This kinda-weird feature was previously quite severely under-documented in
terms of exactly what effect it has. This new documentation for it first
attempts to frame it as something that should be rarely used, and then
explains in more detail exactly how it behaves for different top-level
block types within the configuration.
As part of revamping the "Configuration" portion of the website for the
v0.12 release, here we update the Terraform Settings page to use a similar
"guide-like" writing style as the other updated pages in this section.
Previously we just listed out all of the functions in alphabetical order
inside the "Interpolation Syntax" page, but that format doesn't leave much
room for details and usage examples.
Now we give each function its own page, and categorize them for easier
navigation. While many functions are very simple and don't really warrant
a full page, certain functions do have additional details that are worth
mentioning and this structure scales better for those more complicated
functions.
So far this includes only the numeric and string functions. Other
categories will follow in subsequent commits.
This rewrite of the "Configuration Syntax" page now gives some more detail
on the top-level structural constructs and de-emphasizes the name "HCL"
as subordinate to "the Terraform language".
It also now includes some commentary on valid identifiers and comments,
and issues around character encodings and line endings.
In addition, we now have a new "Expressions" page that replaces the old
"Interpolation Syntax" page, covering the expression language features
we inherit from HCL and how they behave in the context of Terraform.
The "Expressions" page currently links to a page about the built-in
functions which does not yet exist. This will be created in a later
commit.
This adopts a more guide-like writing style, similar to what prior commits
have done to some other subsections of this section.
The data sources page has not got any real attention since the feature
was first added, and our vocabulary for describing them and their
lifecycle hadn't quite settled when the page was originally written. This
new version is consistent in how it uses "data source" to describe the
feature that providers offer and "data resource" to describe what is
created by a "data" block in configuration, which then allows us to
draw on the many shared features between both data and managed resources.
For the moment this waits until "data resource" is defined in order to
first introduce the qualifier "managed resource". We may wish to revise
this again to mention that more specific nomenclature in passing on the
"Resources" page, in case a user encounters it elsewhere and wants to
learn what it means without needing to be familiar with data resources
first.
This adopts a more guide-like writing style, similar to what prior commits
have done to some other subsections of this section.
Since we already have a whole top-level section devoted to modules, there
is no need for full coverage of all of their features here. Instead, this
section focuses on an an initial introduction to what modules are and
the basics of their usage within the Terraform language. We then link
to the main modules section for the full details.
This adopts a more guide-like writing style, similar to what prior commits
have done to some other subsections of this section.
In the process of writing this, I identified some unclear statements in
the "Resources" subsection, and so these are also revised here for
consistency with the output values documentation.
These revisions reflect this sub-section's new earlier placement in the
sub-section list, leading to a more guide-like style for the initial
sections.
Also includes some minor copy-editing to align terminology with that
introduced in the prior commit for the "Resources" docs page.
This is now the leading subsection of the Configuration section of the
docs, and so this rewrite intends to make it more "guide-like" and as
accessible as possible to those who are not yet familiar with other
Terraform concepts.
This rewrite also attempts to introduce some consistency into our
vocabulary, which should eventually be reflected throughout our
documentation. In particular:
- "Resource" refers to the block the user writes in configuration, while
"Resource _Type_" refers to what the provider defines. We previously
used "resource" for both of these interchangeably.
- "Resource" is no longer used to refer to what gets created and managed
in remote APIs as a result of a resource block in configuration. Lacking
a good distinct name for these, this guide uses the word "object",
qualifying it as "infrastructure object" or "remote object" where
necessary to retain clarity. This distinction is important to enable
a clear description of resource lifecycle.
- "Argument" refers to an element (attribute or block) within a resource
block. This terminology was already being used in some places, so we
embrace it here as a way to distinguish from "attribute", which is
what a resource _exports_ for use in expressions.
- Since interpolation is no longer needed to use expressions in the
language, the word "expression" is used to describe the definition of
a value that might involve some computation. Where necessary, this is
used with a modifier "arbitrary expression" to contrast with situations
where the set of allowed expression constructs is constrained.
The prior content on this page was little more than an instruction to
begin navigating the sub-sections of this section.
The new content aims to give a broad overview of some of the language
concepts and a syntax example, in order to create some context to help
the user navigate the subsections more easily.
This also introduces for the first time usage of the term "the Terraform
language". This was previously left un-named, leading to some awkward
sentence constructions elsewhere in the docs. This new name gives us
some specific terminology to use in order to contrast the language that
exists at Terraform's level of abstraction, defining the semantics, from
the underlying grammar provided by HCL.
