ClickHouse/src/Storages/StorageURL.cpp

#include <Storages/StorageURL.h>

#include <Interpreters/Context.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Parsers/ASTCreateQuery.h>
#include <Parsers/ASTLiteral.h>

#include <IO/ReadHelpers.h>
#include <IO/WriteBufferFromHTTP.h>
#include <IO/WriteHelpers.h>
#include <IO/ConnectionTimeouts.h>
#include <IO/ConnectionTimeoutsContext.h>

#include <Formats/FormatFactory.h>
#include <Processors/Formats/IOutputFormat.h>
#include <Processors/Formats/IInputFormat.h>

#include <Processors/Transforms/AddingDefaultsTransform.h>

#include <Poco/Net/HTTPRequest.h>
#include <Processors/Sources/SourceWithProgress.h>
#include <QueryPipeline/QueryPipelineBuilder.h>
#include <Processors/Executors/PullingPipelineExecutor.h>
#include <base/logger_useful.h>
#include <algorithm>


namespace DB
{
namespace ErrorCodes
{
    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
    extern const int NETWORK_ERROR;
    extern const int BAD_ARGUMENTS;
}


IStorageURLBase::IStorageURLBase(
    const Poco::URI & uri_,
    ContextPtr /*context_*/,
    const StorageID & table_id_,
    const String & format_name_,
    const std::optional<FormatSettings> & format_settings_,
    const ColumnsDescription & columns_,
    const ConstraintsDescription & constraints_,
    const String & comment,
    const String & compression_method_,
    const ReadWriteBufferFromHTTP::HTTPHeaderEntries & headers_)
    : IStorage(table_id_), uri(uri_), compression_method(compression_method_), format_name(format_name_), format_settings(format_settings_), headers(headers_)
{
    StorageInMemoryMetadata storage_metadata;
    storage_metadata.setColumns(columns_);
    storage_metadata.setConstraints(constraints_);
    storage_metadata.setComment(comment);
    setInMemoryMetadata(storage_metadata);
}

namespace
{
    ReadWriteBufferFromHTTP::HTTPHeaderEntries getHeaders(
        const ReadWriteBufferFromHTTP::HTTPHeaderEntries & headers_)
    {
        ReadWriteBufferFromHTTP::HTTPHeaderEntries headers(headers_.begin(), headers_.end());
        // Propagate OpenTelemetry trace context, if any, downstream.
        if (CurrentThread::isInitialized())
        {
            const auto & thread_trace_context = CurrentThread::get().thread_trace_context;
            if (thread_trace_context.trace_id != UUID())
            {
                headers.emplace_back("traceparent",
                    thread_trace_context.composeTraceparentHeader());

                if (!thread_trace_context.tracestate.empty())
                {
                    headers.emplace_back("tracestate",
                        thread_trace_context.tracestate);
                }
            }
        }
        return headers;
    }

    class StorageURLSource : public SourceWithProgress
    {
    using URIParams = std::vector<std::pair<String, String>>;

    public:
        StorageURLSource(
            const std::vector<Poco::URI> & uri_options,
            const std::string & method,
            std::function<void(std::ostream &)> callback,
            const String & format,
            const std::optional<FormatSettings> & format_settings,
            String name_,
            const Block & sample_block,
            ContextPtr context,
            const ColumnsDescription & columns,
            UInt64 max_block_size,
            const ConnectionTimeouts & timeouts,
            const String & compression_method,
            const ReadWriteBufferFromHTTP::HTTPHeaderEntries & headers_ = {},
            const URIParams & params = {})
            : SourceWithProgress(sample_block), name(std::move(name_))
        {
            auto headers = getHeaders(headers_);
            /// Lazy initialization. We should not perform requests in constructor, because we need to do it in query pipeline.
            initialize = [=, this]
            {
                WriteBufferFromOwnString error_message;
                for (auto option = uri_options.begin(); option < uri_options.end(); ++option)
                {
                    auto request_uri = *option;
                    for (const auto & [param, value] : params)
                        request_uri.addQueryParameter(param, value);

