Fix NVMe device path detection #41
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Under linux (under the persistent naming rules present in most distributions AFAIK), the NVMe device by-id symlinks point to the block device (e.g., `/dev/nvme0n1`) rather than the controller (`/dev/nvme0`) as assumed by original code. This change fixes the NVMe device parsing, but rather than inelegantly trying to twiddle the string (where in principle the "namespace" portion might be more than the 2 characters "n1"), we query the udev database directly, and find the parent device's sysfs path. Unfortunately, the test file `test_00_data.py` (which contained the same symlink naming bug) doesn't have a simple fix, so someone will have to patch it more deeply. Another disadvantage is, of course, that we're adding a new dependency on pyudev, which can be another point of failure. On the other hand, pyudev might ultimately be the way forward, and a deeper refactor might clean up some of the uglier sysfs path munging. It may also make it easier to solve AMD autodetection.
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If pyudev is not desired as a dependency, then of course the string parsing could work if you assume a two-character namespace (it's probably "n1" in 99% of cases). |
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Closing this PR. Please see updated #42. |
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Under linux (under the persistent naming rules present in most distributions AFAIK), the NVMe device by-id symlinks point to the block device (e.g.,
/dev/nvme0n1) rather than the controller (/dev/nvme0) as assumed by original code.This change fixes the NVMe device parsing, but rather than inelegantly trying to twiddle the string (where in principle the "namespace" portion might be more than the 2 characters "n1"), we query the udev database directly, and find the parent device's sysfs path.
Unfortunately, the test file
test_00_data.py(which contained the same symlink naming bug) doesn't have a simple fix, so someone will have to patch it more deeply. Another disadvantage is, of course, that we're adding a new dependency on pyudev, which can be another point of failure.On the other hand, pyudev might ultimately be the way forward, and a deeper refactor might clean up some of the uglier sysfs path munging. It may also make it easier to solve AMD autodetection.