With the additional configuration language features coming in Terraform
v0.12, our existing documentation structure is beginning to strain.
Here we reorganize the navigation slightly in order to introduce the
concepts in a more appropriate order so that we can reveal complexity
more gradually. Subsequent commits will revise the content of these
pages to better reflect the new sequencing.
The "Environment Variables" page is moved from the Configuration section
into the "Commands" section, since it is not considered a part of the
configuration language and thus more appropriate in the CLI documentation.
The old placement is reflective of the broader purpose that the
"Configuration" section had originally, but its new focus will be on
the Terraform language (.tf files) in particular, with other aspects of
customizing Terraforms behavior covered in other sections.
website: Reconcile docs about plugin discovery and downloading
I'm attempting to keep things simple for normal users while making sure we've
got the full behavior written down somewhere for plugin developers.
This commit doesn't stand alone; it's paired with a commit in the
terraform-website repo, to deal with some related content in the "extend"
section.
It's been a while since we made any significant updates to this page.
The main theme of this revamp is to ensure that we highlight how to
provide "ambient credentials" for each of the module sources using the
standard mechanisms for each source type.
While there, I also attempted a general cleanup to highlight the main
cases and make this less like a detailed description of all of
go-getter's esoteric features, and did some general copy-editing to write
it in our usual documentation "voice".
Based on some feedback on the initial draft, make some minor updates to
how information is presented in the preview upgrade guide for v0.12.
This also includes some minor copy-editing work to try to make the "voice"
more consistent between different sections of the guide.
After some discussion with "iamakulov" on Twitter it seems that the use
of the word "conflicts" and "merge conflicts" here was sounding like us
implicitly condoning the use of version control as a mechanism for
distributing local state files, which hasn't been recommended for quite
some time since remote state now provides a much more robust solution.
While here, I also tweaked some other language on this page for style and
for use of terminology we more commonly use in our more recent
documentation.
Following the examples as they were previously would cause errors
accessing demo.consul.io. Now we consistently set the scheme to https for
all examples that use demo.consul.io.
This also includes some other updates to the URLs, since the Consul demo
has been rebuilt with a different based configuration, and some general
formatting and copyediting changes in the Consul example.
Create-before-destroy dependencies are automatically ordered correctly
by terraform. Remove the old notice about requiring all dependencies to
have the same setting for create_before_destroy.
In an earlier commit we added the "Best Practices" situation to try to
clarify the intended uses of named workspaces and to warn against using
them as an alternative to system decomposition.
However, the prior statement was cautious in its recommendations in the
interests of being pragmatic, and as a result we've seen that users have
in some cases misunderstood or disregarded these recommendations.
The new "When to use Multiple Workspaces" section aims to be more explicit
that having multiple separate Terraform configurations is the preferred
solution for many use-cases, and that workspaces are intended for a
more limited set of use-cases around convenient development and testing.
It also emphasizes the analogy to version control branches that was just
a footnote in the prior text, to help the reader become familiar with the
concept by relating it to a concept and workflow they are hopefully
already familiar with.
This new section also attempts to provide a more elaborate description of
the proposed alternative when the goal is system decomposition. In the
long run some of this content would probably be better placed elsewhere
since it is useful advice even for users who never discover named
workspaces, but it can live here for the time being to limit the scope of
this change until we are ready to make more comprehensive revisions to
the docs in this area.
Finally, the introductory documentation here is adjusted slightly in
preparation for the intended future expansion of workspaces to include
stored variable values and, for more tailored backends like Terraform
Enterprise, a full log of prior operations. More revisions will be
required to cover the specifics of this later, but this new framing will
hopefully help users form a mental model of named workspaces that has
room for these future enhancements and the corresponding concept in
Terraform Enterprise, rather than our previous framing that workspaces
are fundamentally just named states.
Also:
- In the getting started guide, the TFE content was all tailored to the older
run-locally workflow. I've replaced it with some brief explanation and a link
to the dedicated TFE getting started guide.
- Fixed a sidebar link glitch in the configuration section. (Both "Terraform"
and "Terraform Enterprise" were marked as active if you were on the TFE page.)
- Renamed the "Terraform Enterprise" page "Terraform Push." (Some people have
gotten confused and landed on this page when trying to set up the `atlas`
remote backend.)
Martin Atkins