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
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
|
<!DOCTYPE HTML>
<html lang="en" class="sidebar-visible no-js light">
<head>
<!-- Book generated using mdBook -->
<meta charset="UTF-8">
<title>OpenTracing - Synapse</title>
<!-- Custom HTML head -->
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
<meta name="description" content="">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="theme-color" content="#ffffff" />
<link rel="icon" href="favicon.svg">
<link rel="shortcut icon" href="favicon.png">
<link rel="stylesheet" href="css/variables.css">
<link rel="stylesheet" href="css/general.css">
<link rel="stylesheet" href="css/chrome.css">
<link rel="stylesheet" href="css/print.css" media="print">
<!-- Fonts -->
<link rel="stylesheet" href="FontAwesome/css/font-awesome.css">
<link rel="stylesheet" href="fonts/fonts.css">
<!-- Highlight.js Stylesheets -->
<link rel="stylesheet" href="highlight.css">
<link rel="stylesheet" href="tomorrow-night.css">
<link rel="stylesheet" href="ayu-highlight.css">
<!-- Custom theme stylesheets -->
<link rel="stylesheet" href="docs/website_files/table-of-contents.css">
<link rel="stylesheet" href="docs/website_files/remove-nav-buttons.css">
<link rel="stylesheet" href="docs/website_files/indent-section-headers.css">
</head>
<body>
<!-- Provide site root to javascript -->
<script type="text/javascript">
var path_to_root = "";
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "light";
</script>
<!-- Work around some values being stored in localStorage wrapped in quotes -->
<script type="text/javascript">
try {
var theme = localStorage.getItem('mdbook-theme');
var sidebar = localStorage.getItem('mdbook-sidebar');
if (theme.startsWith('"') && theme.endsWith('"')) {
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
}
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
}
} catch (e) { }
</script>
<!-- Set the theme before any content is loaded, prevents flash -->
<script type="text/javascript">
var theme;
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
if (theme === null || theme === undefined) { theme = default_theme; }
var html = document.querySelector('html');
html.classList.remove('no-js')
html.classList.remove('light')
html.classList.add(theme);
html.classList.add('js');
</script>
<!-- Hide / unhide sidebar before it is displayed -->
<script type="text/javascript">
var html = document.querySelector('html');
var sidebar = 'hidden';
if (document.body.clientWidth >= 1080) {
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
sidebar = sidebar || 'visible';
}
html.classList.remove('sidebar-visible');
html.classList.add("sidebar-" + sidebar);
</script>
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
<div class="sidebar-scrollbox">
<ol class="chapter"><li class="chapter-item expanded affix "><li class="part-title">Introduction</li><li class="chapter-item expanded "><a href="welcome_and_overview.html">Welcome and Overview</a></li><li class="chapter-item expanded affix "><li class="part-title">Setup</li><li class="chapter-item expanded "><a href="setup/installation.html">Installation</a></li><li class="chapter-item expanded "><a href="postgres.html">Using Postgres</a></li><li class="chapter-item expanded "><a href="reverse_proxy.html">Configuring a Reverse Proxy</a></li><li class="chapter-item expanded "><a href="turn-howto.html">Configuring a Turn Server</a></li><li class="chapter-item expanded "><a href="delegate.html">Delegation</a></li><li class="chapter-item expanded affix "><li class="part-title">Upgrading</li><li class="chapter-item expanded "><a href="upgrading/index.html">Upgrading between Synapse Versions</a></li><li class="chapter-item expanded "><a href="MSC1711_certificates_FAQ.html">Upgrading from pre-Synapse 1.0</a></li><li class="chapter-item expanded affix "><li class="part-title">Usage</li><li class="chapter-item expanded "><a href="federate.html">Federation</a></li><li class="chapter-item expanded "><a href="usage/configuration/index.html">Configuration</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="usage/configuration/homeserver_sample_config.html">Homeserver Sample Config File</a></li><li class="chapter-item expanded "><a href="usage/configuration/logging_sample_config.html">Logging Sample Config File</a></li><li class="chapter-item expanded "><a href="structured_logging.html">Structured Logging</a></li><li class="chapter-item expanded "><a href="usage/configuration/user_authentication/index.html">User