MySQL 8.3.0
Source Code Documentation
plugin_config.h
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1/*
2 Copyright (c) 2015, 2023, Oracle and/or its affiliates.
3
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17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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23*/
24
25#ifndef MYSQL_HARNESS_PLUGIN_CONFIG_INCLUDED
26#define MYSQL_HARNESS_PLUGIN_CONFIG_INCLUDED
27
28#include <chrono>
29#include <limits>
30#include <optional>
31#include <string>
32
33#include "harness_export.h"
36
37namespace mysql_harness {
38
39/** Exception that gets thrown when the configuration option is missing
40 */
41class option_not_present : public std::invalid_argument {
42 public:
43 using std::invalid_argument::invalid_argument;
44};
45
46/** Exception that gets thrown when the configuration option is present
47 * but it is empty value
48 */
49class option_empty : public std::invalid_argument {
50 public:
51 using std::invalid_argument::invalid_argument;
52};
53
54/**
55 * Retrieve and manage plugin configuration.
56 *
57 * BasePluginConfig is an abstract class which can be used to by plugins
58 * to derive their own class retrieving configuration from, for example,
59 * Harness `ConfigSection instances`.
60 */
61class HARNESS_EXPORT BasePluginConfig {
62 public:
63 BasePluginConfig() = default;
64
67
70
71 /**
72 * destructor
73 */
74 virtual ~BasePluginConfig() = default;
75
76 /**
77 * get description of the option.
78 *
79 * For example, option wait_timeout in section [routing:homepage] will
80 * return a prefix (without quotes):
81 *
82 * option wait_timeout in [routing:homepage]
83 *
84 * @param section configuration section
85 * @param option Name of the option
86 *
87 * @return Prefix as std::string
88 */
89 std::string get_option_description(
90 const mysql_harness::ConfigSection *section,
91 const std::string &option) const;
92
93 /**
94 * Gets the default for the given option.
95 *
96 * Gets the default value of the given option. If no default option
97 * is available, an empty string is returned.
98 *
99 * @param option name of the option
100 * @return default value for given option as std::string
101 */
102 virtual std::string get_default(const std::string &option) const = 0;
103
104 /**
105 * Returns whether the given option is required.
106 *
107 * @return bool
108 */
109 virtual bool is_required(const std::string &option) const = 0;
110
111 /**
112 * get option value.
113 *
114 * gets the option from a config-section (or its default value if it doesn't
115 * exist) and converts it with a transformation function.
116 *
117 * @param section configuration section
118 * @param option name of the option
119 * @param transformer transformation function. The signature of the
120 * transformation function should be equivalent to:
121 * @c (const std::string &value, const std::string &option_description)
122 * and returns the transformed value.
123 * @returns return value of the the transformation function.
124 */
125 template <class Func>
126 decltype(auto) get_option(const mysql_harness::ConfigSection *section,
127 const std::string &option,
128 Func &&transformer) const {
129 const auto value = get_option_string_or_default_(section, option);
130
131 return transformer(value, get_option_description(section, option));
132 }
133
134 /**
135 * get option value.
136 *
137 * gets the option from a config-section and converts it with a transformation
138 * function.
139 *
140 * does not call get_default().
141 *
142 * @param section configuration section
143 * @param option name of the option
144 * @param transformer transformation function. The signature of the
145 * transformation function should be equivalent to:
146 * @c (const std::string &value, const std::string &option_description)
147 * and returns the transformed value.
148 * @returns transformed value.
149 */
150 template <class Func>
151 decltype(auto) get_option_no_default(
152 const mysql_harness::ConfigSection *section, const std::string &option,
153 Func &&transformer) const {
154 const auto value = get_option_string_(section, option);
155
156 return transformer(value, get_option_description(section, option));
157 }
158
159 /**
160 * Gets value of given option as string.
161 *
162 * @throws option_not_present if the required option is missing
163 * @throws option_empty if the required option is present but empty
164 *
165 * @param section Instance of ConfigSection
166 * @param option name of the option
167 * @return Option value as std::string
168 *
169 */
170 [[deprecated("use get_option(..., StringOption{}) instead")]]
171 // line-break
172 std::string
174 const std::string &option) const {
175 return get_option(section, option,
176 [](auto const &value, auto const &) { return value; });
177 }
178
179 /**
180 * Gets an unsigned integer using the given option.
181 *
182 * Gets an unsigned integer using the given option. The type can be
183 * any unsigned integer type such as uint16_t.
184 *
185 * The min_value argument can be used to set a minimum value for
186 * the option. For example, when 0 (zero) is not allowed, min_value
187 * can be set to 0. The maximum value is whatever the maximum of the
188 * use type is.
189 *
190 * Throws std::invalid_argument on errors.
