Obnam not working well

For me at least. Looking at different backup solutions I have been evaluating Obnam, a python based backup application. Using Obnam v 1.15 on Ubuntu 15.10 on a laptop, backing up to a server over the network. I have now also tried version 1.19.1, same problem

Today, looking at the logs I noticed it is stuck in a loop

2016-02-19 13:19:25 INFO Locking client client1
2016-02-19 13:19:25 CRITICAL Node 0x1026 cannot be found in the node store chunksums: 2: No such file: None
Traceback (most recent call last):

It does not seem to recover from this looping. I am running obnam through a python script under Supervisord that uses subprocess to start obnam every two hours or so. Before each invocation I do a "force-lock" to get rid of any hanging locks (possibly from interrupted backup sessions, it's a laptop). There is some help here: Missing node or KeyError problems on the obnam web site, but I used more recent versions of obnam, namely 1.15 and 1.19.1.

Furthermore, yesterday I noticed obnam hanging on certain patterns in the config file. Specifically, it doesn't like patterns of this form:

exclude = /node_modules/

It will just hang when it encounters this pattern in the file system. I have not verified this extensively but it seems to hang when there is a trailing slash. This mitigated the problem:

exclude = /node_modules$, /node_modules/

I.e. first match the directory and then any underlying files.