As we continue iterating towards saving valid hashes for a package in a
depsfile lock file after installation and verifying them on future
installation, this prepares getproviders for the possibility of having
multiple valid hashes per package.
This will arise in future commits for two reasons:
- We will need to support both the legacy "zip hash" hashing scheme and
the new-style content-based hashing scheme because currently the
registry protocol is only able to produce the legacy scheme, but our
other installation sources prefer the content-based scheme. Therefore
packages will typically have a mixture of hashes of both types.
- Installing from an upstream registry will save the hashes for the
packages across all supported platforms, rather than just the current
platform, and we'll consider all of those valid for future installation
if we see both successful matching of the current platform checksum and
a signature verification for the checksums file as a whole.
This also includes some more preparation for the second case above in that
signatureAuthentication now supports AcceptableHashes and returns all of
the zip-based hashes it can find in the checksums file. This is a bit of
an abstraction leak because previously that authenticator considered its
"document" to just be opaque bytes, but we want to make sure that we can
only end up trusting _all_ of the hashes if we've verified that the
document is signed. Hopefully we'll make this better in a future commit
with some refactoring, but that's deferred for now in order to minimize
disruption to existing codepaths while we work towards a provider locking
MVP.
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.
This is the pre-existing hashing scheme that was initially built for
releases.hashicorp.com and then later reused for the provider registry
protocol, which takes a SHA256 hash of the official distribution .zip file
and formats it as lowercase hex.
This is a non-ideal hash scheme because it works only for
PackageLocalArchive locations, and so we can't verify package directories
on local disk against such hashes. However, the registry protocol is now
a compatibility constraint and so we're going to need to support this
hashing scheme for the foreseeable future.
We previously had this just stubbed out because it was a stretch goal for
the v0.13.0 release and it ultimately didn't make it in.
Here we fill out the existing stub -- with a minor change to its interface
so it can access credentials -- with a client implementation that is
compatible with the directory structure produced by the
"terraform providers mirror" subcommand, were the result to be published
on a static file server.
We previously had this functionality available for cached packages in the
providercache package. This moves the main implementation of this over
to the getproviders package and then implements it also for PackageMeta,
allowing us to compute hashes in a consistent way across both of our
representations of a provider package.
The new methods on PackageMeta will only be effective for packages in the
local filesystem because we need direct access to the contents in order
to produce the hash. Hopefully in future the registry protocol will be
able to also provide hashes using this content-based (rather than
archive-based) algorithm and then we'll be able to make this work for
PackageMeta referring to a package obtained from a registry too, but
hashes for local packages only are still useful for some cases right now,
such as generating mirror directories in the "terraform providers mirror"
command.
Martin Atkins