@versusdev/terraform-switcher

Terraform Switcher

Inspired by warrensbox/terraform-switcher

The tfswitch command line tool lets you switch between different versions of terraform. If you do not have a particular version of terraform installed, tfswitch will download the version you desire. The installation is minimal and easy. Once installed, simply select the version you require from the dropdown and start using terraform.

Installation

tfswitch is available for MacOS and Linux based operating systems (Windows experemetal).

Homebrew

Installation for MacOS/Linux is the easiest with Homebrew. If you do not have homebrew installed, click here.

brew install versus/tap/tfswitch

Linux

Installation for other linux operation systems.

curl -L https://raw.githubusercontent.com/versus/terraform-switcher/release/install.sh | bash

Build and install SNAP package

snap install snapcraft --classic

snap install multipass

snapcraft

snap install terraform-switcher_*.snap --devmode --dangerous

tfswitch -v

multipass stop snapcraft-tfswitch && multipass delete snapcraft-tfswitch && multipass purge

Get binary releases or install from source

Alternatively, you can get releases or install the binary from source here

How to use:

Use dropdown menu to select version

1. You can switch between different versions of terraform by typing the command tfswitch on your terminal.
2. Select the version of terraform you require by using the up and down arrow.
3. Hit Enter to select the desired version.

The most recently selected versions are presented at the top of the dropdown.

Supply version on command line

1. You can also supply the desired version as an argument on the command line.
2. For example, tfswitch 0.10.5 for version 0.10.5 of terraform.
3. Hit Enter to switch.

See all versions including beta, alpha and release candidates(rc)

1. Display all versions including beta, alpha and release candidates(rc).
2. For example, tfswitch -l or tfswitch --list-all to see all versions.
3. Hit Enter to select the desired version.

Use version.tf file

If a .tf file with the terraform constrain is included in the current directory, it should automatically download or switch to that terraform version. For example, the following should automatically switch terraform to the lastest version:

terraform {
  required_version = ">= 0.12.9"

  required_providers {
    aws        = ">= 2.52.0"
    kubernetes = ">= 1.11.1"
  }
}

Use .tfswitch.toml file (For non-admin - users with limited privilege on their computers)

This is similiar to using a .tfswitchrc file, but you can specify a custom binary path for your terraform installation

1. Create a custom binary path. Ex: mkdir /Users/warrenveerasingam/bin (replace warrenveerasingam with your username)
2. Add the path to your PATH. Ex: export PATH=$PATH:/Users/warrenveerasingam/bin (add this to your bash profile or zsh profile)
3. Pass -b or --bin parameter with your custom path to install terraform. Ex: tfswitch -b /Users/warrenveerasingam/bin/terraform 0.10.8
4. Optionally, you can create a .tfswitch.toml file in your home directory for global settings.
5. Your .tfswitch.toml file should look like this:

bin = "/Users/versus/bin/terraform"
version = "0.11.3"

4. Run tfswitch and it should automatically install the required terraform version in the specified binary path

Alternatively, you can generate .tfswitch.toml in current directory just use tfswitch --init or tfswitch --init 0.13.2

Use .tfswitchrc file

1. Create a .tfswitchrc file containing the desired version
2. For example, echo "0.10.5" >> .tfswitchrc for version 0.10.5 of terraform
3. Run the command tfswitch in the same directory as your .tfswitchrc

Use environment variable TFSWITCH_PATH

1. Create a TFSWITCH_PATH environment variable with your custom path to install terraform Ex: export TFSWITCH_PATH=/Users/versus/bin/terraform
2. Run the command tfswitch

Instead of a .tfswitchrc file, a .terraform-version file may be used for compatibility with tfenv and other tools which use it

Automatically switch with bash

Add the following to the end of your ~/.bashrc file: (Use either .tfswitchrc or .tfswitch.toml or .terraform-version)

cdtfswitch(){
  builtin cd "$@";
  cdir=$PWD;
  if [ -e "$cdir/.tfswitchrc" ]; then
    tfswitch
  fi
}
alias cd='cdtfswitch'

Automatically switch with zsh

Add the following to the end of your ~/.zshrc file:

load-tfswitch() {
  local tfswitchrc_path=".tfswitchrc"

  if [ -f "$tfswitchrc_path" ]; then
    tfswitch
  fi
}
add-zsh-hook chpwd load-tfswitch
load-tfswitch

