Template

The Template resource allows the processing of templates, outputing the result as a file.

Templating uses the Handlebars language.

Examples

Template using HereDoc

The following example shows how the template can be embedded into the resource stanza using HereDoc syntax.

resource "template" "consul_config" {

  source = <<-EOF
  data_dir = "{{data_dir}}"
  log_level = "DEBUG"

  datacenter = "dc1"
  primary_datacenter = "dc1"

  server = true

  bootstrap_expect = 1
  ui = true

  bind_addr = "0.0.0.0"
  client_addr = "0.0.0.0"
  advertise_addr = "10.6.0.200"

  ports {
    grpc = 8502
  }

  connect {
    enabled = true
  }
  EOF

  destination = "./consul_config/consul.hcl"

  variables = {
    data_dir = "/tmp"
  }
}

The file produced from this example would look like the following

data_dir = "/tmp"
log_level = "DEBUG"

datacenter = "dc1"
primary_datacenter = "dc1"

server = true

bootstrap_expect = 1
ui = true

bind_addr = "0.0.0.0"
client_addr = "0.0.0.0"
advertise_addr = "10.6.0.200"

ports {
  grpc = 8502
}

connect {
  enabled = true
}

External Files

To leverage external files you can use the file function which loads a file returning a string. This example also shows how interpolation can be used to ensure a template is processed before it is consumed.

resource "template "consul_config" {

  source = file("./mytemplate.hcl") 
  destination = "./consul_config/consul.hcl"

  variables = {
    data_dir = "/tmp"
  }
}

container "consul" {
  depends_on = ["template.consul_config"]

  image   {
    name = "consul:${variable.consul_version}"
  }

  command = ["consul", "agent", "-config-file=/config/consul.hcl"]

  volume {
    source      = resource.template.consul_config.destination
    destination = "/config/consul.hcl"
  }
}

Inline variables

resource "template" "consul_config" {
  source = <<-EOF
  data_dir = "${data("test")}"
  log_level = "DEBUG"

  datacenter = "${variable.datacenter}"

  server = ${variable.server}
  EOF

  destination = "./consul_config/consul.hcl"
}

Template helpers

The template resource provides helpers that can be used inside your templates as shown in the example below.

resource "template" "consul_config" {
  source = <<-EOF
  file_content = "{{ file "./myfile.txt" }}"
  quote = {{quote something}} 
  trim = {{quote (trim with_whitespace)}}
  EOF

  destination = "./consul_config/consul.hcl"
}

quote

Returns the original string wrapped in quotations, quote can be used with the Go template pipe modifier.

// given the string 'abc'

quote "abc" // would return the value '"abc"'

trim

Removes whitespace such as carrige returns and spaces from the begining and the end of the string, can be used with the Go template pipe modifier.

// given the string ' abc '

trim " abc " // would return the value 'abc'