mergeBody is a hcl.Body implementation that deals with our override file
merging behavior for the portions of the configuration that are not
processed until full eval time.
Mimicking the behavior of our old config merge implementation from the
"config" package, the rules here are:
- Attributes in the override body hide attributes of the same name in
the base body.
- Any block in the override body hides all blocks with the same type name
that appear in the base body.
This is tested by a new test for the overriding of module arguments, which
asserts the correct behavior of the merged body as part of its work.
Some of the fields in our config structs are either mandatory in primary
files or there is a default value that we apply if absent.
Unfortunately override files impose the additional constraint that we
be allowed to omit required fields (which have presumably already been
set in the primary files) and that we are able to distinguish between a
default value and omitting a value entirely.
Since most of our fields were already acceptable for override files, here
we just add some new fields to deal with the few cases where special
handling is required and a helper function to disable the "Required" flag
on attributes in a given schema.
This method wraps LoadConfigFile to load all of the .tf and .tf.json files
in a given directory and then bundle them together into a Module object.
This function also deals with the distinction between primary and override
files, first appending together the primary files in lexicographic order
by filename, and then merging in override files in the same order.
The merging behavior is not fully implemented as of this commit, and so
will be expanded in future commits.
Much like TestParserLoadConfigFileSuccess, this is intended to be an
easy-to-maintain collection of bad examples to test different permutations
of our error handling.
As with TestParserLoadConfigFileSuccess, we should also have more specific
tests alongside this that check that the error outcome is what was
expected, since this test just accepts any error and may thus not be
testing what we think it is.
This test is intended to be an easy-to-maintain catalog of good examples
that we can use to catch certain parsing or decoding regressions easily.
It's not a fully-comprehensive test since it doesn't check the result
of decoding, instead just accepting any decode that completes without
errors. However, an easy-to-maintain test like this is a good complement
to some more specialized tests since we can easily collect good examples
over time and just add them in here.
This is a first pass of decoding of the main Terraform configuration file
format. It hasn't yet been tested with any real-world configurations, so
it will need to be revised further as we test it more thoroughly.
These types represent the individual elements within configuration, the
modules a configuration is made of, and the configuration (static module
tree) itself.
This method loads a "values file" -- also known as a "tfvars file" -- and
returns the values found inside.
A values file is an HCL file (in either native or JSON syntax) whose
top-level body is treated as a set of arbitrary key/value pairs whose
values may not depend on any variables or functions.
We will load values files through a configs.Parser -- even though values
files are not strictly-speaking part of configuration -- because this
causes them to be registered in our source code cache so that we can
generate source code snippets if we need to report any diagnostics.
configs.Parser is the entry-point for this package, providing functions to
load and parse HCL-based configuration files.
We use the library "afero" to decouple the parser from the physical OS
filesystem, which here allows us to easily use an in-memory filesystem
for testing and will, in future, allow us to read files from more unusual
places, such as configuration embedded in a plan file.
There's a lot of complexity in our existing "config" package that results
from our approach to handling configuration with HCL and HIL. A lot of
that functionality is no longer needed -- or must work in a significantly
different way -- for HCL2.
The new package "configs", which is named following the convention of some
Go standard library packages like "strings", is a re-imagination of some
of the functionality from the "config" package for an HCL2-only world.
The scope of this package will be slightly smaller than "config", since
it only deals with config loading and not with expression evaluation.
Another package "lang" (mentioned in the docstring here but not yet added)
will deal with the more dynamic portions of of configuration handling,
including populating an hcl.EvalContext to evaluate expressions.
Martin Atkins