ClickHouse/dbms/src/Interpreters/SettingsConstraints.h
2019-04-30 17:09:10 +03:00

92 lines
3.0 KiB
C++

#pragma once
#include <Common/SettingsChanges.h>
#include <Core/Settings.h>
namespace Poco
{
namespace Util
{
class AbstractConfiguration;
}
}
namespace DB
{
struct Settings;
/** Checks if specified changes of settings are allowed or not.
* If the changes are not allowed (i.e. violates some constraints) this class throws an exception.
* The constraints are set by editing the `users.xml` file.
*
* For examples, the following lines in `users.xml` will set that `max_memory_usage` cannot be greater than 20000000000,
* and `force_index_by_date` should be always equal to 0:
*
* <profiles>
* <user_profile>
* <max_memory_usage>10000000000</max_memory_usage>
* <force_index_by_date>0</force_index_by_date>
* ...
* <constraints>
* <max_memory_usage>
* <min>200000</min>
* <max>20000000000</max>
* </max_memory_usage>
* <force_index_by_date>
* <readonly/>
* </force_index_by_date>
* </constraints>
* </user_profile>
* </profiles>
*
* This class also checks that we are not in the read-only mode.
* If a setting cannot be change due to the read-only mode this class throws an exception.
* The value of `readonly` value is understood as follows:
* 0 - everything allowed.
* 1 - only read queries can be made; you can not change the settings.
* 2 - you can only do read queries and you can change the settings, except for the `readonly` setting.
*/
class SettingsConstraints
{
public:
SettingsConstraints();
SettingsConstraints(const SettingsConstraints & src);
SettingsConstraints & operator =(const SettingsConstraints & src);
SettingsConstraints(SettingsConstraints && src);
SettingsConstraints & operator =(SettingsConstraints && src);
~SettingsConstraints();
void clear();
void setMinValue(const String & name, const Field & min_value);
void setMaxValue(const String & name, const Field & max_value);
void setReadOnly(const String & name, bool read_only);
void check(const Settings & current_settings, const SettingChange & change) const;
void check(const Settings & current_settings, const SettingsChanges & changes) const;
/** Set multiple settings from "profile" (in server configuration file (users.xml), profiles contain groups of multiple settings).
* The profile can also be set using the `set` functions, like the profile setting.
*/
void setProfile(const String & profile_name, const Poco::Util::AbstractConfiguration & config);
/// Loads the constraints from configuration file, at "path" prefix in configuration.
void loadFromConfig(const String & path, const Poco::Util::AbstractConfiguration & config);
private:
struct Constraint
{
bool read_only = false;
Field min_value;
Field max_value;
};
Constraint & getConstraintRef(size_t index);
const Constraint * tryGetConstraint(size_t) const;
std::unordered_map<size_t, Constraint> constraints_by_index;
};
}