Use exact IPv4/IPv6 address in test_run:cmd() #197
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When test-run's inspector listens on a IPv4 port and some other process listens on a IPv6 port of the same number, test_run:cmd() could connect to this process rather then the inspector, because 'localhost' hostname was used to connect. Now test-run passes actual IP address of the inspector via an environment variable and test_run:cmd() uses it to avoid the ambiguity that is described above. The problem was found during many parallel runs of app/socket.test.lua test from tarantool, see case 4 in [1] (untitled, see right under case 3). This test starts many TCP servers and in rare cases a server port may be the same as inspector's one. There are two details that increase probability of the problem: * It seems test-run's inspector always listens on IPv4 address, because it is configured with 'localhost' hostname and gevent.server.StreamServer implementation always chooses IPv4 for 'localhost' (see [2], _parse_address() function). * socket.tcp_connect() typically tries to connect to an IPv6 address first and only then to an IPv4 one, because getaddrinfo() returns addresses in this order according to RFC 3484 (see [3], section 2.1 'Policy table'). This however can be configured in /etc/gai.conf. [1]: https://lists.tarantool.org/pipermail/tarantool-patches/2019-December/013321.html [2]: https://github.com/gevent/gevent/blob/ba3b15de7eb568fa09fdf1a9d28241288163ba67/src/gevent/baseserver.py#L406-L409 [3]: https://tools.ietf.org/rfc/rfc3484.txt
avtikhon
approved these changes
Dec 26, 2019
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When test-run's inspector listens on a IPv4 port and some other process
listens on a IPv6 port of the same number, test_run:cmd() could connect
to this process rather then the inspector, because 'localhost' hostname
was used to connect.
Now test-run passes actual IP address of the inspector via an
environment variable and test_run:cmd() uses it to avoid the ambiguity
that is described above.
The problem was found during many parallel runs of app/socket.test.lua
test from tarantool, see case 4 in 1 (untitled, see right under case
3). This test starts many TCP servers and in rare cases a server port
may be the same as inspector's one.
There are two details that increase probability of the problem:
It seems test-run's inspector always listens on IPv4 address, because
it is configured with 'localhost' hostname and
gevent.server.StreamServer implementation always chooses IPv4 for
'localhost' (see 2, _parse_address() function).
socket.tcp_connect() typically tries to connect to an IPv6 address
first and only then to an IPv4 one, because getaddrinfo() returns
addresses in this order according to RFC 3484 (see 3, section 2.1
'Policy table'). This however can be configured in /etc/gai.conf.