Due to how deeply the configuration types go into Terraform Core, there
isn't a great way to switch out to HCL2 gradually. As a consequence, this
huge commit gets us from the old state to a _compilable_ new state, but
does not yet attempt to fix any tests and has a number of known missing
parts and bugs. We will continue to iterate on this in forthcoming
commits, heading back towards passing tests and making Terraform
fully-functional again.
The three main goals here are:
- Use the configuration models from the "configs" package instead of the
older models in the "config" package, which is now deprecated and
preserved only to help us write our migration tool.
- Do expression inspection and evaluation using the functionality of the
new "lang" package, instead of the Interpolator type and related
functionality in the main "terraform" package.
- Represent addresses of various objects using types in the addrs package,
rather than hand-constructed strings. This is not critical to support
the above, but was a big help during the implementation of these other
points since it made it much more explicit what kind of address is
expected in each context.
Since our new packages are built to accommodate some future planned
features that are not yet implemented (e.g. the "for_each" argument on
resources, "count"/"for_each" on modules), and since there's still a fair
amount of functionality still using old-style APIs, there is a moderate
amount of shimming here to connect new assumptions with old, hopefully in
a way that makes it easier to find and eliminate these shims later.
I apologize in advance to the person who inevitably just found this huge
commit while spelunking through the commit history.
During a full destroy when outputs are removed, the
NodeDestroyableOutput was preventing it's sibling output from being
destroyed. Prune the output node if it only has its destroy node as a
dependent.
The destroy output test is simply run a second time with no state, which
would cause the output interpolation to fail if it remained in the
graph.
Since outputs and local nodes are always evaluated, if the reference a
resource form the configuration that isn't in the state, the
interpolation could fail.
Prune any local or output values that have no references in the graph.
Now that outputs are always evaluated, we still need a way to remove
them from state when they are destroyed.
Previously, outputs were removed during destroy from the same
"Applyable" node type that evaluates them. Now that we need to possibly
both evaluate and remove output during an apply, we add a new node -
NodeDestroyableOutput.
This new node is added to the graph by the DestroyOutputTransformer,
which make the new destroy node depend on all descendants of the output
node. This ensures that the output remains in the state as long as
everything which may interpolate the output still exists.
Always evaluate outputs during destroy, just like we did for locals.
This breaks existing tests, which we will handle separately.
Don't reverse output/local node evaluation order during destroy, as they
are both being evaluated.
Destroy-time provisioners require us to re-evaluate during destroy.
Rather than destroying local values, which doesn't do much since they
aren't persisted to state, we always evaluate them regardless of the
type of apply. Since the destroy-time local node is no longer a
"destroy" operation, the order of evaluation need to be reversed. Take
the existing DestroyValueReferenceTransformer and change it to reverse
the outgoing edges, rather than in incoming edges. This makes it so that
any dependencies of a local or output node are destroyed after
evaluation.
Having locals evaluated during destroy failed one other test, but that
was the odd case where we need `id` to exist as an attribute as well as
a field.
There was a bug where all references would be discarded in the case when
a self-reference was encountered. Since a module references all
descendants by it's own path, it returns a self-reference by definition.
This turned out to be a big messy commit, since the way providers are
referenced is tightly coupled throughout the code. That starts to unify
how providers are referenced, using the format output node Name method.
Add a new field to the internal resource data types called
ResolvedProvider. This is set by a new setter method SetProvider when a
resource is connected to a provider during graph creation. This allows
us to later lookup the provider instance a resource is connected to,
without requiring it to have the same module path.
The InitProvider context method now takes 2 arguments, one if the
provider type and the second is the full name of the provider. While the
provider type could still be parsed from the full name, this makes it
more explicit and, and changes to the name format won't effect this
code.
DestroyValueReferenceTransformer is used during destroy to reverse the
edges for output and local values. Because destruction is going to
remove these from the state, nodes that depend on their value need to be
visited first.
A local value is similar to an output in that it exists only within state
and just always evaluates its value as best it can with the current state.
Therefore it has a single graph node type for all walks, which will
deal with that evaluation operation.
terraform: more specific resource references
terraform: outputs need to know about the new reference format
terraform: resources w/o a config still have a referencable name
