While removal of attributes can be handled by providers through the
UpgradeResourceState call, data sources may need to be evaluated before
reading, and they have no upgrade path in the provider protocol.
Strip out extra attributes during state decoding when they are no longer
present in the schema, and there is no schema upgrade pending.
* terraform: large refactor to use Provider from configs.Resource
configs.Resource.ImpliedProvider() now returns a string; it is the
callers' responsibility to turn that into an addrs.Provider if needed.
GraphNodeProviderConsumer ProvidedBy() no longer returns nil (reverting
to earlier, pre-provider-fqn behavior): it will return either the
provider set in config, provider set in state, or the default provider.
* Introduce "Local" terminology for non-absolute provider config addresses
In a future change AbsProviderConfig and LocalProviderConfig are going to
become two entirely distinct types, rather than Abs embedding Local as
written here. This naming change is in preparation for that subsequent
work, which will also include introducing a new "ProviderConfig" type
that is an interface that AbsProviderConfig and LocalProviderConfig both
implement.
This is intended to be largely just a naming change to get started, so
we can deal with all of the messy renaming. However, this did also require
a slight change in modeling where the Resource.DefaultProviderConfig
method has become Resource.DefaultProvider returning a Provider address
directly, because this method doesn't have enough information to construct
a true and accurate LocalProviderConfig -- it would need to refer to the
configuration to know what this module is calling the provider it has
selected.
In order to leave a trail to follow for subsequent work, all of the
changes here are intended to ensure that remaining work will become
obvious via compile-time errors when all of the following changes happen:
- The concept of "legacy" provider addresses is removed from the addrs
package, including removing addrs.NewLegacyProvider and
addrs.Provider.LegacyString.
- addrs.AbsProviderConfig stops having addrs.LocalProviderConfig embedded
in it and has an addrs.Provider and a string alias directly instead.
- The provider-schema-handling parts of Terraform core are updated to
work with addrs.Provider to identify providers, rather than legacy
strings.
In particular, there are still several codepaths here making legacy
provider address assumptions (in order to limit the scope of this change)
but I've made sure each one is doing something that relies on at least
one of the above changes not having been made yet.
* addrs: ProviderConfig interface
In a (very) few special situations in the main "terraform" package we need
to make runtime decisions about whether a provider config is absolute
or local.
We currently do that by exploiting the fact that AbsProviderConfig has
LocalProviderConfig nested inside of it and so in the local case we can
just ignore the wrapping AbsProviderConfig and use the embedded value.
In a future change we'll be moving away from that embedding and making
these two types distinct in order to represent that mapping between them
requires consulting a lookup table in the configuration, and so here we
introduce a new interface type ProviderConfig that can represent either
AbsProviderConfig or LocalProviderConfig decided dynamically at runtime.
This also includes the Config.ResolveAbsProviderAddr method that will
eventually be responsible for that local-to-absolute translation, so
that callers with access to the configuration can normalize to an
addrs.AbsProviderConfig given a non-nil addrs.ProviderConfig. That's
currently unused because existing callers are still relying on the
simplistic structural transform, but we'll switch them over in a later
commit.
* rename LocalType to LocalName
Co-authored-by: Kristin Laemmert <mildwonkey@users.noreply.github.com>
Previously we tried to short-circuit this if the schema version hadn't
changed and we were already using JSON serialization. However, if we
instead call into UpgradeResourceState every time we can let the provider
or the SDK do some general, systematic normalization and cleanup steps
without always requiring a schema version increase.
What exactly would be fixed up this way is for the SDK to decide, but for
example the SDK might choose to automatically delete from the state
anything that is no longer present in the schema, avoiding the need to
write explicit state migration functions for that common case where the
remedy is always the same.
The actual update logic is delegated to the provider/SDK intentionally so
that it can evolve over time and potentially differ depending on how
each SDK thinks about schema.
When a resource type schema includes dynamically-typed attributes we can't
do any automatic conversion from flatmap to JSON because we don't know
how to interpret the keys that start with the dynamically-typed
attribute's prefix.
To work around that, we'll instead just ask the SDK to do a no-op upgrade
(current and target versions are the same) which will convert from flatmap
to JSON using the SDK's own logic as a side-effect.
This situation should rarely arise in real-world use, but it ends up being
very important for the helper/resource provider test harness because it
is forced to lower the state back to flatmap repeatedly after every step
in order to run legacy checking and processing code.
If an instance object in state has an earlier schema version number then
it is likely that the schema we're holding won't be able to decode the
raw data that is stored. Instead, we must ask the provider to upgrade it
for us first, which might also include translating it from flatmap form
if it was last updated with a Terraform version earlier than v0.12.
This ends up being a "seam" between our use of int64 for schema versions
in the providers package and uint64 everywhere else. We intend to
standardize on int64 everywhere eventually, but for now this remains
consistent with existing usage in each layer to keep the type conversion
noise contained here and avoid mass-updates to other Terraform components
at this time.
This also includes a minor change to the test helpers for the
backend/local package, which were inexplicably setting a SchemaVersion of
1 on the basic test state but setting the mock schema version to zero,
creating an invalid situation where the state would need to be downgraded.
