We've always had a mechanism to synchronize the Terraform state with
remote objects before creating a plan, but we previously kept the result
of that to ourselves, and so it would sometimes lead to Terraform
generating a planned action to undo some upstream drift, but Terraform
would give no context as to why that action was planned even though the
relevant part of the configuration hadn't changed.
Now we'll detect any differences between the previous run state and the
refreshed state and, if any managed resources now look different, show
an additional note about it as extra context for the planned changes that
follow.
This appears as an optional extra block of information before the normal
plan output. It'll appear the same way in all of the contexts where we
render plans, including "terraform show" for saved plans.
writeNestedAttrDiff and writeAttrDiff were both printing the "unchanged attribute" message. This removes one of the redundant prints.
Fixing this led me (in a very roundabout way) to realize that NestedType attributes were printing a sum total of unchanged attributes, including those in entirely unchanged elements, while *not* printing the total of unchanged elements. I added the necessary logic to count and print the number of unchanged elements for maps and lists.
If a JSON diagnostic value has a highlight end offset which is before
the highlight start offset, this would previously panic. This commit
adds a normalization step to prevent the crash.
This allows a similar effect to pre-tainting an object but does the action
within the context of a normal plan and apply, avoiding the need for an
intermediate state where the old object still exists but is marked as
tainted.
The core functionality for this was already present, so this commit is
just the UI-level changes to make that option available for use and to
explain how it contributed to the resulting plan in Terraform's output.
When rendering a plan diff, sensitive resource attributes would
previously omit the "forces replacement" comment, which can lead to
confusion when the only reason for a resource being replaced is a
sensitive attribute.
Previously we were repeating some logic in the UI layer in order to
recover relevant additional context about a change to report to a user.
In order to help keep things consistent, and to have a clearer path for
adding more such things in the future, here we capture this user-facing
idea of an "action reason" within the plan model, and then use that
directly in order to decide how to describe the change to the user.
For the moment the "tainted" situation is the only one that gets a special
message, matching what we had before, but we can expand on this in future
in order to give better feedback about the other replace situations too.
This also preemptively includes the "replacing by request" reason, which
is currently not reachable but will be used in the near future as part of
implementing the -replace=... plan command line option to allow forcing
a particular object to be replaced.
So far we don't have any special reasons for anything other than replacing,
which makes sense because replacing is the only one that is in a sense
a special case of another action (Update), but this could expand to
other kinds of reasons in the future, such as explaining which of the
few different reasons a data source read might be deferred until the
apply step.
* format/diff: extract attributes-writing logic to a function
This is a stepping-stone commit (for easier reviewability, and to prove that tests did not change) as part of writing a NestedType-specific diff printer.
* command/format: add support for formatting attributes with NestedTypes
This commit adds custom formatting for NestedType attributes. THe logic was mostly copied from the block diff printer, with minor tweaks here and there. I used the (excellent) existing test coverage and added a NestedType attribute to every test.
Since the (nested-block specific) test schemas were nearly identical, I added a function that returns the schema with the requested NestingMode.
This commit adds a comprehensive JSON format for diagnostics, which
ensures that all current diagnostic output can be semantically
represented in a machine-readable format. The diagnostic formatter
interface remains unchanged, but it first transforms its input via the
JSON format to ensure that there is only one code path for creating the
diagnostic data.
The JSON diagnostic renderer extracts the non-presentational logic from
the format package, and returns a structure which can either be
marshaled into JSON or rendered as text. The resulting text diagnostic
output is unchanged for all cases covered by unit tests and my own
manual testing.
Included in this commit are a number of golden reference files for the
marshaled JSON output of a diagnostic. This format should change rarely
if at all, and these are in place to ensure that any changes to the
format are intentional and considered.
* providers.Interface: huge renamification
This commit renames a handful of functions in the providers.Interface to
match changes made in protocol v6. The following commit implements this
change across the rest of the codebase; I put this in a separate commit
for ease of reviewing and will squash these together when merging.
One noteworthy detail: protocol v6 removes the config from the
ValidateProviderConfigResponse, since it's never been used. I chose to
leave that in place in the interface until we deprecate support for
protocol v5 entirely.
Note that none of these changes impact current providers using protocol
v5; the protocol is unchanged. Only the translation layer between the
proto and terraform have changed.
* command/format: check for sensitive NestedTypes
Eventually, the diff formatter will need to be updated to properly
handle NestedTypes, but for now we can let the existing function deal
with them as regular cty.Object-type attributes.
To avoid printing sensitive nested attributes, we will treat any
attribute with at least one sensitive nested attribute as an entirely
sensitive attribute.
* bugfix for Object ImpliedType()
ImpliedType() was returning too early when the given object had optional
attributes, therefore skipping the incredibly important step of
accounting for the nesting mode when returning said type.