191 *
192 * @param section Instance of ConfigSection
193 * @param option Option name in section
194 * @param min_value Minimum value
195 * @param max_value Maximum value
196 * @return value read from the configuration
197 */
198 template <class T>
199 [[deprecated("used get_option(..., IntOption<T>{}) instead")]]
200 // line-break
202 const std::string &option, T min_value = 0,
203 T max_value = std::numeric_limits<T>::max()) const {
204 return get_option(section, option, IntOption<T>{min_value, max_value});
205 }
206
207 /**
208 * Gets a number of milliseconds using the given option.
209 *
210 * The expected option value is a string with floating point number in seconds
211 * (with '.' as a decimal separator) in standard or scientific notation
212 *
213 * - for value = "1.0" expected result is std::chrono:milliseconds(1000)
214 * - for value = "0.01" expected result is std::chrono:milliseconds(10)
215 * - for value = "1.6E-2" expected result is std::chrono:milliseconds(16)
216 *
217 * @param section Instance of ConfigSection
218 * @param option Option name in section
219 * @param min_value Minimum value
220 * @param max_value Maximum value
221 *
222 * @return value converted to milliseconds
223 * @throws std::invalid_argument on errors
224 */
225 [[deprecated("used get_option(..., MilliSecondsOption{}) instead")]]
226 // line-break
227 std::chrono::milliseconds
229 const mysql_harness::ConfigSection *section, const std::string &option,
230 double min_value = 0.0,
231 double max_value = std::numeric_limits<double>::max()) const {
232 return get_option(section, option,
233 MilliSecondsOption{min_value, max_value});
234 }
235
236 protected:
237 /**
238 * Constructor for derived classes.
239 */
241 : section_name_{get_section_name(section)} {}
242
243 /**
244 * Generate the name for this configuration.
245 *
246 * @param section Instance of ConfigSection
247 * @return the name for this configuration
248 */
249 static std::string get_section_name(
250 const mysql_harness::ConfigSection *section);
251
252 private:
253 /**
254 * Name of the section
255 */
256 std::string section_name_;
257
258 /**
259 * get value of an option from a config-section.
260 *
261 * does not call get_default()
262 *
263 * @return a value of the option if it exists.
264 */
265 std::optional<std::string> get_option_string_(
266 const mysql_harness::ConfigSection *section,
267 const std::string &option) const;
268
269 /**
270 * get value of an option from a config-section.
271 *
272 * gets value from get_default() if the option-value
273 * is not present or empty.
274 *
275 * @return a value of the option if it exists.
276 */
277 std::string get_option_string_or_default_(
278 const mysql_harness::ConfigSection *section,
279 const std::string &option) const;
280};
281
282} // namespace mysql_harness
283
284#endif // MYSQL_HARNESS_PLUGIN_CONFIG_INCLUDED
Retrieve and manage plugin configuration.
Definition: plugin_config.h:61
std::chrono::milliseconds get_option_milliseconds(const mysql_harness::ConfigSection *section, const std::string &option, double min_value=0.0, double max_value=std::numeric_limits< double >::max()) const
Gets a number of milliseconds using the given option.
Definition: plugin_config.h:228
T get_uint_option(const mysql_harness::ConfigSection *section, const std::string &option, T min_value=0, T max_value=std::numeric_limits< T >::max()) const
Gets an unsigned integer using the given option.
Definition: plugin_config.h:201
BasePluginConfig(const mysql_harness::ConfigSection *section)
Constructor for derived classes.
Definition: plugin_config.h:240
std::string get_option_string(const mysql_harness::ConfigSection *section, const std::string &option) const
Gets value of given option as string.
Definition: plugin_config.h:173
decltype(auto) get_option_no_default(const mysql_harness::ConfigSection *section, const std::string &option, Func &&transformer) const
get option value.
Definition: plugin_config.h:151
BasePluginConfig & operator=(BasePluginConfig &&)=default
BasePluginConfig(BasePluginConfig &&)=default
virtual bool is_required(const std::string &option) const =0
Returns whether the given option is required.
BasePluginConfig(const BasePluginConfig &)=default
std::string section_name_
Name of the section.
Definition: plugin_config.h:256
decltype(auto) get_option(const mysql_harness::ConfigSection *section, const std::string &option, Func &&transformer) const
get option value.
Definition: plugin_config.h:126
virtual std::string get_default(const std::string &option) const =0
Gets the default for the given option.
virtual ~BasePluginConfig()=default
destructor
BasePluginConfig & operator=(const BasePluginConfig &)=default
Configuration section.
Definition: config_parser.h:140
Definition: config_option.h:167
Definition: config_option.h:107
Exception that gets thrown when the configuration option is present but it is empty value.
Definition: plugin_config.h:49
Exception that gets thrown when the configuration option is missing.
Definition: plugin_config.h:41
static std::string get_option(const mysql_harness::ConfigSection *section, const std::string &key, const std::string &def_value)
Definition: metadata_cache_plugin.cc:110
Definition: common.h:41