Simplify the use of clistate.Lock by creating a clistate.Locker
instance, which stores the context of locking a state, to allow unlock
to be called without knowledge of how the state was locked.
This alows the backend code to bring the needed UI methods to the point
where the state is locked, and still unlock the state from an outer
scope.
Provide a NoopLocker as well, so that callers can always call Unlock
without verifying the status of the lock.
Add the StateLocker field to the backend.Operation, so that the state
lock can be carried between the different function scopes of the backend
code. This will allow the backend context to lock the state before it's
read, while allowing the different operations to unlock the state when
they complete.
Moves the nested select statements for backend operations into a single
function. The only difference in this part was that apply called
PersistState, which should be harmless regardless of the type of
operation being run.
If the user wishes to interrupt the running operation, only the first
interrupt was communicated to the operation by canceling the provided
context. A second interrupt would start the shutdown process, but not
communicate this to the running operation. This order of event could
cause partial writes of state.
What would happen is that once the command returns, the plugin system
would stop the provider processes. Once the provider processes dies, all
pending Eval operations would return return with an error, and quickly
cause the operation to complete. Since the backend code didn't know that
the process was shutting down imminently, it would continue by
attempting to write out the last known state. Under the right
conditions, the process would exit part way through the writing of the
state file.
Add Stop and Cancel CancelFuncs to the RunningOperation, to allow it to
easily differentiate between the two signals. The backend will then be
able to detect a shutdown and abort more gracefully.
In order to ensure that the backend is not in the process of writing the
state out, the command will always attempt to wait for the process to
complete after cancellation.
Add fields required to create an appropriate context for all calls to
clistate.Lock.
Add missing checks for Meta.stateLock, where we would attempt to lock,
even if locking should be skipped.
- Have the ui Lock helper use state.LockWithContext.
- Rename the message package to clistate, since that's how it's imported
everywhere.
- Use a more idiomatic placement of the Context in the LockWithContext
args.
This allows a refresh on a non-existent or empty state file. We changed
this in 0.9.0 to error which seemed reasonable but it turns out this
complicates automation that runs refresh since it now needed to
determine if the state file was empty before running.
Its easier to just revert this into a warning with exit code zero.
The reason this changed is because in 0.8.x and earlier, the output
would be simply empty with exit code zero which seemed odd.
Fixes#12174
You're allowed to refresh with a nil module (no configs) as long as you
have state. However, if `-input=true` (default) then this would crash
since the input attempts to read the configs.
The API contract with `terraform.Context` says that the module tree must
be non-nil and loaded. To do this for other commands we create an empty
module tree. We do that here now.
The local backend implementation is an implementation of
backend.Enhanced that recreates all the behavior of the CLI but through
the backend interface.
James Bardin