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1 /*
2  * lws System Metrics
3  *
4  * Copyright (C) 2021 Andy Green <andy@warmcat.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to
8  * deal in the Software without restriction, including without limitation the
9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10  * sell copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22  * IN THE SOFTWARE.
23  */
24 
25 /*
26  * Const struct that describes a policy for processing raw metrics to turn them
27  * into events.
28  *
29  * Typically although we want to monitor every event, the data produced can be
30  * too large, and many events that are "normal" just need to be counted as such;
31  * outliers or change-to-continuous outliers may deserve closer recording as
32  * events in their own right.
33  *
34  * Mean computation must "decay" as it ages, we do this by halving the sum and
35  * count after .us_decay_unit us.
36  *
37  * We don't acknowledge outliers until there are at least .min_contributors
38  * in the current mean (which is subject to decaying)
39  *
40  * We decide something is an outlier event if it deviates from the mean by
41  * .pc_outlier_deviation %.
42  */
43 
44 /*
45  * The dynamic counterpart for each static metric policy, this is on heap
46  * one per const lws_metric_policy_t.  It's listed in context->owner_mtr_dynpol
47  */
48 
49 typedef struct lws_metric_policy_dyn {
50 	const lws_metric_policy_t	*policy;
51 	/**< the static part of the policy we belong to... can be NULL if no
52 	 * policy matches or the policy was invalidated */
53 
54 	lws_dll2_owner_t		owner;
55 	/**< list of metrics that are using this policy */
56 
57 	lws_dll2_t			list;
58 	/**< context owns us */
59 
60 	lws_sorted_usec_list_t		sul;
61 	/**< schedule periodic reports for metrics using this policy */
62 } lws_metric_policy_dyn_t;
63 
64 /*
65  * A metrics private part, encapsulating the public part
66  */
67 
68 typedef struct lws_metric {
69 
70 	lws_dll2_t			list;
71 	/**< owned by either 1) ctx.lws_metric_policy_dyn_t.owner, or
72 	 * 2) ctx.owner_mtr_no_pol */
73 
74 	struct lws_context		*ctx;
75 
76 	/* public part overallocated */
77 } lws_metric_t;
78 
79 
80 #if defined(LWS_WITH_SYS_METRICS)
81 #define lws_metrics_hist_bump_priv(_mt, _name) \
82 		lws_metrics_hist_bump_(lws_metrics_priv_to_pub(_mt), _name)
83 #define lws_metrics_hist_bump_priv_wsi(_wsi, _hist, _name) \
84 		lws_metrics_hist_bump_(lws_metrics_priv_to_pub(_wsi->a.context->_hist), _name)
85 #define lws_metrics_hist_bump_priv_ss(_ss, _hist, _name) \
86 		lws_metrics_hist_bump_(lws_metrics_priv_to_pub(_ss->context->_hist), _name)
87 #define lws_metrics_priv_to_pub(_x) ((lws_metric_pub_t *)&(_x)[1])
88 #else
89 #define lws_metrics_hist_bump_priv(_mt, _name)
90 #define lws_metrics_hist_bump_priv_wsi(_wsi, _hist, _name)
91 #define lws_metrics_hist_bump_priv_ss(_ss, _hist, _name)
92 #define lws_metrics_priv_to_pub(_x) ((lws_metric_pub_t *)NULL)
93 #endif
94 
95 #if defined(LWS_WITH_SECURE_STREAMS_PROXY_API)
96 /*
97  * sspc-specific version that also appends the tag value to the lifecycle tag
98  * used for logging the sspc identity
99  */
100 int
101 lws_metrics_tag_sspc_add(struct lws_sspc_handle *ss, const char *name, const char *val);
102 #endif
103 
104 int
105 lws_metrics_register_policy(struct lws_context *ctx,
106 			    const lws_metric_policy_t *head);
107 
108 void
109 lws_metrics_destroy(struct lws_context *ctx);
110 
111 void
112 lws_metric_event(lws_metric_t *mt, char go_nogo, u_mt_t val);
113 
114 lws_metric_t *
115 lws_metric_create(struct lws_context *ctx, uint8_t flags, const char *name);
116 
117 int
118 lws_metric_destroy(lws_metric_t **mt, int keep);
119 
120 void
121 lws_metric_policy_dyn_destroy(lws_metric_policy_dyn_t *dm, int keep);
122 
123 void
124 lws_metric_rebind_policies(struct lws_context *ctx);
125