Previously we would only ever add new lock entries or update existing
ones. However, it's possible that over time a module may _cease_ using
a particular provider, at which point we ought to remove it from the lock
file so that operations won't fail when seeing that the provider cache
directory is inconsistent with the lock file.
Now the provider installer (EnsureProviderVersions) will remove any lock
file entries that relate to providers not included in the given
requirements, which therefore makes the resulting lock file properly match
the set of packages the installer wrote into the cache.
This does potentially mean that someone could inadvertently defeat the
lock by removing a provider dependency, running "terraform init", then
undoing that removal, and finally running "terraform init" again. However,
that seems relatively unlikely compared to the likelihood of removing
a provider and keeping it removed, and in the event it _did_ happen the
changes to the lock entry for that provider would be visible in the diff
of the provider lock file as usual, and so could be noticed in code
review just as for any other change to dependencies.
In historical versions of Terraform the responsibility to check this was
inside the terraform.NewContext function, along with various other
assorted concerns that made that function particularly complicated.
More recently, we reduced the responsibility of the "terraform" package
only to instantiating particular named plugins, assuming that its caller
is responsible for selecting appropriate versions of any providers that
_are_ external. However, until this commit we were just assuming that
"terraform init" had correctly selected appropriate plugins and recorded
them in the lock file, and so nothing was dealing with the problem of
ensuring that there haven't been any changes to the lock file or config
since the most recent "terraform init" which would cause us to need to
re-evaluate those decisions.
Part of the game here is to slightly extend the role of the dependency
locks object to also carry information about a subset of provider
addresses whose lock entries we're intentionally disregarding as part of
the various little edge-case features we have for overridding providers:
dev_overrides, "unmanaged providers", and the testing overrides in our
own unit tests. This is an in-memory-only annotation, never included in
the serialized plan files on disk.
I had originally intended to create a new package to encapsulate all of
this plugin-selection logic, including both the version constraint
checking here and also the handling of the provider factory functions, but
as an interim step I've just made version constraint consistency checks
the responsibility of the backend/local package, which means that we'll
always catch problems as part of preparing for local operations, while
not imposing these additional checks on commands that _don't_ run local
operations, such as "terraform apply" when in remote operations mode.
This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.
If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.
This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.
If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.
Fixes#27506
Add a new flag `-lockfile=readonly` to `terraform init`.
It would be useful to allow us to suppress dependency lockfile changes
explicitly.
The type of the `-lockfile` flag is string rather than bool, leaving
room for future extensions to other behavior variants.
The readonly mode suppresses lockfile changes, but should verify
checksums against the information already recorded. It should conflict
with the `-upgrade` flag.
Note: In the original use-case described in #27506, I would like to
suppress adding zh hashes, but a test code here suppresses adding h1
hashes because it's easy for testing.
Co-authored-by: Alisdair McDiarmid <alisdair@users.noreply.github.com>
Previously we were expecting that the *hcl.File would always be non-nil,
even in error cases. That isn't always true, so now we'll be more robust
about it and explicitly return an empty locks object in that case, along
with the error diagnostics.
In particular this avoids a panic in a strange situation where the user
created a directory where the lock file would normally go. There's no
meaning to such a directory, so it would always be a mistake and so now
we'll return an error message about it, rather than panicking as before.
The error message for the situation where the lock file is a directory is
currently not very specific, but since it's HCL responsible for generating
that message we can't really fix that at this layer. Perhaps in future
we can change HCL to have a specialized error message for that particular
error situation, but for the sake of this commit the goal is only to
stop the panic and return a normal error message.
This won't be a typical usage pattern for normal code, but will be useful
for tests that need to work with locks as input so that they don't need to
write out a temporary file on disk just to read it back in immediately.
If a configuration requires a partial provider version (with some parts
unspecified), Terraform considers this as a constrained-to-zero version.
For example, a version constraint of 1.2 will result in an attempt to
install version 1.2.0, even if 1.2.1 is available.
When writing the dependency locks file, we previously would write 1.2.*,
as this is the in-memory representation of 1.2. This would then cause an
error on re-reading the locks file, as this is not a valid constraint
format.
Instead, we now explicitly convert the constraint to its zero-filled
representation before writing the locks file. This ensures that it
correctly round-trips.
Because this change is made in getproviders.VersionConstraintsString, it
also affects the output of the providers sub-command.
In this case, "atomic" means that there will be no situation where the
file contains only part of the newContent data, and therefore other
software monitoring the file for changes (using a mechanism like inotify)
won't encounter a truncated file.
It does _not_ mean that there can't be existing filehandles open against
the old version of the file. On Windows systems the write will fail in
that case, but on Unix systems the write will typically succeed but leave
the existing filehandles still pointing at the old version of the file.
They'll need to reopen the file in order to see the new content.
Previously we were just letting hclwrite do its default formatting
behavior here. The current behavior there isn't ideal anyway -- it puts
big data structures all on one line -- but even ignoring that our goal
for this file format is to keep things in a highly-normalized shape so
that diffs against the file are clear and easy to read.
With that in mind, here we directly control how we write that value into
the file, which means that later changes to hclwrite's list/set
presentation won't affect it, regardless of what form they take.
This changes the approach used by the provider installer to remember
between runs which selections it has previously made, using the lock file
format implemented in internal/depsfile.
This means that version constraints in the configuration are considered
only for providers we've not seen before or when -upgrade mode is active.
These are helper functions to give the installation UI some hints about
whether the lock file has changed so that it can in turn give the user
advice about it. The UI-layer callers of these will follow in a later
commit.
The logic for what constitutes a valid hash and how different hash schemes
are represented was starting to get sprawled over many different files and
packages.
Consistently with other cases where we've used named types to gather the
definition of a particular string into a single place and have the Go
compiler help us use it properly, this introduces both getproviders.Hash
representing a hash value and getproviders.HashScheme representing the
idea of a particular hash scheme.
Most of this changeset is updating existing uses of primitive strings to
uses of getproviders.Hash. The new type definitions are in
internal/getproviders/hash.go.
Although origin registries return specific [filename, hash] pairs, our
various different installation methods can't produce a structured mapping
from platform to hash without breaking changes.
Therefore, as a compromise, we'll continue to do platform-specific checks
against upstream data in the cases where that's possible (installation
from origin registry or network mirror) but we'll treat the lock file as
just a flat set of equally-valid hashes, at least one of which must match
after we've completed whatever checks we've made against the
upstream-provided checksums/signatures.
This includes only the minimal internal/getproviders updates required to
make this compile. A subsequent commit will update that package to
actually support the idea of verifying against multiple hashes.
It doesn't make sense for a built-in provider to appear in a lock file
because built-in providers have no version independent of the version of
Terraform they are compiled into.
We also exclude legacy providers here, because they were supported only
as a transitional aid to enable the Terraform 0.13 upgrade process and
are not intended for explicit selection.
The provider installer will, once it's updated to understand dependency
locking, use this concept to decide which subset of its selections to
record in the dependency lock file for reference for future installation
requests.
This is an initial implementation of writing locks back to a file on disk.
This initial implementation is incomplete because it does not write the
changes to the new file atomically. We'll revisit that in a later commit
as we return to polish these codepaths, once we've proven out this
package's design by integrating it with Terraform's provider installer.
This is the initial implementation of the parser/decoder portion of the
new dependency lock file handler. It's currently dead code because the
caller isn't written yet. We'll continue to build out this functionality
here until we have the basic level of both load and save functionality
before introducing this into the provider installer codepath.
Martin Atkins