results->size() - 1;
+ return recurse(prefix);
+ }
+ return Status::OK();
+ };
+
+ try {
+ auto list_response =
+ container_client.ListBlobsByHierarchy(/*delimiter=*/"/", options,
context);
+ for (; list_response.HasPage(); list_response.MoveToNextPage(context)) {
+ if (list_response.Blobs.empty() && list_response.BlobPrefixes.empty())
{
+ continue;
+ }
+ found = true;
+ // Blob and BlobPrefixes are sorted by name, so we can merge-iterate
+ // them to ensure returned results are all sorted.
+ size_t blob_index = 0;
+ size_t blob_prefix_index = 0;
+ while (blob_index < list_response.Blobs.size() &&
+ blob_prefix_index < list_response.BlobPrefixes.size()) {
+ const auto& blob = list_response.Blobs[blob_index];
+ const auto& prefix = list_response.BlobPrefixes[blob_prefix_index];
+ const int cmp = blob.Name.compare(prefix);
+ if (cmp < 0) {
+ process_blob(blob);
+ blob_index += 1;
+ } else if (cmp > 0) {
+ RETURN_NOT_OK(process_prefix(prefix));
+ blob_prefix_index += 1;
+ } else { // there is a blob (empty dir marker) and a prefix with
the same name
+ DCHECK_EQ(blob.Name, prefix);
+ RETURN_NOT_OK(process_prefix(prefix));
+ blob_index += 1;
+ blob_prefix_index += 1;
+ }
+ }
+ for (; blob_index < list_response.Blobs.size(); blob_index++) {
+ process_blob(list_response.Blobs[blob_index]);
+ }
+ for (; blob_prefix_index < list_response.BlobPrefixes.size();
+ blob_prefix_index++) {
+
RETURN_NOT_OK(process_prefix(list_response.BlobPrefixes[blob_prefix_index]));
+ }
+ }
+ } catch (const Azure::Storage::StorageException& exception) {
+ if (exception.ErrorCode == "ContainerNotFound") {
+ found = false;
+ } else {
+ return internal::ExceptionToStatus(
+ "Failed to list blobs in a directory: " + select.base_dir + ": " +
+ container_client.GetUrl(),
+ exception);
+ }
+ }
+
+ return found || select.allow_not_found
+ ? Status::OK()
+ : ::arrow::fs::internal::PathNotFound(select.base_dir);
+ }
+
+ public:
+ Status GetFileInfoWithSelector(const Azure::Core::Context& context,
+ Azure::Nullable<int32_t> page_size_hint,
+ const FileSelector& select,
+ FileInfoVector* acc_results) {
+ ARROW_ASSIGN_OR_RAISE(auto base_location,
AzureLocation::FromString(select.base_dir));
+
+ if (base_location.container.empty()) {
+ // Without a container, the base_location is equivalent to the filesystem
+ // root -- `/`. FileSelector::allow_not_found doesn't matter in this case
+ // because the root always exists.
+ auto on_container =
+ [&](const Azure::Storage::Blobs::Models::BlobContainerItem&
container) {
+ // Deleted containers are not listed by ListContainers.
+ DCHECK(!container.IsDeleted);
+
+ // Every container is considered a directory.
+ FileInfo info{container.Name, FileType::Directory};
+ info.set_mtime(
+
std::chrono::system_clock::time_point{container.Details.LastModified});
+ acc_results->push_back(std::move(info));
+
+ // Recurse into containers (subdirectories) if requested.
+ if (select.recursive && select.max_recursion > 0) {
+ FileSelector sub_select;
+ sub_select.base_dir = container.Name;
+ sub_select.allow_not_found = true;
+ sub_select.recursive = true;
+ sub_select.max_recursion = select.max_recursion - 1;
+ ARROW_RETURN_NOT_OK(GetFileInfoWithSelector(context,
page_size_hint,
+ sub_select,
acc_results));
+ }
+ return Status::OK();
+ };
+ return ListContainers(context, std::move(on_container));
Review Comment:
`page_size_hint` only applies to the pagination of blobs. If I were to pass
page size here, it would be a separate constant, but I thought this would be an
overkill.
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