Authentication</a></li><li><ol class="section"><li class="chapter-item expanded "><div>Single-Sign On</div></li><li><ol class="section"><li class="chapter-item expanded "><a href="openid.html">OpenID Connect</a></li><li class="chapter-item expanded "><div>SAML</div></li><li class="chapter-item expanded "><div>CAS</div></li><li class="chapter-item expanded "><a href="sso_mapping_providers.html">SSO Mapping Providers</a></li></ol></li><li class="chapter-item expanded "><a href="password_auth_providers.html">Password Auth Providers</a></li><li class="chapter-item expanded "><a href="jwt.html">JSON Web Tokens</a></li></ol></li><li class="chapter-item expanded "><a href="CAPTCHA_SETUP.html">Registration Captcha</a></li><li class="chapter-item expanded "><a href="application_services.html">Application Services</a></li><li class="chapter-item expanded "><a href="server_notices.html">Server Notices</a></li><li class="chapter-item expanded "><a href="consent_tracking.html">Consent Tracking</a></li><li class="chapter-item expanded "><a href="url_previews.html">URL Previews</a></li><li class="chapter-item expanded "><a href="user_directory.html">User Directory</a></li><li class="chapter-item expanded "><a href="message_retention_policies.html">Message Retention Policies</a></li><li class="chapter-item expanded "><div>Pluggable Modules</div></li><li><ol class="section"><li class="chapter-item expanded "><div>Third Party Rules</div></li><li class="chapter-item expanded "><a href="spam_checker.html">Spam Checker</a></li><li class="chapter-item expanded "><a href="presence_router_module.html">Presence Router</a></li><li class="chapter-item expanded "><div>Media Storage Providers</div></li></ol></li><li class="chapter-item expanded "><a href="workers.html">Workers</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="synctl_workers.html">Using synctl with Workers</a></li><li class="chapter-item expanded "><a href="systemd-with-workers/index.html">Systemd</a></li></ol></li></ol></li><li class="chapter-item expanded "><a href="usage/administration/index.html">Administration</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="usage/administration/admin_api/index.html">Admin API</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="admin_api/account_validity.html">Account Validity</a></li><li class="chapter-item expanded "><a href="admin_api/delete_group.html">Delete Group</a></li><li class="chapter-item expanded "><a href="admin_api/event_reports.html">Event Reports</a></li><li class="chapter-item expanded "><a href="admin_api/media_admin_api.html">Media</a></li><li class="chapter-item expanded "><a href="admin_api/purge_history_api.html">Purge History</a></li><li class="chapter-item expanded "><a href="admin_api/purge_room.html">Purge Rooms</a></li><li class="chapter-item expanded "><a href="admin_api/register_api.html">Register Users</a></li><li class="chapter-item expanded "><a href="admin_api/room_membership.html">Manipulate Room Membership</a></li><li class="chapter-item expanded "><a href="admin_api/rooms.html">Rooms</a></li><li class="chapter-item expanded "><a href="admin_api/server_notices.html">Server Notices</a></li><li class="chapter-item expanded "><a href="admin_api/shutdown_room.html">Shutdown Room</a></li><li class="chapter-item expanded "><a href="admin_api/statistics.html">Statistics</a></li><li class="chapter-item expanded "><a href="admin_api/user_admin_api.html">Users</a></li><li class="chapter-item expanded "><a href="admin_api/version_api.html">Server Version</a></li></ol></li><li class="chapter-item expanded "><a href="manhole.html">Manhole</a></li><li class="chapter-item expanded "><a href="metrics-howto.html">Monitoring</a></li><li class="chapter-item expanded "><div>Scripts</div></li></ol></li><li class="chapter-item expanded "><li class="part-title">Development</li><li class="chapter-item expanded "><a href="development/contributing_guide.html">Contributing Guide</a></li><li class="chapter-item expanded "><a href="code_style.html">Code Style</a></li><li class="chapter-item expanded "><a href="dev/git.html">Git Usage</a></li><li class="chapter-item expanded "><div>Testing</div></li><li class="chapter-item expanded "><a href="opentracing.html" class="active">OpenTracing</a></li><li class="chapter-item expanded "><a href="development/database_schema.html">Database Schemas</a></li><li class="chapter-item expanded "><div>Synapse Architecture</div></li><li><ol class="section"><li