In Terraform 0.11 and earlier, the "terraform fmt" command was very
opinionated in the interests of consistency. While that remains its goal,
for pragmatic reasons Terraform 0.12 significantly reduced the number
of formatting behaviors in the fmt command. We've held off on introducing
0.12-and-later-flavored cleanups out of concern it would make it harder
to maintain modules that are cross-compatible with both Terraform 0.11
and 0.12, but with this aimed to land in 0.14 -- two major releases
later -- our new goal is to help those who find older Terraform language
examples learn about the more modern idiom.
More rules may follow later, now that the implementation is set up to
allow modifications to tokens as well as modifications to whitespace, but
for this initial pass the command will now apply the following formatting
conventions:
- 0.11-style quoted variable type constraints will be replaced with their
0.12 syntax equivalents. For example, "string" becomes just string.
(This change quiets a deprecation warning.)
- Collection type constraints that don't specify an element type will
be rewritten to specify the "any" element type explicitly, so
list becomes list(any).
- Arguments whose expressions consist of a quoted string template with
only a single interpolation sequence inside will be "unwrapped" to be
the naked expression instead, which is functionally equivalent.
(This change quiets a deprecation warning.)
- Block labels are given in quotes.
Two of the rules above are coming from a secondary motivation of
continuing down the deprecation path for two existing warnings, so authors
can have two active deprecation warnings quieted automatically by
"terraform fmt", without the need to run any third-party tools.
All of these rules match with current documented idiom as shown in the
Terraform documentation, so anyone who follows the documented style should
see no changes as a result of this. Those who have adopted other local
style will see their configuration files rewritten to the standard
Terraform style, but it should not make any changes that affect the
functionality of the configuration.
There are some further similar rewriting rules that could be added in
future, such as removing 0.11-style quotes around various keyword or
static reference arguments, but this initial pass focused only on some
rules that have been proven out in the third-party tool
terraform-clean-syntax, from which much of this commit is a direct port.
For now this doesn't attempt to re-introduce any rules about vertical
whitespace, even though the 0.11 "terraform fmt" would previously apply
such changes. We'll be more cautious about those because the results of
those rules in Terraform 0.11 were often sub-optimal and so we'd prefer
to re-introduce those with some care to the implications for those who
may be using vertical formatting differences for some semantic purpose,
like grouping together related arguments.
Previously we were just using hclwrite.Format, a token-only formatting
pass. Now we'll do that via the full hclwrite parser, getting the
formatting as a side-effect of the parsing and re-serialization.
This should have no change in observable behavior as-is, but in a future
commit we'll add some additional processing rules that modify the syntax
tree before re-serializing it.
Previously formatting was just a simple wrapper around hclwrite.Format.
That remains true here, but the call is factored out into a separate
method in preparation for making it also do some Terraform-specific
cleanups in a future commit.
Previously, diagnostic errors would display the filename and line
number, along with "(source code not available)". This is because the
fmt command directly loads and parses the configuration, instead of
using the config loader.
This commit registers the manually parsed source as a synthetic
configuration file, so that the diagnostic formatter can look up the
source for the range with the error and display it.
Previously we were using the experimental HCL 2 repository, but now we'll
shift over to the v2 import path within the main HCL repository as part of
actually releasing HCL 2.0 as stable.
This is a mechanical search/replace to the new import paths. It also
switches to the v2.0.0 release of HCL, which includes some new code that
Terraform didn't previously have but should not change any behavior that
matters for Terraform's purposes.
For the moment the experimental HCL2 repository is still an indirect
dependency via terraform-config-inspect, so it remains in our go.sum and
vendor directories for the moment. Because terraform-config-inspect uses
a much smaller subset of the HCL2 functionality, this does still manage
to prune the vendor directory a little. A subsequent release of
terraform-config-inspect should allow us to completely remove that old
repository in a future commit.
Any command using meta.defaultFlagSet *might* occasionally exit before
the flag package's output got written. This caused flag error messages
to get lost. This PR discards the flag package output in favor of
directly returning the error to the end user.
