For this version of Terraform and forward, we no longer refuse to read
compatible state files written by future versions of Terraform. This is
a commitment that any changes to the semantics or format of the state
file after this commit will require a new state file version 5.
The result of this is that users of this Terraform version will be able
to share remote state with users of future versions, and all users will
be able to read and write state. This will be true until the next major
state file version is required.
This does not affect users of previous versions of Terraform, which will
continue to refuse to read state written by later versions.
* addrs: detect builtin provider when parsing legacy provider string
The ParseLegacyAbsProviderConfig was not detecting builtin providers
("terraform"), which caused issues for all users with 0.12 state and
the "terraform_remote_state" data source. Since "terraform" is the only
built-in provider this adds a very simple check to the parser so it
properly returns the builtin FQN.
* add tests to the addrs package
This commit reverts an earlier change which automatically converted
provider strings to legacy provider FQNs. It has become apparent that a
state upgrade step will be required before upgrading to v0.13.
a large refactor to addrs.AbsProviderConfig, embedding the addrs.Provider instead of a Type string. I've added and updated tests, added some Legacy functions to support older state formats and shims, and added a normalization step when reading v4 (current) state files (not the added tests under states/statefile/roundtrip which work with both current and legacy-style AbsProviderConfig strings).
The remaining 'fixme' and 'todo' comments are mostly going to be addressed in a subsequent PR and involve looking up a given local provider config's FQN. This is fine for now as we are only working with default assumption.
The state refactoring command "terraform state mv" in Terraform 0.11 does
not update existing dependency addresses recorded in the state when it
moves objects around, and Terraform only updates the dependency addresses
in the state when it performs a full update on a resource instance, and
so it's a common problem for folks updating from Terraform 0.11 with
resource names that are not valid identifiers to run into state upgrade
errors even though they have followed the instructions produced by
"terraform 0.12checklist".
Dependencies are synced from config during every refresh walk anyway, so
in practice we can get away with just discarding invalid dependency
addresses and letting the refresh walk update them. In practice these
addresses are unlikely to be pointing at a resource that actually exists
anyway, because if so Terraform 0.12's configuration parser wouldn't be
able to interpret it.
Discarding invalid dependency addresses allows the state upgrade to
complete successfully in such cases and thus gives the refresh step an
opportunity to repair the problem.
We're going to allow the provider to encode whatever it wants in here, so
a provider can use whatever is most convenient for its implementation
language and to avoid some of the bugs we saw with the prior model where
the forced round-trip through JSON and back into interface{} would cause
some loss of fidelity, leading to bugs.
Whereas the parent directory "states" contains the models that represent
state in memory, this package's responsibility is in serializing a subset
of that data to a JSON-based file format and then reloading that data
back into memory later.
For reading, this package supports state file formats going back to
version 1, using lightly-adapted versions of the migration code previously
used in the "terraform" package. State data is upgraded to the latest
version step by step and then transformed into the in-memory state
representation, which is distinct from any of the file format structs in
this package to enable these to evolve separately.
For writing, only the latest version (4) is supported, which is a new
format that is a slightly-flattened version of the new in-memory state
models introduced in the prior commit. This format retains the outputs
from only the root module and it flattens out the module and instance
parts of the hierarchy by including the identifiers for these inside
the child object. The loader then reconstructs the multi-layer structure
we use for more convenient access in memory.
For now, the only testing in this package is of round-tripping different
versions of state through a read and a write, ensuring the output is
as desired. This exercises all of the reading, upgrading, and writing
functions but should be augmented in later commits to improve coverage
and introduce more focused tests for specific parts of the functionality.
Alisdair McDiarmid