class="chapter-item expanded "><a href="log_contexts.html">Log Contexts</a></li><li class="chapter-item expanded "><a href="replication.html">Replication</a></li><li class="chapter-item expanded "><a href="tcp_replication.html">TCP Replication</a></li></ol></li><li class="chapter-item expanded "><a href="development/internal_documentation/index.html">Internal Documentation</a></li><li><ol class="section"><li class="chapter-item expanded "><div>Single Sign-On</div></li><li><ol class="section"><li class="chapter-item expanded "><a href="dev/saml.html">SAML</a></li><li class="chapter-item expanded "><a href="dev/cas.html">CAS</a></li></ol></li><li class="chapter-item expanded "><div>State Resolution</div></li><li><ol class="section"><li class="chapter-item expanded "><a href="auth_chain_difference_algorithm.html">The Auth Chain Difference Algorithm</a></li></ol></li><li class="chapter-item expanded "><a href="media_repository.html">Media Repository</a></li><li class="chapter-item expanded "><a href="room_and_user_statistics.html">Room and User Statistics</a></li></ol></li><li class="chapter-item expanded "><div>Scripts</div></li><li class="chapter-item expanded affix "><li class="part-title">Other</li><li class="chapter-item expanded "><a href="deprecation_policy.html">Dependency Deprecation Policy</a></li></ol>
</div>
<div id="sidebar-resize-handle" class="sidebar-resize-handle"></div>
</nav>
<div id="page-wrapper" class="page-wrapper">
<div class="page">
<div id="menu-bar-hover-placeholder"></div>
<div id="menu-bar" class="menu-bar sticky bordered">
<div class="left-buttons">
<button id="sidebar-toggle" class="icon-button" type="button" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
<i class="fa fa-bars"></i>
</button>
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
<i class="fa fa-paint-brush"></i>
</button>
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
<li role="none"><button role="menuitem" class="theme" id="light">Light (default)</button></li>
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
</ul>
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
<i class="fa fa-search"></i>
</button>
</div>
<h1 class="menu-title">Synapse</h1>
<div class="right-buttons">
<a href="print.html" title="Print this book" aria-label="Print this book">
<i id="print-button" class="fa fa-print"></i>
</a>
<a href="https://github.com/matrix-org/synapse" title="Git repository" aria-label="Git repository">
<i id="git-repository-button" class="fa fa-github"></i>
</a>
<a href="https://github.com/matrix-org/synapse/edit/develop/docs/opentracing.md" title="Suggest an edit" aria-label="Suggest an edit">
<i id="git-edit-button" class="fa fa-edit"></i>
</a>
</div>
</div>
<div id="search-wrapper" class="hidden">
<form id="searchbar-outer" class="searchbar-outer">
<input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
</form>
<div id="searchresults-outer" class="searchresults-outer hidden">
<div id="searchresults-header" class="searchresults-header"></div>
<ul id="searchresults">
</ul>
</div>
</div>
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
<script type="text/javascript">
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
});
</script>
<div id="content" class="content">
<main>
<!-- Page table of contents -->
<div class="sidetoc">
<nav class="pagetoc"></nav>
</div>
<h1 id="opentracing"><a class="header" href="#opentracing">OpenTracing</a></h1>
<h2 id="background"><a class="header" href="#background">Background</a></h2>
<p>OpenTracing is a semi-standard being adopted by a number of distributed
tracing platforms. It is a common api for facilitating vendor-agnostic
tracing instrumentation. That is, we can use the OpenTracing api and
select one of a number of tracer implementations to do the heavy lifting
in the background. Our current selected implementation is Jaeger.</p>
<p>OpenTracing is a tool which gives an insight into the causal
relationship of work done in and between servers. The servers each track
events and report them to a centralised server - in Synapse's case:
Jaeger. The basic unit used to represent events is the span. The span
roughly represents a single piece of work that was done and the time at
which it occurred. A span can have child spans, meaning that the work of
the child had to be completed for the parent span to complete, or it can
have follow-on spans which represent work that is undertaken as a result
of the parent but is not depended on by the parent to in order to
finish.</p>
