Previously we would write to the backend for every call to PersistState,
even if nothing changed since the last write, but update the serial only
if the state had changed.
The Terraform Cloud & Enterprise state storage have a simple safety check
that any future write with an already-used lineage and serial must be
byte-for-byte identical. StatesMarshalEqual is intended to detect that,
but it only actually detects changes the state itself, and not changes
to the snapshot metadata.
Because we write the current Terraform version into the snapshot metadata
during serialization, we'd previously have an issue where if the first
state write after upgrading Terraform to a new version happened to change
nothing about the state content then we'd write a new snapshot that
differed only by Terraform version, and Terraform Cloud/Enterprise would
then reject it.
The snapshot header is discarded immediately after decoding, so we can't
use information from it when deciding whether to increment the serial.
The next best thing is to skip sending no-op snapshot updates to the state
client in the first place.
These writes are unnecessary anyway, and state storage owners have asked
us in the past to elide these to avoid generating noise in their version
logs, so we'll also finally meet those requests as a nice side-effect of
this change.
We didn't previously have tests for the full flow of retrieving and then
successively updating persisted state snapshots, so this includes a test
which covers that logic and includes an assertion that a no-op update does
not get written to the state client.
These statemgr interfaces are the new names for the older interfaces in
the "state" package. These types alias each other so it doesn't really
matter which we use, but the "state" package is deprecated and we intend
to eventually remove it, so this is a further step in that direction.
In our recent refactoring of the state manager interfaces we made serial
and lineage management the responsibility of the state managers
themselves, not exposing them at all to most callers, and allowing for
simple state managers that don't implement them at all.
However, we do have some specific cases where we need to preserve these
properly when available, such as migration between backends, and the
"terraform state push" and "terraform state pull" commands.
These new functions and their associated optional interface allow the
logic here to be captured in one place and access via some simple
calls. Separating this from the main interface leaves things simple for
the normal uses of state managers.
Since these functions are mostly just thin wrappers around other
functionality, they are not yet well-tested directly, but will be
indirectly tested through the tests of their callers. A subsequent commit
will add more unit tests here.
We were calling from PersistState into RefreshState, but RefreshState is
protected by the same lock as PersistState and so the call would deadlock.
Instead, we introduce a new entry point refreshState which can be used
when already holding the lock.
Most of the functionality in this package has been obsoleted by equivalent
symbols in states/statemgr. We're keeping this package around for the
moment mainly just to house the type aliases in state.go.
The tests in here no longer work because they are written against the old
APIs. We will eventually remove the components these are testing too, but
we're keeping them around for the moment so that we don't break the build
for some leftover callers that are still depending on these.
The state manager refactoring in an earlier commit was reflected in the
implementations of these backends, but not in their tests. This gets us
back to a state where the backend tests will compile, and gets _most_ of
them passing again, with a few exceptions that will be addressed in a
subsequent commit.
Due to how often the state and plan types are referenced throughout
Terraform, there isn't a great way to switch them out gradually. As a
consequence, this huge commit gets us from the old world to a _compilable_
new world, but still has a large number of known test failures due to
key functionality being stubbed out.
The stubs here are for anything that interacts with providers, since we
now need to do the follow-up work to similarly replace the old
terraform.ResourceProvider interface with its replacement in the new
"providers" package. That work, along with work to fix the remaining
failing tests, will follow in subsequent commits.
The aim here was to replace all references to terraform.State and its
downstream types with states.State, terraform.Plan with plans.Plan,
state.State with statemgr.State, and switch to the new implementations of
the state and plan file formats. However, due to the number of times those
types are used, this also ended up affecting numerous other parts of core
such as terraform.Hook, the backend.Backend interface, and most of the CLI
commands.
Just as with 5861dbf3fc49b19587a31816eb06f511ab861bb4 before, I apologize
in advance to the person who inevitably just found this huge commit while
spelunking through the commit history.
Only open a new file descriptor for RefreshState if we haven't written a
state, and don't have the correct state open already. This prevents
windows from failing to refresh a locked state.
Refreshing a locked state on windows could return nil if the read path
was locked, no state was yet written, and the read path is the same as
the write path.
Add a test that locks then refreshes a newly initialized state struct.
This PR changes manta from being a legacy remote state client to a new backend type. This also includes creating a simple lock within manta
This PR also unifies the way the triton client is configured (the schema) and also uses the same env vars to set the backend up
It is important to note that if the remote state path does not exist, then the backend will create that path. This means the user doesn't need to fall into a chicken and egg situation of creating the directory in advance before interacting with it
Update all references to the version values to use the new package.
The VersionString function was left in the terraform package
specifically for the aws provider, which is vendored. We can remove that
last call once the provider is updated.
Go 1.9 adds this new function which, when called, marks the caller as
being a "helper function". Helper function stack frames are then skipped
when trying to find a line of test code to blame for a test failure, so
that the code in the main test function appears in the test failure output
rather than a line within the helper function itself.
This covers many -- but probaly not all -- of our test helpers across
various packages.
- Configurable Put (store) method, default POST to preserve behavior
- Configurable Lock method & address
- Configurable Unlock method & address
More thorough testing still needed, but this if functional
Added locking support via blob leasing (requires that an empty state is
created before any lock can be acquired.
Added support for "environments" in much the same way as the S3 backend.
We can't check lineage in the remote state instance, because we may need
to overwrite a state with a new lineage. Whil it's tempting to add an
optional interface for this, like OverwriteState(), optional interfaces
are never _really_ optional, and will have to be implemented by any
wrapper types as well.
Another solution may be to add a State.Supersedes field to indicate that
we intend to replace an existing state, but that may not be worth the
extra check either.
In practice, States must all implement the full interface, so checking
for each method set only leaves gaps where tests could be skipped.
Change the helper to only accept a full state.State implementation.
Add some Lineage, Version, and TFVersion checks to TestState to avoid
regressions.
Compare the copy test against the immediate State returnedm rather than
our previous "current" state.
Check that the states round-trip and still marhsal identically via
MarshalEqual.
Previously we relied on a constellation of coincidences for everything to
work out correctly with state serials. In particular, callers needed to
be very careful about mutating states (or not) because many different bits
of code shared pointers to the same objects.
Here we move to a model where all of the state managers always use
distinct instances of state, copied when WriteState is called. This means
that they are truly a snapshot of the state as it was at that call, even
if the caller goes on mutating the state that was passed.
We also adjust the handling of serials so that the state managers ignore
any serials in incoming states and instead just treat each Persist as
the next version after what was most recently Refreshed.
(An exception exists for when nothing has been refreshed, e.g. because
we are writing a state to a location for the first time. In that case
we _do_ trust the caller, since the given state is either a new state
or it's a copy of something we're migrating from elsewhere with its
state and lineage intact.)
The intent here is to allow the rest of Terraform to not worry about
serials and state identity, and instead just treat the state as a mutable
structure. We'll just snapshot it occasionally, when WriteState is called,
and deal with serials _only_ at persist time.
This is intended as a more robust version of #15423, which was a quick
hotfix to an issue that resulted from our previous slopping handling
of state serials but arguably makes the problem worse by depending on
an additional coincidental behavior of the local backend's apply
implementation.
Move the Swift State from a legacy remote state to an official backend.
Add `container` and `archive_container` configuration variables, and deprecate `path` and `archive_path` variables.
Future improvements: Add support for locking and environments.
