Due to how deeply the configuration types go into Terraform Core, there
isn't a great way to switch out to HCL2 gradually. As a consequence, this
huge commit gets us from the old state to a _compilable_ new state, but
does not yet attempt to fix any tests and has a number of known missing
parts and bugs. We will continue to iterate on this in forthcoming
commits, heading back towards passing tests and making Terraform
fully-functional again.
The three main goals here are:
- Use the configuration models from the "configs" package instead of the
older models in the "config" package, which is now deprecated and
preserved only to help us write our migration tool.
- Do expression inspection and evaluation using the functionality of the
new "lang" package, instead of the Interpolator type and related
functionality in the main "terraform" package.
- Represent addresses of various objects using types in the addrs package,
rather than hand-constructed strings. This is not critical to support
the above, but was a big help during the implementation of these other
points since it made it much more explicit what kind of address is
expected in each context.
Since our new packages are built to accommodate some future planned
features that are not yet implemented (e.g. the "for_each" argument on
resources, "count"/"for_each" on modules), and since there's still a fair
amount of functionality still using old-style APIs, there is a moderate
amount of shimming here to connect new assumptions with old, hopefully in
a way that makes it easier to find and eliminate these shims later.
I apologize in advance to the person who inevitably just found this huge
commit while spelunking through the commit history.
Implement debugInfo and the DebugGraph
DebugInfo will be a global variable through which graph debug
information can we written to a compressed archive. The DebugInfo
methods are all safe for concurrent use, and noop with a nil receiver.
The API outside of the terraform package will be to call SetDebugInfo
to create the archive, and CloseDebugInfo() to properly close the file.
Each write to the archive will be flushed and sync'ed individually, so
in the event of a crash or a missing call to Close, the archive can
still be recovered.
The DebugGraph is a representation of a terraform Graph to be written to
the debug archive, currently in dot format. The DebugGraph also contains
an internal buffer with Printf and Write methods to add to this buffer.
The buffer will be written to an accompanying file in the debug archive
along with the graph.
This also adds a GraphNodeDebugger interface. Any node implementing
`NodeDebug() string` can output information to annotate the debug graph
node, and add the data to the log. This interface may change or be
removed to provide richer options for debugging graph nodes.
The new graph builders all delegate the build to the BasicGraphBuilder.
Having a Name field lets us differentiate the actual builder
implementation in the debug graphs.
