gotf

README

gotf

gotf is a Terraform wrapper that makes it easy to support multiple configurations, e. g. for different environments.

Installation

GitHub Release

Download a release from GitHub:

https://github.com/unguiculus/gotf/releases

Homebrew

$ brew install unguiculus/gotf/gotf

Using go get

$ go get github.com/unguiculus/gotf

Usage

$ gotf --help

  ___   __  ____  ____
 / __) /  \(_  _)(  __)
( (_ \(  O ) )(   ) _)
 \___/ \__/ (__) (__)   v0.4.1 (commit=ee178b13db5e2620b5a931a09899a04a74d9c7d8, date=2020-01-28T16:29:01Z)

gotf is a Terraform wrapper facilitating configurations for various environments

Usage:
  gotf [flags] [Terraform args]

Flags:
  -c, --config string       Config file to be used (default "gotf.yaml")
  -d, --debug               Print additional debug output to stderr
  -h, --help                help for gotf
  -m, --module-dir string   The module directory to run Terraform in
  -p, --params key=value    Params for templating in the config file. May be specified multiple times (default map[])
      --version             version for gotf

gotf is configured via config file. By default, gotf.yaml is loaded from the current directory.

Example

# Optionally set a specific Terraform version. gotf will download this version and cache
# it in $XDG_CACHE_HOME/gotf/terraform/<version> verifying GPG signature and SHA256 sum
terraformVersion: 0.12.20

# tfvars files are added to the Terraform environment via
# TF_CLI_ARGS_<command>=-var-file=<file> for commands that support them.
# The are resolved relative to this file
varFiles:
  - test-{{ .Params.env }}.tfvars

# Variables are added to the Terraform environment via
# TF_VAR_<var>=value for commands that support them
vars:
  foo: foovalue
  templated_var: "{{ .Params.param }}"
  mapvar: |-
    {
      entry1 = {
        value1 = testvalue1
        value2 = true
      }
      entry2 = {
        value1 = testvalue2
        value2 = false
      }
    }
  module_path: "{{ .Params.moduleDir }}"
  module: "{{ base .Params.moduleDir }}"
  state_key_prefix: '{{ (splitn "_" 2 (base .Params.moduleDir))._1 }}'

# Environment variables are added to the Terraform calls environment
envs:
  BAR: barvalue
  TEMPLATED_ENV: "{{ .Params.param }}"

# Backend configs are always added as variables (TF_VAR_backend_<var>=value) for commands
# that support them and, if in case of 'init' additionally as '-backend-config' CLI options.
# Note the prefix 'backend_'  in the variable names.
backendConfigs:
  key: "{{ .Vars.state_key_prefix }}_{{ .Vars.templated_var }}_{{ .Params.key_suffix }}
  storage_account_name: be_storage_account_name_{{ .Vars.foo }}_{{ .Envs.BAR }}
  resource_group_name: be_resource_group_name_{{ .Vars.foo }}_{{ .Envs.BAR }}
  container_name: be_container_name_{{ .Vars.foo }}_{{ .Envs.BAR }}

Templating

Go templating can be used in the config file as follows. The Sprig function library is included.

• In the first templating pass, varFiles, vars, and envs are processed. All parameters specified using the -p|--param flag are available in the .Params object. The module directory passed with the --module-dir|-m parameter is available as module dir in the .Params object.
• In the second templating pass, backendConfigs are processed. vars are available as .Vars, envs are available as .Envs with the results from the first templating pass. Additionally, .Params is also available again.

Using the above config file, running terraform init could look like this:

$ gotf -c example-config.yaml -p param=myval -p key_suffix=mysuffix -m my_modules/01_testmodule init

After processing, the config file would look like this:

terraformVersion: 0.12.20

varFiles:
  - test-prod.tfvars

vars:
  foo: foovalue
  templated_var: "myval"
  mapvar: |-
    {
      entry1 = {
        value1 = testvalue1
        value2 = true
      }
      entry2 = {
        value1 = testvalue2
        value2 = false
      }
    }
  module_path: "my_modules/01_testmodule"
  module: "01_testmodule"
  state_key_prefix: 'testmodule'

envs:
  BAR: barvalue
  TEMPLATED_ENV: "myval"

backendConfigs:
  key: testmodule_myval_mysuffix
  storage_account_name: be_storage_account_name_foovalue_barvalue
  resource_group_name: be_resource_group_name_foovalue_barvalue
  container_name: be_container_name_foovalue_barvalue