nixops script: Remove top-level Exception catch-all. #924
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Having this catch-all made it difficult to develop and troubleshoot
nixops.
For example, when adding a new backend and forgetting to add the
corresponding `option` in the `.nix` file, nixops would die simply
with
error: 'serverType'
which is not a good indication over what went wrong.
Specifically so because `error(str(e))` removed the type of the
exception, turning `KeyError: 'serverType'` into just `serverType`.
So far, you could pass `--show-trace` or `--debug` to see
Python stack traces.
However, that requires the error to be easily reproducible
(when you see it, you have to run again with `--show-trace`),
making debugging of rare problems hard.
For an ops tool we should make debugging of rare/unknown
problems as easy as possible.
Consequently, this commit makes Python raise the `Exception`
with stack trace if we have no idea at all what the exception
type is.
The other cases (when we know what exception type it is)
remain unaffected.
|
Related: #710 (basically makes what was asked there the default for those exceptions that are very likely programmer errors / nixops bugs or bugs in nixops dependencies) |
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Below is a small patch to fix one of my biggest gripes in using and developing nixops, and in helping colleagues and friends fix their problems.
Having this catch-all made it difficult to develop and troubleshoot
nixops.
For example, when adding a new backend and forgetting to add the
corresponding
optionin the.nixfile, nixops would die simplywith
which is not a good indication over what went wrong.
Specifically so because
error(str(e))removed the type of theexception, turning
KeyError: 'serverType'into justserverType.So far, you could pass
--show-traceor--debugto seePython stack traces.
However, that requires the error to be easily reproducible
(when you see it, you have to run again with
--show-trace),making debugging of rare problems hard.
For an ops tool we should make debugging of rare/unknown
problems as easy as possible.
Consequently, this commit makes Python raise the
Exceptionwith stack trace if we have no idea at all what the exception
type is.
The other cases (when we know what exception type it is)
remain unaffected.