provider/template: fix race causing panic in template_file #4694
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The render code path in
template_file
was doing unsynchronized accessto a shared mapping of functions in
config.Func
.This caused a race condition that was most often triggered when a
template_file
had acount
of more than one, and expressed itself asa panic in the plugin followed by a cascade of "unexpected EOF" errors
through the plugin system.
Here, we simply turn the FuncMap from shared state into a generated
value, which avoids the race. We do more re-initialization of the data
structure, but the performance implications are minimal, and we can
always revisit with a perf pass later now that the race is fixed.