This possibility was lost in the rewrite to use HCL2, but it's used by
a number of external utilities and text editor integrations, so we'll
restore it here.
Using the stdin/stdout mode is generally preferable for text editor use
since it allows formatting of the in-memory buffer rather than directly
the file on disk, but for editors that don't have support for that sort of
tooling it can be convenient to just launch a single command and directly
modify the on-disk file.
Since the HCL formatter only works with tokens, it can in principle be
called with any input and produce some output. However, when given invalid
syntax it will tend to produce nonsensical results that may drastically
change the input file and be hard for the user to undo.
Since there's no strong reason to try to format an invalid or incomplete
file, we'll instead try parsing first and fail if parsing does not
complete successfully.
Since we talk directly to the HCL API here this is only a _syntax_ check,
and so it can be applied to files that are invalid in other ways as far
as Terraform is concerned, such as using unsupported top-level block types,
resource types that don't exist, etc.
A lot of commands used `c.Meta.flagSet()` to create the initial flagset for the command, while quite a few of them didn’t actually use or support the flags that are then added.
So I updated a few commands to use `flag.NewFlagSet()` instead to only add the flags that are actually needed/supported.
Additionally this prevents a few commands from using locking while they actually don’t need locking (as locking is enabled as a default in `c.Meta.flagSet()`.
This doesn't yet include test updates, since there are problems in core
currently blocking these tests from running. The tests will therefore be
updated in a subsequent commit.
* command/fmt: Document -diff doesn't disable -write
As noted in hashicorp/terraform#6343, this description misleadingly
suggested that the `-diff` option disables the `-write` option.
This isn't the case and because of the default options (described in
c753390) the behaviour of `terraform fmt -diff` is actually the same as
`terraform fmt -write -list -diff`.
Replace the "instead of rewriting" description to clarify that.
Documentation in hcl/fmtcmd is corrected in hashicorp/hcl#117 but it's not
really necessary to bump the dependency version.
* command/fmt: Show flag defaults in help text
These were documented on the website but not in the `-help` text. This
should help to clarify that you need to pass `-list=false -write=false
-diff` if you only want to see diffs.
Accordingly I've replaced the word "disabled" with "always false" in the
STDIN special cases so that it matches the terminology used in the defaults
and better indicates that it is overridden.
NB: The 3x duplicated defaults and documentation makes me feel uneasy once
again. I'm not sure how to solve that, though.
These options don't make sense when passing STDIN. `-write` will raise an
error because there is no file to write to. `-list` will always say
`<standard input>`. So disable whenever using STDIN, making the command
much simpler:
cat main.tf | terraform fmt -
So that you can do automatic formatting from an editor. You probably want to
disable the `-write` and `-list` options so that you just get the
re-formatted content, e.g.
cat main.tf | terraform fmt -write=false -list=false -
I've added a non-exported field called `input` so that we can override this
for the tests. If not specified, like in `commands.go`, then it will default
to `os.Stdin` which works on the command line.
The most common usage usage will be enabling the `-write` and `-list`
options so that files are updated in place and a list of any modified files
is printed. This matches the default behaviour of `go fmt` (not `gofmt`). So
enable these options by default.
This does mean that you will have to explicitly disable these if you want to
generate valid patches, e.g. `terraform fmt -diff -write=false -list=false`
This uses the `fmtcmd` package which has recently been merged into HCL. Per
the usage text, this rewrites Terraform config files to their canonical
formatting and style.
Some notes about the implementation for this initial commit:
- all of the fmtcmd options are exposed as CLI flags
- it operates on all files that have a `.tf` suffix
- it currently only operates on the working directory and doesn't accept a
directory argument, but I'll extend this in subsequent commits
- output is proxied through `cli.UiWriter` so that we write in the same way
as other commands and we can capture the output during tests
- the test uses a very simple fixture just to ensure that it is working
correctly end-to-end; the fmtcmd package has more exhaustive tests
- we have to write the fixture to a file in a temporary directory because it
will be modified and for this reason it was easier to define the fixture
contents as a raw string
Martin Atkins