Commit e865faf adds visual indentation for diagnostic messages using various
vertical line characters. The present commit disables this behaviour when
running with colourised output disabled.
While the contents of stderr are not intended to be part of the Terraform API,
this is currently how the hashicorp/terraform-exec library detects certain
error types in order to present them as well-known Go errors to the user. Such
detection is complicated when vertical lines are added to the CLI output at
unpredictable points.
I expect this change will also be helpful for screen reader users.
I frequently see people attempting to ask questions about Terraform's
error and warning messages but either only copying part of the message or
accidentally copying a surrounding paragraph that isn't part of the
message.
While I'm sure some of these are just "careless" mistakes, I've also
noticed that this has sometimes overlapped with someone asking a question
whose answer is written directly in the part of the message they didn't
include when copying, and so I have a theory that our current output
doesn't create a good enough visual hierarchy for sighted users to
understand where the diagnostic messages start and end when we show them
in close proximity to other content, or to other diagnostic messages.
As a result, some folks fail to notice the relevant message that might've
answered their question.
I tried a few different experiments for different approaches here, such
as adding more horizontal rules to the output and coloring the detail
text differently, but the approach that felt like the nicest compromise
to me was what's implemented here, which is to add a vertical line
along the left edge of each diagnostic message, colored to match with the
typical color we use for each diagnostic severity. This means that the
diagnostics end up slightly indented from what's around them, and the
vertical line seems to help subtly signal how we intended the content
to be grouped together.
In some terminal emulators, writing a character into the last column on a
row causes the terminal to immediately wrap to the beginning of the next
line, even if the very next character in the stream is a hard newline.
That can then lead to errant blank lines in the final output which make
it harder to navigate the visual hierarchy.
As a compromise to avoid this, we'll format our horizontal rules and
paragraphs to one column less than the terminal width. That does mean that
our horizontal rules won't _quite_ cover the whole terminal width, but
it seems like a good compromise in order to get consistent behavior across
a wider variety of terminal implementations.
We were previously using some ASCII art to create some visual divisions
between parts of the diagnostic output. Now that we are requiring a UTF-8
terminal we can print out box drawing characters instead.
We now require the output to accept UTF-8 and we can determine how wide
the terminal (if any) is, so here we begin to make use of that for the
"terraform plan" command.
The horizontal rule is now made of box drawing characters instead of
hyphens and fills the whole terminal width.
The paragraphs of text in the output are now also wrapped to fill the
terminal width, instead of the hard-wrapping we did before.
This is just a start down the road of making better use of the terminal
capabilities. Lots of other commands could benefit from updates like these
too.
* command/format: concise diff is no longer an experiment
Since state formatting goes through the "diff" printer, I have
repurposed the concise flag as a verbose flag, used only when printing
state. It's silly but it works!
* remove helper/experiment
With this experiment concluded, we no longer need helper/experiment. The
shadow experiment had not been touched in many years, so I removed all
references, and removed the package entirely. Any new experiments are
expected to be configuration experiments handled by our (other)
experiments package.
* check for the verbose flag consistently, in case we end up using it in plans in the future
Previously when printing the relevant variables involved in a failed
expression evaluation we would just skip over unknown values entirely.
There are some errors, though, which are _caused by_ a value being
unknown, in which case it's helpful to show which of the inputs to that
expression were known vs. unknown so that the user can limit their further
investigation only to the unknown ones.
While here I also added a special case for sensitive values that overrides
all other display, because we don't know what about a value is sensitive
and so better to give nothing away at the expense of a slightly less
helpful error message.
When an attribute's sensitivity changes, but its value remains the same,
we consider this an update operation for the plan. This commit updates
the diff renderer to match this, detecting and displaying the change in
sensitivity.
Previously, the renderer would detect no changes to the value of the
attribute, and consider it a no-op action. This resulted in suppression
of the attribute when the plan is in concise mode.
This is achieved with a new helper function, ctyEqualValueAndMarks. We
call this function whenever we want to check that two values are equal
in order to determine whether the action is update or no-op.
If an entire block is marked sensitive (possibly because it is of type
NestedSet) and results in replacement of the resource, we should render
the standard "forces replacement" text after the opening line of the
block.
If a value rendered for the diff is sensitive and results in replacement
of the resource, we should render the standard "forces replacement" text
after the "(sensitive)" value display.
When a value in a nested block is marked as sensitive,
it will result in the behavior of every member of
that block being sensitive. As such, show a
specialized diff that reduces noise of (sensitive)
for many attributes that we won't show. Also update
the warning to differentiate between showing a warning
for an attribute or warning for blocks.
Martin Atkins