Use pre-installed Terraform plugins instead of downloading them with terraform init

You can use pre-installed plugins by either putting the plugins in the same directory as the terraform binary or by setting the -plugin-dir flag.

It's also possible to build a bundle of every provider you need automatically using the terraform-bundle tool.

I run Terraform in our CI pipeline in a Docker container so have a Dockerfile that looks something like this:

FROM golang:alpine AS terraform-bundler-build

RUN apk --no-cache add git unzip && \
    go get -d -v github.com/hashicorp/terraform && \
    go install ./src/github.com/hashicorp/terraform/tools/terraform-bundle

COPY terraform-bundle.hcl .

RUN terraform-bundle package terraform-bundle.hcl && \
    mkdir -p terraform-bundle && \
    unzip -d terraform-bundle terraform_*.zip

####################

FROM python:alpine

RUN apk add --no-cache git make && \
    pip install awscli

COPY --from=terraform-bundler-build /go/terraform-bundle/* /usr/local/bin/

Note that the finished container image also adds git, make and the AWS CLI as I also require those tools in the CI jobs that uses this container.

The terraform-bundle.hcl then looks something like this (taken from the terraform-bundle README):

terraform {
  # Version of Terraform to include in the bundle. An exact version number
  # is required.
  version = "0.10.0"
}

# Define which provider plugins are to be included
providers {
  # Include the newest "aws" provider version in the 1.0 series.
  aws = ["~> 1.0"]

  # Include both the newest 1.0 and 2.0 versions of the "google" provider.
  # Each item in these lists allows a distinct version to be added. If the
  # two expressions match different versions then _both_ are included in
  # the bundle archive.
  google = ["~> 1.0", "~> 2.0"]

  # Include a custom plugin to the bundle. Will search for the plugin in the 
  # plugins directory, and package it with the bundle archive. Plugin must have
  # a name of the form: terraform-provider-*, and must be build with the operating
  # system and architecture that terraform enterprise is running, e.g. linux and amd64
  customplugin = ["0.1"]
}

config plugin_cache_dir in .terraformrc

plugin_cache_dir   = "$HOME/.terraform.d/plugin-cache"

then move the pre-installed provider into the plugin_cache_dir,

terraform will not download the provider anymore

btw, use the ~/.terraform.d/plugin directory doesn't work

/.terraform.d/plugin/linux_amd64$ terraform -v
Terraform v0.12.15