terraform: expose providers to terraform 0.13

Terraform 0.13 adopts a new filesystem layout for plugins (illustrated below).

Terraform 0.12 and earlier
`plugins-dir/terraform-provider-aws_v3.7.0`

Terraform 0.13
`plugins-dir/registry.terraform.io/hashicorp/aws/3.7.0/linux_amd64/terraform-provider-aws_v3.7.0`

To support all packaged Terraform versions a shim is created at both locations.

This approach was inspired by https://github.com/numtide/generate-terraform-provider-shim

Terraform 0.13 provider documentation https://www.terraform.io/upgrade-guides/0-13.html#new-filesystem-layout-for-local-copies-of-providers

layout terraform providers filesystem in withPlugins

1 files changed, 26 insertions, 8 deletions

diff --git a/pkgs/applications/networking/cluster/terraform/default.nix b/pkgs/applications/networking/cluster/terraform/default.nix
index b531055a1bfc..5f2ef78b495b 100644
--- a/pkgs/applications/networking/cluster/terraform/default.nix
+++ b/pkgs/applications/networking/cluster/terraform/default.nix
@@ -1,5 +1,5 @@
 { stdenv, lib, buildEnv, buildGoPackage, fetchFromGitHub, makeWrapper, coreutils
-, runCommand, writeText, terraform-providers, fetchpatch }:
+, runCommand, runtimeShell, writeText, terraform-providers, fetchpatch }:
 
 let
   goPackagePath = "github.com/hashicorp/terraform";
@@ -59,6 +59,29 @@ let
         let
           actualPlugins = plugins terraform.plugins;
 
+          # Make providers available in Terraform 0.13 and 0.12 search paths.
+          pluginDir = lib.concatMapStrings (pl: let
+            inherit (pl) repo version GOOS GOARCH;
+            inherit (pl.passthru) providerSourceAddress;
+
+            shim = writeText "shim" ''
+              #!${runtimeShell}
+              exec ${pl}/bin/${repo}_v${version} \$@
+            '';
+            in ''
+              TF_0_13_PROVIDER_PATH=$out/plugins/${providerSourceAddress}/${version}/${GOOS}_${GOARCH}/${repo}_v${version}
+              mkdir -p "$(dirname $TF_0_13_PROVIDER_PATH)"
+
+              cp ${shim} "$TF_0_13_PROVIDER_PATH"
+              chmod +x "$TF_0_13_PROVIDER_PATH"
+
+              TF_0_12_PROVIDER_PATH=$out/plugins/${repo}_v${version}
+
+              cp ${shim} "$TF_0_12_PROVIDER_PATH"
+              chmod +x "$TF_0_12_PROVIDER_PATH"
+          ''
+          ) actualPlugins;
+
           # Wrap PATH of plugins propagatedBuildInputs, plugins may have runtime dependencies on external binaries
           wrapperInputs = lib.unique (lib.flatten
             (lib.catAttrs "propagatedBuildInputs"
@@ -87,15 +110,10 @@ let
             inherit (terraform) name;
             buildInputs = [ makeWrapper ];
 
-            buildCommand = ''
+            buildCommand = pluginDir + ''
               mkdir -p $out/bin/
               makeWrapper "${terraform}/bin/terraform" "$out/bin/terraform" \
-                --set NIX_TERRAFORM_PLUGIN_DIR "${
-                  buildEnv {
-                    name = "tf-plugin-env";
-                    paths = actualPlugins;
-                  }
-                }/bin" \
+                --set NIX_TERRAFORM_PLUGIN_DIR $out/plugins \
                 --prefix PATH : "${lib.makeBinPath wrapperInputs}"
             '';