63 lines
1.6 KiB
Markdown
63 lines
1.6 KiB
Markdown
---
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layout: "language"
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page_title: "coalesce - Functions - Configuration Language"
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sidebar_current: "docs-funcs-collection-coalesce-x"
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description: |-
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The coalesce function takes any number of arguments and returns the
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first one that isn't null nor empty.
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---
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# `coalesce` Function
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-> **Note:** This page is about Terraform 0.12 and later. For Terraform 0.11 and
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earlier, see
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[0.11 Configuration Language: Interpolation Syntax](../../configuration-0-11/interpolation.html).
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`coalesce` takes any number of arguments and returns the first one
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that isn't null or an empty string.
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All of the arguments must be of the same type. Terraform will try to
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convert mismatched arguments to the most general of the types that all
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arguments can convert to, or return an error if the types are incompatible.
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The result type is the same as the type of all of the arguments.
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## Examples
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```
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> coalesce("a", "b")
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a
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> coalesce("", "b")
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b
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> coalesce(1,2)
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1
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```
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To perform the `coalesce` operation with a list of strings, use the `...`
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symbol to expand the list as arguments:
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```
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> coalesce(["", "b"]...)
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b
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```
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Terraform attempts to select a result type that all of the arguments can
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convert to, so mixing argument types may produce surprising results due to
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Terraform's automatic type conversion rules:
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```
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> coalesce(1, "hello")
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"1"
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> coalesce(true, "hello")
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"true"
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> coalesce({}, "hello")
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Error: Error in function call
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Call to function "coalesce" failed: all arguments must have the same type.
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```
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## Related Functions
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* [`coalescelist`](./coalescelist.html) performs a similar operation with
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list arguments rather than individual arguments.
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