ClickHouse/src/Access/SettingsConstraints.h
2021-11-02 14:06:20 +03:00

116 lines
4.2 KiB
C++

#pragma once
#include <Common/SettingsChanges.h>
#include <unordered_map>
namespace Poco::Util
{
class AbstractConfiguration;
}
namespace DB
{
struct Settings;
struct SettingChange;
class SettingsChanges;
class AccessControl;
/** 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(const AccessControl & access_control_);
SettingsConstraints(const SettingsConstraints & src);
SettingsConstraints & operator =(const SettingsConstraints & src);
SettingsConstraints(SettingsConstraints && src);
SettingsConstraints & operator =(SettingsConstraints && src);
~SettingsConstraints();
void clear();
bool empty() const { return constraints.empty(); }
void setMinValue(const std::string_view & setting_name, const Field & min_value);
Field getMinValue(const std::string_view & setting_name) const;
void setMaxValue(const std::string_view & setting_name, const Field & max_value);
Field getMaxValue(const std::string_view & setting_name) const;
void setReadOnly(const std::string_view & setting_name, bool read_only);
bool isReadOnly(const std::string_view & setting_name) const;
void set(const std::string_view & setting_name, const Field & min_value, const Field & max_value, bool read_only);
void get(const std::string_view & setting_name, Field & min_value, Field & max_value, bool & read_only) const;
void merge(const SettingsConstraints & other);
/// Checks whether `change` violates these constraints and throws an exception if so.
void check(const Settings & current_settings, const SettingChange & change) const;
void check(const Settings & current_settings, const SettingsChanges & changes) const;
void check(const Settings & current_settings, SettingsChanges & changes) const;
/// Checks whether `change` violates these and clamps the `change` if so.
void clamp(const Settings & current_settings, SettingsChanges & changes) const;
friend bool operator ==(const SettingsConstraints & left, const SettingsConstraints & right);
friend bool operator !=(const SettingsConstraints & left, const SettingsConstraints & right) { return !(left == right); }
private:
struct Constraint
{
std::shared_ptr<const String> setting_name;
bool read_only = false;
Field min_value;
Field max_value;
bool operator ==(const Constraint & other) const;
bool operator !=(const Constraint & other) const { return !(*this == other); }
};
enum ReactionOnViolation
{
THROW_ON_VIOLATION,
CLAMP_ON_VIOLATION,
};
bool checkImpl(const Settings & current_settings, SettingChange & change, ReactionOnViolation reaction) const;
Constraint & getConstraintRef(const std::string_view & setting_name);
const Constraint * tryGetConstraint(const std::string_view & setting_name) const;
std::unordered_map<std::string_view, Constraint> constraints;
const AccessControl * access_control = nullptr;
};
}