                    try
                    {
                        read_buf = wrapReadBufferWithCompressionMethod(
                            std::make_unique<ReadWriteBufferFromHTTP>(
                                request_uri,
                                method,
                                callback,
                                timeouts,
                                context->getSettingsRef().max_http_get_redirects,
                                credentials,
                                DBMS_DEFAULT_BUFFER_SIZE,
                                context->getReadSettings(),
                                headers,
                                context->getRemoteHostFilter()),
                            chooseCompressionMethod(request_uri.getPath(), compression_method));
                    }
                    catch (...)
                    {
                        if (uri_options.size() == 1)
                            throw;

                        if (option == uri_options.end() - 1)
                            throw Exception(ErrorCodes::NETWORK_ERROR, "All uri options are unreachable. {}", error_message.str());

                        error_message << option->toString() << " error: " << getCurrentExceptionMessage(false) << "\n";
                        tryLogCurrentException(__PRETTY_FUNCTION__);
                    }
                }

                auto input_format = FormatFactory::instance().getInput(format, *read_buf, sample_block, context, max_block_size, format_settings);
                QueryPipelineBuilder builder;
                builder.init(Pipe(input_format));

                builder.addSimpleTransform([&](const Block & cur_header)
                {
                    return std::make_shared<AddingDefaultsTransform>(cur_header, columns, *input_format, context);
                });

                pipeline = std::make_unique<QueryPipeline>(QueryPipelineBuilder::getPipeline(std::move(builder)));
                reader = std::make_unique<PullingPipelineExecutor>(*pipeline);
            };
        }

        String getName() const override
        {
            return name;
        }

        Chunk generate() override
        {
            if (initialize)
            {
                initialize();
                initialize = {};
            }

            if (!reader)
                return {};

            Chunk chunk;
            if (reader->pull(chunk))
                return chunk;

            pipeline->reset();
            reader.reset();

            return {};
        }

    private:
        std::function<void()> initialize;

        String name;
        std::unique_ptr<ReadBuffer> read_buf;
        std::unique_ptr<QueryPipeline> pipeline;
        std::unique_ptr<PullingPipelineExecutor> reader;

        Poco::Net::HTTPBasicCredentials credentials{};
    };
}

StorageURLSink::StorageURLSink(
    const Poco::URI & uri,
    const String & format,
    const std::optional<FormatSettings> & format_settings,
    const Block & sample_block,
    ContextPtr context,
    const ConnectionTimeouts & timeouts,
    const CompressionMethod compression_method)
    : SinkToStorage(sample_block)
{
    write_buf = wrapWriteBufferWithCompressionMethod(
            std::make_unique<WriteBufferFromHTTP>(uri, Poco::Net::HTTPRequest::HTTP_POST, timeouts),
            compression_method, 3);
    writer = FormatFactory::instance().getOutputFormat(format, *write_buf, sample_block,
        context, {} /* write callback */, format_settings);
}


void StorageURLSink::consume(Chunk chunk)
{
    if (is_first_chunk)
    {
        writer->doWritePrefix();
        is_first_chunk = false;
    }

    writer->write(getHeader().cloneWithColumns(chunk.detachColumns()));
}

void StorageURLSink::onFinish()
{
    writer->doWriteSuffix();
    writer->flush();
    write_buf->finalize();
}


std::string IStorageURLBase::getReadMethod() const
{
    return Poco::Net::HTTPRequest::HTTP_GET;
}

std::vector<std::pair<std::string, std::string>> IStorageURLBase::getReadURIParams(
    const Names & /*column_names*/,
    const StorageMetadataPtr & /*metadata_snapshot*/,
    const SelectQueryInfo & /*query_info*/,
    ContextPtr /*context*/,
    QueryProcessingStage::Enum & /*processed_stage*/,
    size_t /*max_block_size*/) const
{
    return {};
}

std::function<void(std::ostream &)> IStorageURLBase::getReadPOSTDataCallback(
    const Names & /*column_names*/,
    const StorageMetadataPtr & /*metadata_snapshot*/,
    const SelectQueryInfo & /*query_info*/,
    ContextPtr /*context*/,
    QueryProcessingStage::Enum & /*processed_stage*/,
    size_t /*max_block_size*/) const
{
    return nullptr;
}


