1VMOD(VTC) VMOD(VTC)
2
6 VMOD vtc - Utility module for varnishtest
7
9 import vtc [as name] [from "path"]
10 VOID barrier_sync(STRING addr, DURATION timeout)
12 BACKEND no_backend()
14 STEVEDORE no_stevedore()
16 IP no_ip()
18 VOID panic(STRING)
20 VOID sleep(DURATION)
22 VOID workspace_alloc(ENUM, INT size)
24 INT workspace_free(ENUM)
26 VOID workspace_snapshot(ENUM)
28 VOID workspace_reset(ENUM)
30 BOOL workspace_overflowed(ENUM)
32 VOID workspace_overflow(ENUM)
34 BLOB workspace_dump(ENUM, ENUM, BYTES off, BYTES len)
36 INT typesize(STRING)
38
40 The goal for this VMOD is to provide VCL users and VMOD authors means
41 to test corner cases or reach certain conditions with varnishtest.
42 VOID barrier_sync(STRING addr, DURATION timeout=0)
44 When writing test cases, the most common pattern is to start a mock
45 server instance, a Varnish instance, and spin up a mock client. Those
46 entities run asynchronously, and others exist like background processes
47 (process) or log readers (logexpect). While you can synchronize with
48 individual entities and wait for their completion, you must use a bar‐
49 rier if you need to synchronize two or more entities, or wait until a
50 certain point instead of completion.
51 Not only is it possible to synchronize between test entities, with the
53 barrier_sync function you can even synchronize VCL code:
54 sub vcl_recv {
56 # wait for some barrier b1 to complete
57 vtc.barrier_sync("${b1_sock}");
58 }
59 If the function fails to synchronize with the barrier for some reason,
61 or if it reaches the optional timeout, it fails the VCL transaction.
62
64 BACKEND no_backend()
65 Fails at backend selection.
66 STEVEDORE no_stevedore()
68 Fails at storage selection.
69 IP no_ip()
71 Returns a null IP address, not even a bogo_ip.
72 VOID panic(STRING)
74 It can be useful to crash the child process in order to test the
75 robustness of a VMOD.
76 VOID sleep(DURATION)
78 Block the current worker thread.
79
81 It can be useful to put a workspace in a given state when testing cor‐
82 ner cases like resource exhaustion for a transaction, especially for
83 VMOD development. All functions available allow to pick which workspace
84 you need to tamper with, available values are client, backend, session
85 and thread.
86 VOID workspace_alloc(ENUM, INT size)
88 VOID workspace_alloc(
89 ENUM {client, backend, session, thread},
90 INT size
91 )
92 Allocate and zero out memory from a workspace. A negative size will
94 allocate as much as needed to leave that many bytes free. The actual
95 allocation size may be higher to comply with memory alignment require‐
96 ments of the CPU architecture. A failed allocation fails the transac‐
97 tion.
98 INT workspace_free(ENUM {client, backend, session, thread})
100 Find how much unallocated space there is left in a workspace.
101 VOID workspace_snapshot(ENUM)
103 VOID workspace_snapshot(ENUM {client, backend, session, thread})
104 Snapshot a workspace. Only one snapshot may be active at a time and
106 each VCL can save only one snapshot, so concurrent tasks requiring
107 snapshots are not supported.
108 VOID workspace_reset(ENUM)
110 VOID workspace_reset(ENUM {client, backend, session, thread})
111 Reset to the previous snapshot of a workspace, it must be the same
113 workspace too.
114 BOOL workspace_overflowed(ENUM)
116 BOOL workspace_overflowed(ENUM {client, backend, session, thread})
117 Find whether the workspace overflow mark is set or not.
119 VOID workspace_overflow(ENUM)
121 VOID workspace_overflow(ENUM {client, backend, session, thread})
122 Mark a workspace as overflowed.
124 BLOB workspace_dump(ENUM, ENUM, BYTES off, BYTES len)
126 BLOB workspace_dump(
127 ENUM {client, backend, session, thread},
128 ENUM {s, f, r},
129 BYTES off=0,
130 BYTES len=64
131 )
132 Return data from a workspace's s, f, or r pointer as a blob. Data is
134 copied onto the primary workspace to avoid it being subsequently over‐
135 written.
136 The maximum len is 1KB.
138 INT typesize(STRING)
140 Returns the size in bytes of a collection of C-datatypes:
141 · 'p': pointer
143 · 'i': int
145 · 'd': double
147 · 'f': float
149 · 'l': long
151 · 's': short
153 · 'z': size_t
155 · 'o': off_t
157 · 'j': intmax_t
159 This can be useful for VMOD authors in conjunction with workspace oper‐
161 ations.
162
164 · vtc(7)
165 · vcl(7)
167
169 Copyright (c) 2017 Varnish Software AS
170 All rights reserved.
171 Author: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>
173 Redistribution and use in source and binary forms, with or without
175 modification, are permitted provided that the following conditions
176 are met:
177 1. Redistributions of source code must retain the above copyright
178 notice, this list of conditions and the following disclaimer.
179 2. Redistributions in binary form must reproduce the above copyright
180 notice, this list of conditions and the following disclaimer in the
181 documentation and/or other materials provided with the distribution.
182 THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
184 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
185 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
186 ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
187 FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
188 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
189 OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
190 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
191 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
192 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
193 SUCH DAMAGE.
194 3 VMOD(VTC)