Explicit version strings are actually also version constraints! And the special
comparisons we were doing to allow a range of compatible versions can also be
expressed as version constraints.
Bonus: also simplify the way we handle version check errors, by composing the
messages inline and only extracting the repetitive parts into a function.
The cloud backend (and remote before it) previously expected a TFC workspace's
`terraform-version` attribute to be either the magic string `"latest"` or an
explicit semver value. But a workspace might have a version constraint instead
(like `~> 1.1.0`), in which case the version check would blow up.
This commit checks whether `terraform-version` is a valid version constraint
before erroring out, and if so, returns success if the local version meets the
constraint.
Because it's not practical to deeply introspect the slice of version space
defined by a constraint, this check is slightly less robust than the version
comparisons below it:
- It can give a false OK on open-ended constraints like `>= 1.1.0`. Say you're
running 1.3.0, it changed the state format, and the TFE instance admin has
not yet added any 1.3.x Terraform versions; your workspace will now break.
- It will give a false not-OK when using different minor versions within a range
that we know to be compatible, e.g. remote constraint of `~> 0.15.0` and local
version of 1.1.0.
- This would be totally useless with the pre-0.14 versions of Terraform, where
patch releases could change state format... but we're not going back in time
to add this feature to them anyway.
Still, in the most common likely case (`~> x.y.z`), it'll complain at you (with
an error you can choose to override) if you're not using the same minor version,
and that seems proportionate, useful, and expected.
When a user runs `terraform refresh` we give them an error message that
tells them to run `terraform apply -refresh-state`. We could just run
that command for them, though. That is what this PR does.
These changes remove all of the preexisting version checking for
individual features, wiping the slate clean with an overall minimum
requirement of a future TFP-API-Version 2.5, which at the time of this
writing is expected to be TFE v202112-1.
It also actually provides that expected TFE version as an actionable
error message, rather than generically saying that it isn't supported or
using the somewhat opaque API version header.
The 'tfe' service was appended to with various versions to denote a new
'feature' implemented by a new 'service'. This quickly proved to not be
scalable, as adding an entry to the discovery document from every
feature is bad.
The new mechanism added was checking the TFP-API-Version header on
requests for a version, instead.
So we'll remove the separation here between different tfe service
'versions' and the separate 'state' service and Just Use TFE, as well as
the TFP-API-Version header for all feature versioning., as well as the
TFP-API-Version header for all feature versioning.
The previous conservative guarantee that we would not make backwards
incompatible changes to the state file format until at least Terraform
1.1 can now be extended. Terraform 0.14 through 1.1 will be able to
interoperably use state files, so we can update the remote backend
version compatibility check accordingly.
This is a port of https://github.com/hashicorp/terraform/pull/29645
This changes the 'name' strategy to always align the local configured
workspace name and the remote Terraform Cloud workspace, rather than the
implicit use of the 'default' unnamed workspace being used instead.
What this essentially means is that the Cloud integration does not fully
support workspaces when configured for a single TFC workspace (as was
the case with the 'remote' backend), but *does* use the
backend.Workspaces() interface to allow for normal local behaviors like
terraform.workspace to resolve to the correct name. It does this by
always setting the local workspace name when the 'name' strategy is
used, as a part of initialization.
Part of the diff here is exporting all the previously unexported types
for mapping workspaces. The command package (and init in particular)
needs to be able to handle setting the local workspace in this
particular scenario.
A mostly cosemetic change; The fields 'workspace' and 'prefix' don't
really describe well what they are from a caller, so change these to use
a workspaceMapping struct to convey they are for implementing workspace
mapping strategies from CLI -> TFC
The cloud package intends to implement a new integration for
Terraform Cloud/Enterprise. The purpose of this integration is to better
support TFC users; it will shed some overly generic UX and architecture,
behavior changes that are otherwise backwards incompatible in the remote
backend, and technical debt - all of which are vestiges from before
Terraform Cloud existed.
This initial commit is largely a porting of the existing 'remote'
backend, which will serve as an underlying implementation detail and not
be a typical user-level backend. This is because to re-implement the
literal backend interface is orthogonal to the purpose of this
integration, and can always be migrated away from later.
As this backend is considered an implementation detail, it will not be
registered as a declarable backend. Within these changes it is, for easy
of initial development and a clean diff.
Nick Fagerlund