NOTE: if you see an error like this: command not found: add-zsh-hook, then you might be on an older version of zsh (see below), or you simply need to load add-zsh-hook by adding this to your .zshrc:

autoload -U add-zsh-hook

older version of zsh

cd(){
  builtin cd "$@";
  cdir=$PWD;
  if [ -e "$cdir/.tfswitchrc" ]; then
    tfswitch
  fi
}

Jenkins setup

#!/bin/bash 

echo "Installing tfswitch locally"
wget https://raw.githubusercontent.com/versus/terraform-switcher/release/install.sh 
chmod 755 install.sh
./install.sh -b bin-directory

./bin-directory/tfswitch

If you have limited permission, try:

#!/bin/bash 

echo "Installing tfswitch locally"
wget https://raw.githubusercontent.com/versus/terraform-switcher/release/install.sh 
chmod 755 install.sh
./install.sh -b bin-directory

CUSTOMBIN=`pwd`/bin             #set custom bin path
mkdir $CUSTOMBIN                #create custom bin path
export PATH=$PATH:$CUSTOMBIN    #Add custom bin path to PATH environment

./bin-directory/tfswitch -b $CUSTOMBIN/terraform 0.11.7

terraform -v                    #testing version

Circle CI setup

Example config yaml

version: 2
jobs:
  build:
    docker:
      - image: ubuntu

    working_directory: /go/src/github.com/versus/terraform-switcher

    steps:
      - checkout
      - run: 
          command: |    
            set +e   
            apt-get update 
            apt-get install -y wget 
            rm -rf /var/lib/apt/lists/*

            echo "Installing tfswitch locally"

            wget https://raw.githubusercontent.com/versus/terraform-switcher/release/install.sh 
            chmod 755 install.sh
            ./install.sh -b bin-directory

            CUSTOMBIN=`pwd`/bin             #set custom bin path
            mkdir $CUSTOMBIN                #create custom bin path
            export PATH=$PATH:$CUSTOMBIN    #Add custom bin path to PATH environment

            ./bin-directory/tfswitch -b $CUSTOMBIN/terraform 0.11.7

            terraform -v                    #testing version

Adds two new flags:

• no-symlink (n) Makes tfswitch detect and install a version only, without creating a permanent symlink to it. This allows tfswitch to be used as a helper when dynamically switching Terraform versions in environments where multiple tasks run with different versions in parallel, such as CI/CD agents.

• quiet (q) Makes tfswitch switch to a version if it's detected or specified as an argument, but prevents it from prompting the user for input if none is found or provided. This makes tfswitch more automation friendly.

Example use case on a CI/CD agent

An agent host is scheduled to run multiple Terraform Plan/Apply tasks simultaneously from different repositories, which each contain different Terraform configurations, using different versions of Terraform.

With a regular symlink approach, they would have to be queued and run synchronously, as a version switch would have to be made between each run.

However, if the terraform binary (or symlink) is replaced with a script (example below) that catches the arguments sent to terraform, performs a tfswitch using both the no-symlink and quiet flags, then catches the output from tfswitch and uses the desired binary to run the specific task, this can be done dynamically with each run, in parallel.

This utilizes tfswitch's brilliant ability to detect and install the required version, while allowing concurrency.

Example PoC script

#!/bin/bash

TF_DEFAULT_VERSION=0.13.2
TF_BIN_LOCATION=~/.terraform.versions

TF_SWITCH=`tfswitch-test -nq`
TF_DETECTED_VERSION=`echo "$TF_SWITCH" | awk -F '\"|\"' '{print $2}' | grep "\S"`

echo "$TF_SWITCH"

if [ "$TF_DETECTED_VERSION" == "" ]; then
    TF_DETECTED_VERSION=$TF_DEFAULT_VERSION
fi

TF_BIN="$TF_BIN_LOCATION/terraform_$TF_DETECTED_VERSION"

echo "Using version: $TF_DETECTED_VERSION"
echo ""

$TF_BIN "$@"

Suggestions and improvements are welcome.

-Sindre(c) https://github.com/sindrel

Issues

Please open issues here: New Issue