<p>Since this is undertaken in a distributed environment a request to
another server, such as an RPC or a simple GET, can be considered a span
(a unit or work) for the local server. This causal link is what
OpenTracing aims to capture and visualise. In order to do this metadata
about the local server's span, i.e the 'span context', needs to be
included with the request to the remote.</p>
<p>It is up to the remote server to decide what it does with the spans it
creates. This is called the sampling policy and it can be configured
through Jaeger's settings.</p>
<p>For OpenTracing concepts see
<a href="https://opentracing.io/docs/overview/what-is-tracing/">https://opentracing.io/docs/overview/what-is-tracing/</a>.</p>
<p>For more information about Jaeger's implementation see
<a href="https://www.jaegertracing.io/docs/">https://www.jaegertracing.io/docs/</a></p>
<h2 id="setting-up-opentracing"><a class="header" href="#setting-up-opentracing">Setting up OpenTracing</a></h2>
<p>To receive OpenTracing spans, start up a Jaeger server. This can be done
using docker like so:</p>
<pre><code class="language-sh">docker run -d --name jaeger \
-p 6831:6831/udp \
-p 6832:6832/udp \
-p 5778:5778 \
-p 16686:16686 \
-p 14268:14268 \
jaegertracing/all-in-one:1
</code></pre>
<p>Latest documentation is probably at
https://www.jaegertracing.io/docs/latest/getting-started.</p>
<h2 id="enable-opentracing-in-synapse"><a class="header" href="#enable-opentracing-in-synapse">Enable OpenTracing in Synapse</a></h2>
<p>OpenTracing is not enabled by default. It must be enabled in the
homeserver config by uncommenting the config options under <code>opentracing</code>
as shown in the <a href="./sample_config.yaml">sample config</a>. For example:</p>
<pre><code class="language-yaml">opentracing:
enabled: true
homeserver_whitelist:
- "mytrustedhomeserver.org"
- "*.myotherhomeservers.com"
</code></pre>
<h2 id="homeserver-whitelisting"><a class="header" href="#homeserver-whitelisting">Homeserver whitelisting</a></h2>
<p>The homeserver whitelist is configured using regular expressions. A list
of regular expressions can be given and their union will be compared
when propagating any spans contexts to another homeserver.</p>
<p>Though it's mostly safe to send and receive span contexts to and from
untrusted users since span contexts are usually opaque ids it can lead
to two problems, namely:</p>
<ul>
<li>If the span context is marked as sampled by the sending homeserver
the receiver will sample it. Therefore two homeservers with wildly
different sampling policies could incur higher sampling counts than
intended.</li>
<li>Sending servers can attach arbitrary data to spans, known as
'baggage'. For safety this has been disabled in Synapse but that
doesn't prevent another server sending you baggage which will be
logged to OpenTracing's logs.</li>
</ul>
<h2 id="configuring-jaeger"><a class="header" href="#configuring-jaeger">Configuring Jaeger</a></h2>
<p>Sampling strategies can be set as in this document:
<a href="https://www.jaegertracing.io/docs/latest/sampling/">https://www.jaegertracing.io/docs/latest/sampling/</a>.</p>
</main>
<nav class="nav-wrapper" aria-label="Page navigation">
<!-- Mobile navigation buttons -->
<a rel="prev" href="dev/git.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
<i class="fa fa-angle-left"></i>
</a>
<a rel="next" href="development/database_schema.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
<i class="fa fa-angle-right"></i>
</a>
<div style="clear: both"></div>
</nav>
</div>
</div>
<nav class="nav-wide-wrapper" aria-label="Page navigation">
<a rel="prev" href="dev/git.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
<i class="fa fa-angle-left"></i>
</a>
<a rel="next" href="development/database_schema.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
<i class="fa fa-angle-right"></i>
</a>
</nav>
</div>
<script type="text/javascript">
window.playground_copyable = true;
</script>
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
<script src="mark.min.js" type="text/javascript" charset="utf-8"></script>
<script src="searcher.js" type="text/javascript" charset="utf-8"></script>
<script src="clipboard.min.js" type="text/javascript" charset="utf-8"></script>
<script src="highlight.js" type="text/javascript" charset="utf-8"></script>
<script src="book.js" type="text/javascript" charset="utf-8"></script>
<!-- Custom JS scripts -->
<script type="text/javascript" src="docs/website_files/table-of-contents.js"></script>
</body>
</html>
|