Pipe IStorageURLBase::read(
    const Names & column_names,
    const StorageMetadataPtr & metadata_snapshot,
    SelectQueryInfo & query_info,
    ContextPtr local_context,
    QueryProcessingStage::Enum processed_stage,
    size_t max_block_size,
    unsigned /*num_streams*/)
{
    auto params = getReadURIParams(column_names, metadata_snapshot, query_info, local_context, processed_stage, max_block_size);
    std::vector<Poco::URI> uri_options{uri};
    return Pipe(std::make_shared<StorageURLSource>(
        uri_options,
        getReadMethod(),
        getReadPOSTDataCallback(
            column_names, metadata_snapshot, query_info,
            local_context, processed_stage, max_block_size),
        format_name,
        format_settings,
        getName(),
        getHeaderBlock(column_names, metadata_snapshot),
        local_context,
        metadata_snapshot->getColumns(),
        max_block_size,
        ConnectionTimeouts::getHTTPTimeouts(local_context),
        compression_method, headers, params));
}


Pipe StorageURLWithFailover::read(
    const Names & column_names,
    const StorageMetadataPtr & metadata_snapshot,
    SelectQueryInfo & query_info,
    ContextPtr local_context,
    QueryProcessingStage::Enum processed_stage,
    size_t max_block_size,
    unsigned /*num_streams*/)
{
    auto params = getReadURIParams(column_names, metadata_snapshot, query_info, local_context, processed_stage, max_block_size);
    auto pipe =  Pipe(std::make_shared<StorageURLSource>(
        uri_options,
        getReadMethod(),
        getReadPOSTDataCallback(
            column_names, metadata_snapshot, query_info,
            local_context, processed_stage, max_block_size),
        format_name,
        format_settings,
        getName(),
        getHeaderBlock(column_names, metadata_snapshot),
        local_context,
        metadata_snapshot->getColumns(),
        max_block_size,
        ConnectionTimeouts::getHTTPTimeouts(local_context),
        compression_method, headers, params));
    std::shuffle(uri_options.begin(), uri_options.end(), thread_local_rng);
    return pipe;
}


SinkToStoragePtr IStorageURLBase::write(const ASTPtr & /*query*/, const StorageMetadataPtr & metadata_snapshot, ContextPtr context)
{
    return std::make_shared<StorageURLSink>(uri, format_name,
        format_settings, metadata_snapshot->getSampleBlock(), context,
        ConnectionTimeouts::getHTTPTimeouts(context),
        chooseCompressionMethod(uri.toString(), compression_method));
}

StorageURL::StorageURL(
    const Poco::URI & uri_,
    const StorageID & table_id_,
    const String & format_name_,
    const std::optional<FormatSettings> & format_settings_,
    const ColumnsDescription & columns_,
    const ConstraintsDescription & constraints_,
    const String & comment,
    ContextPtr context_,
    const String & compression_method_,
    const ReadWriteBufferFromHTTP::HTTPHeaderEntries & headers_)
    : IStorageURLBase(uri_, context_, table_id_, format_name_, format_settings_, columns_, constraints_, comment, compression_method_, headers_)
{
    context_->getRemoteHostFilter().checkURL(uri);
}


