[tahoe-dev] Logging howto / sftp with hashed passwords

Wolfgang Strobl news4 at mystrobl.de
Thu Mar 22 10:15:14 UTC 2012

Hi folks, I'm new to this list and mostly new to tahoe. Alas, my first attempt of posting using the gmane gateway failed, so I try again by mail.

I've sucessfully installed tahoe and created/used two small grids on a few machines (OpenSuse Linux 11.4, Win XP, Win7/64). Currently I try to understand some of the internals, but in vain. The current stopgap is my inability to get some kind of logging or debugging output working.  My first step in learning about the innards of some new software is usually done by sprinkling a few print statements and/or "import pdb;pdb.set_trace()" over the interesting parts and looking at the output.

Both logfiles in node/logs are quite short, there is no "verbose" flag anywhere, Python logging isn't used, stdout goes nowhere, running a node (../bin/tahoe run testgrid/client) doesn't produce any output, even in foreground.

After reading through the wiki and some other material found via google I finally found "flogtool" in support/bin, but couldn't get it working. Do I really have to install easy_install/setuptools globally, just in order to view some logfiles? I'd rather not touch my system Python, if that isn't really necessary.

I've tried to do a local tahoe lafs  installation using virtualenv before (on Windows), but that failed miserably.

A short writeup of the do's and don'ts of tahoe development for newcomers would be really great and welcome.

Finally, the real question I was researching before getting distracted was how to add hashed passwords to the sftp client. For security reasons, I don't like storing passwords as cleartext, not even for debugging purposes. Using hashes from apaches htpasswd and adding a crypt.crypt call in auth.py can't be that difficult, I thought. Boy, was I wrong! After reading through auth.py, I got the vague impression that hashed passwords already are supported, but I just don't see the mechanism at work, in that code, and fail to see where to look further. It seems that it is using twisted infrastructure (which I don't know anything about), but where and how?

Sorry about sounding somewhat negative. Tahoe LAFS represents an impressive work and could serve an urgent need (a base for a secure, private cloud based on OSS components), but the learning curve is steep, when it comes to customizing and/or developing small modifications. Any suggestions where to look or what to read?


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