160 lines
4.6 KiB
Plaintext
160 lines
4.6 KiB
Plaintext
---
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page_title: Upgrading to Terraform 0.8
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description: Upgrading to Terraform v0.8
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---
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# Upgrading to Terraform v0.8
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Terraform v0.8 is a major release and thus includes some backwards
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incompatibilities that you'll need to consider when upgrading. This guide is
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meant to help with that process.
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The goal of this guide is to cover the most common upgrade concerns and
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issues that would benefit from more explanation and background. The exhaustive
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list of changes will always be the
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[Terraform Changelog](https://github.com/hashicorp/terraform/blob/main/CHANGELOG.md).
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After reviewing this guide, we recommend reviewing the Changelog to check on
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specific notes about the resources and providers you use.
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## Newlines in Strings
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Newlines are no longer allowed in strings unless it is a heredoc or an
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interpolation. This improves the performance of IDE syntax highlighting
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of Terraform configurations and simplifies parsing.
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**Behavior that no longer works in Terraform 0.8:**
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```
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resource "null_resource" "foo" {
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value = "foo
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bar"
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}
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```
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**Valid Terraform 0.8 configuration:**
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```
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resource "null_resource" "foo" {
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value = "foo\nbar"
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value2 = <<EOF
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foo
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bar
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EOF
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# You can still have newlines within interpolations.
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value3 = "${lookup(
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var.foo, var.bar)}"
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}
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```
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**Action:** Use heredocs or escape sequences when you have a string with newlines.
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## Math Order of Operations
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Math operations now follow standard mathematical order of operations.
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Prior to 0.8, math ordering was simply left-to-right. With 0.8, `*`, `/`, and
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`%` are done before `+`, `-`.
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Some examples are shown below:
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```
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${1+5*2} => 11 (was 12 in 0.7)
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${4/2*5} => 10 (was 10 in 0.7)
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${(1+5)*2} => 12 (was 12 in 0.7)
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```
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**Action:** Use parantheses where necessary to be explicit about ordering.
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## Escaped Variables in Templates
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The `template_file` resource now requires that any variables specified
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in an inline `template` attribute are now escaped. This _does not affect_
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templates read from files either via `file()` or the `filename` attribute.
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Inline variables must be escaped using two dollar signs. `${foo}` turns into
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`$${foo}`.
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This is necessary so that Terraform doesn't try to interpolate the values
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before executing the template (for example using standard Terraform
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interpolations). In Terraform 0.7, we had special case handling to ignore
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templates, but this would cause confusion and poor error messages. Terraform
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0.8 requires explicitly escaping variables.
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**Behavior that no longer works in Terraform 0.8:**
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```
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data "template_file" "foo" {
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template = "${foo}"
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vars { foo = "value" }
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}
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```
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**Valid Terraform 0.8 template:**
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```
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data "template_file" "foo" {
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template = "$${foo}"
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vars { foo = "value" }
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}
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```
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**Action:** Escape variables in inline templates in `template_file` resources.
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## Escape Sequences Within Interpolations
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Values within interpolations now only need to be escaped once.
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The exact behavior prior to 0.8 was inconsistent. In many cases, users
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just added `\` until it happened to work. The behavior is now consistent:
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single escape any values that need to be escaped.
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For example:
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```
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${replace(var.foo, "\\", "\\\\")}
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```
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This will now replace `\` with `\\` throughout `var.foo`. Note that `\` and
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`\\` are escaped exactly once. Prior to 0.8, this required double the escape
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sequences to function properly.
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A less complicated example:
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```
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${replace(var.foo, "\n", "")}
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```
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This does what you expect by replacing newlines with empty strings. Prior
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to 0.8, you'd have to specify `\\n`, which could be confusing.
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**Action:** Escape sequences within interpolations only need to be escaped
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once.
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## New Internal Graphs
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The core graphs used to execute Terraform operations have been changed to
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support new features. These require no configuration changes and should work
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as normal.
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They were tested extensively during 0.7.x behind experimental
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flags and using the shadow graph. However, it is possible that there
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are still edge cases that aren't properly handled.
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While we believe it will be unlikely, if you find that something is not
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working properly, you may use the `-Xlegacy-graph` flag on any Terraform
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operation to use the old code path.
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This flag will be removed prior to 0.9 (the next major release after 0.8),
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so please report any issues that require this flag so we can make sure
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they become fixed.
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~> **Warning:** Some features (such as `depends_on` referencing modules)
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do not work on the legacy graph code path. Specifically, any features
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introduced in Terraform 0.8 won't work with the legacy code path. These
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features will only work with the new, default graphs introduced with
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Terraform 0.8.
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