This commit follows up on 2e71db2 (dockcross: Ignore deletion error
when running in unprivileged LXC container) by hiding the message
only when (a) the command output matches the expected error message
and (b) is executed on CircleCI.
Doing so will avoid adding "noise" to log of service like CircleCI
that are effectively running docker in unprivileged LXC container.
See #50
This commit removes the complex pipeline leveraging output from
/dev/urandom and simply uses $RANDOM variable. For the purpose
of generating an available container name, it will works well.
Suggested-by: Matt McCormick <matt.mccormick@kitware.com>
As explained in [1], when using dockcross from python subprocess, the
interactive mode is disabled and output of "cat /dev/urandom" is block
buffered instead of being line buffered.
Workaround to this problem is to simply read a fixed amount of characters
from urandom.
The following two snippets illustrates the problem and the
the implemented solution:
Works
```python
import subprocess as sp
sp.check_call("var=$(head -c 500 /dev/urandom | base64 | tr -dc 'a-zA-Z0-9' | fold -w 7 | head -n 1); echo $var", shell=True)
```
=> output random string
Fail:
```python
import subprocess as sp
sp.check_call("var=$(cat /dev/urandom | base64 | tr -dc 'a-zA-Z0-9' | fold -w 7 | head -n 1); echo $var", shell=True)
```
=> Hang
[1] http://stackoverflow.com/questions/16805827/unable-to-read-stdout-from-a-running-process#16806506
where RAND is a 7 characters long randomly generated alphanumeric string.
Note that container name can NOT start with "_",
only [a-zA-Z0-9][a-zA-Z0-9_.-] are allowed
See #50
