ClickHouse/dbms/include/DB/Common/ConfigProcessor.h
2017-03-19 21:58:12 +04:00

120 lines
4.2 KiB
C++

#pragma once
#include <string>
#include <unordered_set>
#include <Poco/DOM/Document.h>
#include <Poco/DOM/DOMParser.h>
#include <Poco/DOM/DOMWriter.h>
#include <Poco/DOM/NodeList.h>
#include <Poco/DOM/NamedNodeMap.h>
#include <Poco/AutoPtr.h>
#include <Poco/File.h>
#include <Poco/Path.h>
#include <Poco/DirectoryIterator.h>
#include <Poco/ConsoleChannel.h>
#include <Poco/Util/AbstractConfiguration.h>
#include <common/logger_useful.h>
namespace zkutil
{
class ZooKeeperNodeCache;
}
using ConfigurationPtr = Poco::AutoPtr<Poco::Util::AbstractConfiguration>;
using XMLDocumentPtr = Poco::AutoPtr<Poco::XML::Document>;
class ConfigProcessor
{
public:
using Substitutions = std::vector<std::pair<std::string, std::string> >;
/// Set log_to_console to true if the logging subsystem is not initialized yet.
ConfigProcessor(bool throw_on_bad_incl = false, bool log_to_console = false, const Substitutions & substitutions = Substitutions());
~ConfigProcessor();
/// Perform config includes and substitutions and return the resulting XML-document.
///
/// Suppose path is "/path/file.xml"
/// 1) Merge XML trees of /path/file.xml with XML trees of all files from /path/{conf,file}.d/*.{conf,xml}
/// * If an element has a "replace" attribute, replace the matching element with it.
/// * If an element has a "remove" attribute, remove the matching element.
/// * Else, recursively merge child elements.
/// 2) Determine the includes file from the config: <include_from>/path2/metrika.xml</include_from>
/// If this path is not configured, use /etc/metrika.xml
/// 3) Replace elements matching the "<foo incl="bar"/>" pattern with
/// "<foo>contents of the yandex/bar element in metrika.xml</foo>"
/// 4) If zk_node_cache is non-NULL, replace elements matching the "<foo from_zk="/bar">" pattern with
/// "<foo>contents of the /bar ZooKeeper node</foo>".
/// If has_zk_includes is non-NULL and there are such elements, set has_zk_includes to true.
/// 5) (Yandex.Metrika-specific) Substitute "<layer/>" with "<layer>layer number from the hostname</layer>".
XMLDocumentPtr processConfig(
const std::string & path,
bool * has_zk_includes = nullptr,
zkutil::ZooKeeperNodeCache * zk_node_cache = nullptr);
/// loadConfig* functions apply processConfig and create Poco::Util::XMLConfiguration.
/// The resulting XML document is saved into a file with the name
/// resulting from adding "-preprocessed" suffix to the path file name.
/// E.g., config.xml -> config-preprocessed.xml
struct LoadedConfig
{
ConfigurationPtr configuration;
bool has_zk_includes;
bool loaded_from_preprocessed;
bool preprocessed_written;
};
/// If allow_zk_includes is true, expect that the configuration XML can contain from_zk nodes.
/// If it is the case, set has_zk_includes to true and don't write config-preprocessed.xml,
/// expecting that config would be reloaded with zookeeper later.
LoadedConfig loadConfig(const std::string & path, bool allow_zk_includes = false);
/// If fallback_to_preprocessed is true, then if KeeperException is thrown during config
/// processing, load the configuration from the preprocessed file.
LoadedConfig loadConfigWithZooKeeperIncludes(
const std::string & path,
zkutil::ZooKeeperNodeCache & zk_node_cache,
bool fallback_to_preprocessed = false);
public:
using Files = std::list<std::string>;
static Files getConfigMergeFiles(const std::string & config_path);
private:
bool throw_on_bad_incl;
Logger * log;
Poco::AutoPtr<Poco::Channel> channel_ptr;
Substitutions substitutions;
Poco::AutoPtr<Poco::XML::NamePool> name_pool;
Poco::XML::DOMParser dom_parser;
private:
using NodePtr = Poco::AutoPtr<Poco::XML::Node>;
void mergeRecursive(XMLDocumentPtr config, Poco::XML::Node * config_node, Poco::XML::Node * with_node);
void merge(XMLDocumentPtr config, XMLDocumentPtr with);
std::string layerFromHost();
void doIncludesRecursive(
XMLDocumentPtr config,
XMLDocumentPtr include_from,
Poco::XML::Node * node,
zkutil::ZooKeeperNodeCache * zk_node_cache,
std::unordered_set<std::string> & contributing_zk_paths);
void savePreprocessedConfig(const XMLDocumentPtr & config, const std::string & preprocessed_path);
};