Blackhole¶
.o8 oooo oooo oooo oooo o8o
"888 `888 `888 `888 `888 `"'
888oooo. 888 .oooo. .ooooo. 888 oooo 888 .oo. .ooooo. 888 .ooooo. oooo .ooooo.
d88' `88b 888 `P )88b d88' `"Y8 888 .8P' 888P"Y88b d88' `88b 888 d88' `88b `888 d88' `88b
888 888 888 .oP"888 888 888888. 888 888 888 888 888 888ooo888 888 888 888
888 888 888 d8( 888 888 .o8 888 `88b. 888 888 888 888 888 888 .o .o. 888 888 888
`Y8bod8P' o888o `Y888""8o `Y8bod8P' o888o o888o o888o o888o `Y8bod8P' o888o `Y8bod8P' Y8P o888o `Y8bod8P'
Blackhole is a Tornado powered MTA (mail transport agent) that is designed for handling large volumes of email without handling any of the messages and doing no disk bound I/O.
Blackhole is designed mostly for testing purposes and can be used to test numerous things suchs as;
- Email send rates, if you need to test how much mail you can send per minute, hour etc
- Email integration testing and finally
- if you work in the real world, chances are you’ll need work on a copy of production data from time to time. You can try to anonymous all the data but there is always a chance you’ll miss something. Configuring blackhole as your applications default SMTP gateway will remove any chance of a real person receiving an email they shouldn’t have received.
Using the blackhole.io service¶
All data sent to blackhole.io will be forgotten instantly, we store nothing you send.
- Point your application’s outgoing SMTP server to ‘blackhole.io’,
- Sit back and watch mail never get delivered to a real user.
or, send an email to blackhole.io using an @blackhole.io address, any address is fine e.g.:
user1@blackhole.io
Testing via telnet¶
$ telnet blackhole 25
Trying 198.199.126.159...
Connected to blackhole.io.
Escape character is '^]'.
220 2.2.0 OK, ready
HELO fake.mail.server
250 2.5.0 OK, done
MAIL FROM:<user@address.tld>
250 2.5.0 OK, done
RCPT TO:<someone@another.tld>
250 2.5.0 OK, done
DATA
354 3.5.4 Start mail input; end with <CRLF>.<CRLF>
To: Someone <someone@another.tld>
From: User <user@address.tld>
Subject: Bye
Bye bye email
.
251 2.5.1 OK, user not local, will forward
QUIT
221 2.2.1 Thank you for speaking to me
Connection closed by foreign host.
Testing SSL¶
$ openssl s_client -connect blackhole.io:465
CONNECTED(00000003)
depth=0 C = GB, ST = London, L = London, O = blackhole.io, OU = blackhole.io, CN = blackhole.io, emailAddress = kura@blackhole.io
... snip ...
---
220 2.2.0 OK, ready
HELO fake.mail.server
250 2.5.0 OK, done
MAIL FROM:<user@address.tld>
250 2.5.0 OK, done
RCPT TO:<someone@another.tld>
250 2.5.0 OK, done
DATA
354 3.5.4 Start mail input; end with <CRLF>.<CRLF>
To: Someone <someone@another.tld>
From: User <user@address.tld>
Subject: Bye
Bye bye email
.
251 2.5.1 OK, user not local, will forward
QUIT
221 2.2.1 Thank you for speaking to me
DONE
Getting the source code¶
The source code is available under the MIT license from GitHub.
Running your own server¶
Python versions¶
Python 2.6
Python 2.7
Python 3.2
Python 3.3
PyPy 1.9 # see notes below
PyPy 2.0 # see notes below
Blackhole works on Python 2.6 and 2.7, it also works with PyPy (see Blackhole + PyPy section below).
Third party libraries¶
tornado>=2.2.1,<=3.1
setproctitle>=1.1.6 # setproctitle 1.1.7 and above are required for all PyPy versions
deiman>=0.1.4 # older version of Deiman will not work because of API changes
Tests & Coverage¶
Running tests manually¶
Running tests manually is pretty simple, there is a Make target dedicated to it.
The test suite relies on unittest2 and nose, both if which get installed by the Make target during test running.
make tests
There is also a Make target for generating coverage:
make coverage
Blackhole + PyPy¶
PyPy is a Python interpreter and just-in-time compiler. PyPy focuses on speed, efficiency and compatibility with the original CPython interpreter.
Blackhole works well under PyPy 1.9, 2.0 beta1 and 2.0 beta2, you can see performance improvements of up to 30% in certain situations.
However, blackhole does have issues with both PyPy 1.9 and 2.0 beta1 and 2.0 beta2 when using the pre-compiled binaries, this is due to a conflict in the version of OpenSSL compiled in to PyPy and the version compiled in to your CPython installation. If you wish to use blackhole with SSL support on PyPy I suggest you either compile PyPy yourself or try to make sure your PyPy and CPython have the same versions.
FAQ¶
A few people have emailed me questions about why blackhole exists, how I use it, why Tornado and things like that so I have outlined some questions and responses in an FAQ.