This change deflakes TestTaskTemplateManager_BlockedEvents test, because
it is expecting a number of events without accounting for transitional
state.
The test TestTaskTemplateManager_BlockedEvents attempts to ensure that a
template rendering emits blocked events for missing template ksys.
It works by setting a template that requires keys 0,1,2,3,4 and then
eventually sets keys 0,1,2,3 and ensures that we get a final event indicating
that keys 3 and 4 are still missing.
The test waits to get a blocked event for the final state, but it can
fail if receives a blocked event for a transitional state (e.g. one
reporting 2,3,4,5 are missing).
This fixes the test by ensuring that it waits until the final message
before assertion.
Also, it clarifies the intent of the test with stricter assertions and
additional comments.
When rendering a task template, the `plugin` function is no longer
permitted by default and will raise an error. An operator can opt-in
to permitting this function with the new `template.function_blacklist`
field in the client configuration.
When rendering a task template, path parameters for the `file`
function will be treated as relative to the task directory by
default. Relative paths or symlinks that point outside the task
directory will raise an error. An operator can opt-out of this
protection with the new `template.disable_file_sandbox` field in the
client configuration.
When rendering a task consul template, ensure that only task environment
variables are used.
Currently, `consul-template` always falls back to host process
environment variables when key isn't a task env var[1]. Thus, we add
an empty entry for each host process env-var not found in task env-vars.
[1] bfa5d0e133/template/funcs.go (L61-L75)
As part of deprecating legacy drivers, we're moving the env package to a
new drivers/shared tree, as it is used by the modern docker and rkt
driver packages, and is useful for 3rd party plugins.
