When installing a provider which is already cached, we attempt to create
a symlink from the install directory targeting the cache. If symlinking
fails due to missing OS/filesystem support, we instead want to copy the
cached provider.
The fallback code to do this would always fail, due to a missing target
directory. This commit fixes that. I was unable to find a way to add
automated tests around this, but I have manually verified the fix on
Windows 8.1.
Providers installed from the registry are accompanied by a list of
checksums (the "SHA256SUMS" file), which is cryptographically signed to
allow package authentication. The process of verifying this has multiple
steps:
- First we must verify that the SHA256 hash of the package archive
matches the expected hash. This could be done for local installations
too, in the future.
- Next we ensure that the expected hash returned as part of the registry
API response matches an entry in the checksum list.
- Finally we verify the cryptographic signature of the checksum list,
using the public keys provided by the registry.
Each of these steps is implemented as a separate PackageAuthentication
type. The local archive installation mechanism uses only the archive
checksum authenticator, and the HTTP installation uses all three in the
order given.
The package authentication system now also returns a result value, which
is used by command/init to display the result of the authentication
process.
There are three tiers of signature, each of which is presented
differently to the user:
- Signatures from the embedded HashiCorp public key indicate that the
provider is officially supported by HashiCorp;
- If the signing key is not from HashiCorp, it may have an associated
trust signature, which indicates that the provider is from one of
HashiCorp's trusted partners;
- Otherwise, if the signature is valid, this is a community provider.
We previously skipped this one because it wasn't strictly necessary for
replicating the old "terraform init" behavior, but we do need it to work
so that things like the -plugin-dir option can behave correctly.
Linking packages from other cache directories and installing from unpacked
directories are fundamentally the same operation because a cache directory
is really just a collection of unpacked packages, so here we refactor
the LinkFromOtherCache functionality to actually be in
installFromLocalDir, and LinkFromOtherCache becomes a wrapper for
the installFromLocalDir function that just calculates the source and
target directories automatically and invalidates the metaCache.
When a provider source produces an HTTP URL location we'll expect it to
resolve to a zip file, which we'll first download to a temporary
directory and then treat it like a local archive.
When a provider source produces a local archive path we'll expect it to
be a zip file and extract it into the target directory.
This does not yet include an implementation of installing from an
already-unpacked local directory. That will follow in a subsequent commit,
likely following a similar principle as in Dir.LinkFromOtherCache.
Alisdair McDiarmid