StorageURLWithFailover::StorageURLWithFailover(
    const std::vector<String> & uri_options_,
    const StorageID & table_id_,
    const String & format_name_,
    const std::optional<FormatSettings> & format_settings_,
    const ColumnsDescription & columns_,
    const ConstraintsDescription & constraints_,
    ContextPtr context_,
    const String & compression_method_)
    : StorageURL(Poco::URI(), table_id_, format_name_, format_settings_, columns_, constraints_, String{}, context_, compression_method_)
{
    for (const auto & uri_option : uri_options_)
    {
        Poco::URI poco_uri(uri_option);
        context_->getRemoteHostFilter().checkURL(poco_uri);
        uri_options.emplace_back(std::move(poco_uri));
        LOG_DEBUG(&Poco::Logger::get("StorageURLDistributed"), "Adding URL option: {}", uri_option);
    }
}


FormatSettings StorageURL::getFormatSettingsFromArgs(const StorageFactory::Arguments & args)
{
    // Use format settings from global server context + settings from
    // the SETTINGS clause of the create query. Settings from current
    // session and user are ignored.
    FormatSettings format_settings;
    if (args.storage_def->settings)
    {
        FormatFactorySettings user_format_settings;

        // Apply changed settings from global context, but ignore the
        // unknown ones, because we only have the format settings here.
        const auto & changes = args.getContext()->getSettingsRef().changes();
        for (const auto & change : changes)
        {
            if (user_format_settings.has(change.name))
            {
                user_format_settings.set(change.name, change.value);
            }
        }

        // Apply changes from SETTINGS clause, with validation.
        user_format_settings.applyChanges(args.storage_def->settings->changes);

        format_settings = getFormatSettings(args.getContext(),
            user_format_settings);
    }
    else
    {
        format_settings = getFormatSettings(args.getContext());
    }

    return format_settings;
}

URLBasedDataSourceConfiguration StorageURL::getConfiguration(ASTs & args, ContextPtr local_context)
{
    URLBasedDataSourceConfiguration configuration;

    if (auto named_collection = getURLBasedDataSourceConfiguration(args, local_context))
    {
        auto [common_configuration, storage_specific_args] = named_collection.value();
        configuration.set(common_configuration);

        if (!storage_specific_args.empty())
        {
            String illegal_args;
            for (const auto & arg : storage_specific_args)
            {
                if (!illegal_args.empty())
                    illegal_args += ", ";
                illegal_args += arg.first;
            }
            throw Exception(ErrorCodes::BAD_ARGUMENTS, "Unknown arguments {} for table function URL", illegal_args);
        }
    }
    else
    {
        if (args.size() != 2 && args.size() != 3)
            throw Exception(
                "Storage URL requires 2 or 3 arguments: url, name of used format and optional compression method.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);

        for (auto & arg : args)
            arg = evaluateConstantExpressionOrIdentifierAsLiteral(arg, local_context);

        configuration.url = args[0]->as<ASTLiteral &>().value.safeGet<String>();
        configuration.format = args[1]->as<ASTLiteral &>().value.safeGet<String>();
        if (args.size() == 3)
            configuration.compression_method = args[2]->as<ASTLiteral &>().value.safeGet<String>();
    }

    return configuration;
}


void registerStorageURL(StorageFactory & factory)
{
    factory.registerStorage("URL", [](const StorageFactory::Arguments & args)
    {
        ASTs & engine_args = args.engine_args;
        auto configuration = StorageURL::getConfiguration(engine_args, args.getLocalContext());
        auto format_settings = StorageURL::getFormatSettingsFromArgs(args);
        Poco::URI uri(configuration.url);

        ReadWriteBufferFromHTTP::HTTPHeaderEntries headers;
        for (const auto & [header, value] : configuration.headers)
        {
            auto value_literal = value.safeGet<String>();
            if (header == "Range")
                throw Exception(ErrorCodes::BAD_ARGUMENTS, "Range headers are not allowed");
            headers.emplace_back(std::make_pair(header, value_literal));
        }

        return StorageURL::create(
            uri,
            args.table_id,
            configuration.format,
            format_settings,
            args.columns,
            args.constraints,
            args.comment,
            args.getContext(),
            configuration.compression_method,
            headers);
    },
    {
        .supports_settings = true,
        .source_access_type = AccessType::URL,
    });
}
}