blob: 8bdd8d5832cc07fee3833407ec4284b51bbc3853 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
//
#pragma once
#include "subscriptionid.h"
#include <vespa/vespalib/util/time.h>
#include <atomic>
#include <memory>
#include <vector>
#include <condition_variable>
namespace config {
class IConfigContext;
class IConfigManager;
class ConfigSubscription;
class ConfigKey;
/**
* A ConfigSubscriptionSet is a set of configs that can be subscribed to.
*/
class ConfigSubscriptionSet
{
public:
/**
* Constructs a new ConfigSubscriptionSet object which can be used to subscribe for 1
* or more configs from a specific source.
*
* @param context A ConfigContext shared between all subscriptions.
*/
explicit ConfigSubscriptionSet(std::shared_ptr<IConfigContext> context);
ConfigSubscriptionSet(const ConfigSubscriptionSet &) = delete;
ConfigSubscriptionSet & operator= (const ConfigSubscriptionSet &) = delete;
~ConfigSubscriptionSet();
/**
* Return the current generation number for configs.
*
* @return generation number
*/
int64_t getGeneration() const noexcept {
return _currentGeneration.load(std::memory_order_relaxed);
}
/**
* Closes the set, which will interrupt acquireSnapshot and unsubscribe all
* configs currently subscribed for.
*/
void close();
/**
* Checks if this subscription set is closed.
*/
bool isClosed() const noexcept {
return (_state.load(std::memory_order_relaxed) == CLOSED);
}
// Helpers for doing the subscription
std::shared_ptr<ConfigSubscription> subscribe(const ConfigKey & key, vespalib::duration timeout);
// Tries to acquire a new snapshot of config within the timeout
bool acquireSnapshot(vespalib::duration timeout, bool requireDifference);
private:
// Describes the state of the subscriber.
enum SubscriberState { OPEN, FROZEN, CONFIGURED, CLOSED };
using SubscriptionList = std::vector<std::shared_ptr<ConfigSubscription>>;
const vespalib::duration _maxNapTime;
std::shared_ptr<IConfigContext> _context; // Context to keep alive managers.
IConfigManager & _mgr; // The config manager that we use.
std::atomic<int64_t> _currentGeneration; // Holds the current config generation.
SubscriptionList _subscriptionList; // List of current subscriptions.
std::atomic<SubscriberState> _state; // Current state of this subscriber.
std::mutex _lock;
std::condition_variable _cond;
};
} // namespace config
|
