summaryrefslogtreecommitdiffhomepage
path: root/src/nxt_upstream_round_robin.c
blob: 96c3e44e16efca81315bbfdc61a5c5f98c0e6307 (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
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) NGINX, Inc.
 */

#include <math.h>
#include <nxt_router.h>
#include <nxt_http.h>
#include <nxt_upstream.h>


struct nxt_upstream_round_robin_server_s {
    nxt_sockaddr_t                     *sockaddr;

    int32_t                            current_weight;
    int32_t                            effective_weight;
    int32_t                            weight;

    uint8_t                            protocol;
};


struct nxt_upstream_round_robin_s {
    uint32_t                           items;
    nxt_upstream_round_robin_server_t  server[];
};


static nxt_upstream_t *nxt_upstream_round_robin_joint_create(
    nxt_router_temp_conf_t *tmcf, nxt_upstream_t *upstream);
static void nxt_upstream_round_robin_server_get(nxt_task_t *task,
    nxt_upstream_server_t *us);


static const nxt_upstream_server_proto_t  nxt_upstream_round_robin_proto = {
    .joint_create = nxt_upstream_round_robin_joint_create,
    .get          = nxt_upstream_round_robin_server_get,
};


nxt_int_t
nxt_upstream_round_robin_create(nxt_task_t *task, nxt_router_temp_conf_t *tmcf,
    nxt_conf_value_t *upstream_conf, nxt_upstream_t *upstream)
{
    double                      total, k, w;
    size_t                      size;
    uint32_t                    i, n, next, wt;
    nxt_mp_t                    *mp;
    nxt_str_t                   name;
    nxt_sockaddr_t              *sa;
    nxt_conf_value_t            *servers_conf, *srvcf, *wtcf;
    nxt_upstream_round_robin_t  *urr;

    static const nxt_str_t  servers = nxt_string("servers");
    static const nxt_str_t  weight = nxt_string("weight");

    mp = tmcf->router_conf->mem_pool;

    servers_conf = nxt_conf_get_object_member(upstream_conf, &servers, NULL);
    n = nxt_conf_object_members_count(servers_conf);

    total = 0.0;
    next = 0;

    for (i = 0; i < n; i++) {
        srvcf = nxt_conf_next_object_member(servers_conf, &name, &next);
        wtcf = nxt_conf_get_object_member(srvcf, &weight, NULL);
        w = (wtcf != NULL) ? nxt_conf_get_number(wtcf) : 1;
        total += w;
    }

    /*
     * This prevents overflow of int32_t
     * in nxt_upstream_round_robin_server_get().
     */
    k = (total == 0) ? 0 : (NXT_INT32_T_MAX / 2) / total;

    if (isinf(k)) {
        k = 1;
    }

    size = sizeof(nxt_upstream_round_robin_t)
           + n * sizeof(nxt_upstream_round_robin_server_t);

    urr = nxt_mp_zalloc(mp, size);
    if (nxt_slow_path(urr == NULL)) {
        return NXT_ERROR;
    }

    urr->items = n;
    next = 0;

    for (i = 0; i < n; i++) {
        srvcf = nxt_conf_next_object_member(servers_conf, &name, &next);

        sa = nxt_sockaddr_parse(mp, &name);
        if (nxt_slow_path(sa == NULL)) {
            return NXT_ERROR;
        }

        sa->type = SOCK_STREAM;

        urr->server[i].sockaddr = sa;
        urr->server[i].protocol = NXT_HTTP_PROTO_H1;

        wtcf = nxt_conf_get_object_member(srvcf, &weight, NULL);
        w = (wtcf != NULL) ? k * nxt_conf_get_number(wtcf) : k;
        wt = (w > 1 || w == 0) ? round(w) : 1;

        urr->server[i].weight = wt;
        urr->server[i].effective_weight = wt;
    }

    upstream->proto = &nxt_upstream_round_robin_proto;
    upstream->type.round_robin = urr;

    return NXT_OK;
}


static nxt_upstream_t *
nxt_upstream_round_robin_joint_create(nxt_router_temp_conf_t *tmcf,
    nxt_upstream_t *upstream)
{
    size_t                      size;
    uint32_t                    i, n;
    nxt_mp_t                    *mp;
    nxt_upstream_t              *u;
    nxt_upstream_round_robin_t  *urr, *urrcf;

    mp = tmcf->router_conf->mem_pool;

    u = nxt_mp_alloc(mp, sizeof(nxt_upstream_t));
    if (nxt_slow_path(u == NULL)) {
        return NULL;
    }

    *u = *upstream;

    urrcf = upstream->type.round_robin;

    size = sizeof(nxt_upstream_round_robin_t)
           + urrcf->items * sizeof(nxt_upstream_round_robin_server_t);

    urr = nxt_mp_alloc(mp, size);
    if (nxt_slow_path(urr == NULL)) {
        return NULL;
    }

    u->type.round_robin = urr;

    n = urrcf->items;
    urr->items = n;

    for (i = 0; i < n; i++) {
        urr->server[i] = urrcf->server[i];
    }

    return u;
}


static void
nxt_upstream_round_robin_server_get(nxt_task_t *task, nxt_upstream_server_t *us)
{
    int32_t                            total;
    uint32_t                           i, n;
    nxt_upstream_round_robin_t         *round_robin;
    nxt_upstream_round_robin_server_t  *s, *best;

    best = NULL;
    total = 0;

    round_robin = us->upstream->type.round_robin;

    s = round_robin->server;
    n = round_robin->items;

    for (i = 0; i < n; i++) {

        s[i].current_weight += s[i].effective_weight;
        total += s[i].effective_weight;

        if (s[i].effective_weight < s[i].weight) {
            s[i].effective_weight++;
        }

        if (best == NULL || s[i].current_weight > best->current_weight) {
            best = &s[i];
        }
    }

    if (best == NULL || total == 0) {
        us->state->error(task, us);
        return;
    }

    best->current_weight -= total;
    us->sockaddr = best->sockaddr;
    us->protocol = best->protocol;
    us->server.round_robin = best;

    us->state->ready(task, us);
}