elasticsearch.transport.connections.connection source code

1 module elasticsearch.transport.connections.connection;
2 
3 import elasticsearch.transport.transport;
4 import elasticsearch.api.parameters;
5 import std.datetime;
6 
7 /**
8  * Wraps the connection information and logic.
9  * 
10  * The Connection instance wraps the host information (hostname, port, attributes, etc),
11  * as well as the "session" (a transport client object, such as a {elasticsearch.transport.http.vibe} instance).
12  *
13  * It provides methods to construct and properly encode the URLs and paths for passing them
14  * to the transport client object.
15  *
16  * It provides methods to handle connection lifecycle (dead, alive, healthy).
17  */
18 
19 class Connection {
20 	package {
21 		Host _host;
22 		Transport _connection;
23 		int _resurrectTimeout = 60; // Seconds
24 		int _failures = 0;
25 		bool _dead = false;
26 		SysTime _deadSince;
27 
28 	}
29 
30 	this(Host host, Transport connection, int resurrectTimeout = 60) {
31 		_host = host;
32 		_connection = connection;
33 	}
34 
35 	@property Host host() { return _host; }
36 	@property ref int resurrectTimeout() { return _resurrectTimeout; }
37 	@property bool dead() { return _dead; }
38 	@property SysTime deadSince() { return _deadSince; }
39 	@property bool alive() { return !_dead; }
40 	@property int failures() { return _failures; }
41 	@property bool resurrectable() {
42 		import std.math;
43 		return Clock.currTime > (_deadSince + dur!"seconds"(_resurrectTimeout * pow(2, _failures - 1)));
44 	}
45 	
46 	/**
47 	 * Marks this connection as dead, incrementing the `failures` counter and
48 	 * storing the current time as `dead_since`.
49 	 */
50 	Connection makeDead() { 
51 		_dead = true;
52 		_failures++;
53 		_deadSince = Clock.currTime;
54 		return this;
55 	}
56 
57 	/// Marks this connection as alive, ie. it is eligible to be returned from the pool by the selector.
58 	Connection makeAlive() {
59 		_dead = false;
60 		return this;
61 	}
62 
63 	/// Marks this connection as healthy, ie. a request has been successfully performed with it.
64 	Connection makeHealthy() {
65 		makeAlive();
66 		_failures = 0;
67 		return this;
68 	}
69 
70 	/// Marks this connection as alive, if the required timeout has passed.
71 	Connection resurrect() {
72 		if (resurrectable) makeAlive();
73 		return this;
74 	}
75 
76 	/// Returns the complete endpoint URL with host, port, path and serialized parameters.
77 	string fullURL(string path, ESParams params) {
78 		import std.conv;
79 
80 		auto url = host.url;
81 		url ~= "/" ~ fullPath(path, params);
82 
83 		return url;
84 	}
85 
86 	string fullPath(string path, ESParams params) {
87 		import std.array;
88 		import std.uri;
89 
90 		auto returnPath = path;
91 
92 		if (params.length) {
93 			string[] paramArray;
94 
95 			foreach(key, value; params)
96 				paramArray ~= encodeComponent(key) ~ "=" ~ encodeComponent(value);
97 			returnPath ~= "?" ~ join(paramArray, "&");
98 		}
99 
100 		return returnPath;
101 	}
102 
103 	override string toString() {
104 		auto returnString = "<Connection host: " ~ _host.hostName;
105 		returnString ~= " " ~ (_dead ? ("dead since " ~ _deadSince.toString()) : "alive");
106 		returnString ~= ">";
107 		return returnString;
108 	}
109 }
110 
111 unittest {
112 	import elasticsearch.transport.http.vibe;
113 
114 	auto host = Host();
115 	auto c = new Connection(host, new VibeTransport());
116 
117 	assert(c.alive);
118 	assert(c.makeDead.dead);
119 	assert(c.failures == 1);
120 	assert(!c.resurrectable);
121 	assert(c.resurrect.dead);
122 	c._deadSince = Clock.currTime - dur!"minutes"(2);
123 	assert(c.resurrectable);
124 	assert(c.resurrect.alive);
125 	assert(c.failures == 1);
126 	assert(c.makeHealthy.failures == 0);
127 }