3268a7eaba
So far the output command has had a default output format intended for human consumption and a JSON output format intended for machine consumption. However, until Terraform v0.14 the default output format for primitive types happened to be _almost_ a raw string representation of the value, and so users started using that as a more convenient way to access primitive-typed output values from shell scripts, avoiding the need to also use a tool like "jq" to decode the JSON. Recognizing that primitive-typed output values are common and that processing them with shell scripts is common, this commit introduces a new -raw mode which is explicitly intended for that use-case, guaranteeing that the result will always be the direct result of a string conversion of the output value, or an error if no such conversion is possible. Our policy elsewhere in Terraform is that we always use JSON for machine-readable output. We adopted that policy because our other machine-readable output has typically been complex data structures rather than single primitive values. A special mode seems justified for output values because it is common for root module output values to be just strings, and so it's pragmatic to offer access to the raw value directly rather than requiring a round-trip through JSON.
3.5 KiB
layout, page_title, sidebar_current, description
| layout | page_title | sidebar_current | description |
|---|---|---|---|
| docs | Command: output | docs-commands-output | The `terraform output` command is used to extract the value of an output variable from the state file. |
Command: output
The terraform output command is used to extract the value of
an output variable from the state file.
Usage
Usage: terraform output [options] [NAME]
With no additional arguments, output will display all the outputs for
the root module. If an output NAME is specified, only the value of that
output is printed.
The command-line flags are all optional. The list of available flags are:
-json- If specified, the outputs are formatted as a JSON object, with a key per output. IfNAMEis specified, only the output specified will be returned. This can be piped into tools such asjqfor further processing.-raw- If specified, Terraform will convert the specified output value to a string and print that string directly to the output, without any special formatting. This can be convenient when working with shell scripts, but it only supports string, number, and boolean values. Use-jsoninstead for processing complex data types.-no-color- If specified, output won't contain any color.-state=path- Path to the state file. Defaults to "terraform.tfstate". Ignored when remote state is used.
Examples
These examples assume the following Terraform output snippet.
output "instance_ips" {
value = aws_instance.web.*.public_ip
}
output "lb_address" {
value = aws_alb.web.public_dns
}
output "password" {
sensitive = true
value = var.secret_password
}
To list all outputs:
$ terraform output
instance_ips = [
"54.43.114.12",
"52.122.13.4",
"52.4.116.53"
]
lb_address = "my-app-alb-1657023003.us-east-1.elb.amazonaws.com"
password = <sensitive>
Note that outputs with the sensitive attribute will be redacted:
$ terraform output password
password = <sensitive>
To query for the DNS address of the load balancer:
$ terraform output lb_address
"my-app-alb-1657023003.us-east-1.elb.amazonaws.com"
To query for all instance IP addresses:
$ terraform output instance_ips
instance_ips = [
"54.43.114.12",
"52.122.13.4",
"52.4.116.53"
]
Use in automation
The terraform output command by default displays in a human-readable format,
which can change over time to improve clarity.
For scripting and automation, use -json to produce the stable JSON format.
You can parse the output using a JSON command-line parser such as
jq:
$ terraform output -json instance_ips | jq -r '.[0]'
54.43.114.12
For the common case of directly using a string value in a shell script, you
can use -raw instead, which will print the string directly with no extra
escaping or whitespace.
$ terraform output -raw lb_address
my-app-alb-1657023003.us-east-1.elb.amazonaws.com
The -raw option works only with values that Terraform can automatically
convert to strings. Use -json instead, possibly combined with jq, to
work with complex-typed values such as objects.
Terraform strings are sequences of Unicode characters rather than raw bytes,
so the -raw output will be UTF-8 encoded when it contains non-ASCII
characters. If you need a different character encoding, use a separate command
such as iconv to transcode Terraform's raw output.