Initial poseidon/cue Terraform provider

* Add cue_config data source to evaludate CUE contents
and render as JSON
* Evaluate inline CUE content
* Evaluate CUE files specified via paths list
* Support pretty_print option (default false)

.github/dependabot.yaml

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+version: 2
+updates:
+- package-ecosystem: gomod
+  directory: "/"
+  schedule:
+    interval: daily
+  pull-request-branch-name:
+    separator: "-"
+  open-pull-requests-limit: 3
+- package-ecosystem: github-actions
+  directory: "/"
+  schedule:
+    interval: daily

.github/workflows/test.yaml

@@ -0,0 +1,30 @@
+name: test
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+jobs:
+  build:
+    name: go
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        go: ['1.18', '1.19']
+    steps:
+      - name: setup Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: ${{matrix.go}}
+
+      - name: setup Terraform
+        uses: hashicorp/setup-terraform@v2
+        with:
+          terraform_wrapper: false
+
+      - name: checkout
+        uses: actions/checkout@v3
+
+      - name: test
+        run: make

.gitignore

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+bin/
+_output/

CHANGES.md

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+# terraform-provider-cue
+
+Notable changes between releases.
+
+## Latest
+
+## v0.1.0
+
+* Add `cue_config` data source to evaluate CUE contents
+  * Evaluate inline CUE `content`
+  * Evaluate CUE files specified via `paths` list
+  * Support `pretty_print` option (default false)
+  * Render CUE values as JSON

CONTRIBUTING.md

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+# Contributing
+
+## Developer Certificate of Origin
+
+By contributing, you agree to the Linux Foundation's Developer Certificate of Origin ([DCO](DCO)). The DCO is a statement that you, the contributor, have the legal right to make your contribution and understand the contribution will be distributed as part of this project.

DCO

@@ -0,0 +1,36 @@
+Developer Certificate of Origin
+Version 1.1
+
+Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
+660 York Street, Suite 102,
+San Francisco, CA 94110 USA
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+
+Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2022 Dalton Hubble
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

Makefile

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+export CGO_ENABLED:=0
+
+VERSION=$(shell git describe --tags --match=v* --always --dirty)
+SEMVER=$(shell git describe --tags --match=v* --always --dirty | cut -c 2-)
+
+.PHONY: all
+all: build test vet fmt
+
+.PHONY: build
+build: clean bin/terraform-provider-cue
+
+bin/terraform-provider-cue:
+	@go build -o $@ github.com/poseidon/terraform-provider-cue
+
+.PHONY: test
+test:
+	@go test ./... -cover
+
+.PHONY: vet
+vet:
+	@go vet -all ./...
+
+.PHONY: fmt
+fmt:
+	@test -z $$(go fmt ./...)
+
+.PHONY: clean
+clean:
+	@rm -rf bin
+	@rm -rf _output
+
+.PHONY: release
+release: \
+	clean \
+	_output/plugin-linux-amd64.zip \
+	_output/plugin-linux-arm64.zip \
+	_output/plugin-darwin-amd64.zip \
+	_output/plugin-darwin-arm64.zip \
+	_output/plugin-windows-amd64.zip
+
+_output/plugin-%.zip: NAME=terraform-provider-cue_$(SEMVER)_$(subst -,_,$*)
+_output/plugin-%.zip: DEST=_output/$(NAME)
+_output/plugin-%.zip: _output/%/terraform-provider-cue
+	@mkdir -p $(DEST)
+	@cp _output/$*/terraform-provider-cue $(DEST)/terraform-provider-cue_$(VERSION)
+	@zip -j $(DEST).zip $(DEST)/terraform-provider-cue_$(VERSION)
+
+_output/linux-amd64/terraform-provider-cue: GOARGS = GOOS=linux GOARCH=amd64
+_output/linux-arm64/terraform-provider-cue: GOARGS = GOOS=linux GOARCH=arm64
+_output/darwin-amd64/terraform-provider-cue: GOARGS = GOOS=darwin GOARCH=amd64
+_output/darwin-arm64/terraform-provider-cue: GOARGS = GOOS=darwin GOARCH=arm64
+_output/windows-amd64/terraform-provider-cue: GOARGS = GOOS=windows GOARCH=amd64
+_output/%/terraform-provider-cue:
+	$(GOARGS) go build -o $@ github.com/poseidon/terraform-provider-cue
+
+release-sign:
+	cd _output; sha256sum *.zip > terraform-provider-cue_$(SEMVER)_SHA256SUMS
+	gpg2 --detach-sign _output/terraform-provider-cue_$(SEMVER)_SHA256SUMS
+
+release-verify: NAME=_output/terraform-provider-cue
+release-verify:
+	gpg2 --verify $(NAME)_$(SEMVER)_SHA256SUMS.sig $(NAME)_$(SEMVER)_SHA256SUMS

README.md

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+# terraform-provider-cue
+[![GoDoc](https://pkg.go.dev/badge/github.com/poseidon/terraform-provider-cue.svg)](https://pkg.go.dev/github.com/poseidon/terraform-provider-cue) [![Workflow](https://github.com/poseidon/terraform-provider-cue/actions/workflows/test.yaml/badge.svg)](https://github.com/poseidon/terraform-provider-cue/actions/workflows/test.yaml?query=branch%3Amain) ![Downloads](https://img.shields.io/github/downloads/poseidon/terraform-provider-cue/total) [![Sponsors](https://img.shields.io/github/sponsors/poseidon?logo=github)](https://github.com/sponsors/poseidon) [![Twitter](https://img.shields.io/badge/follow-news-1da1f2?logo=twitter)](https://twitter.com/poseidonlabs)
+
+`terraform-provider-cue` allows Terraform to evaluate [CUE](https://cuelang.org/docs/) configs and render as JSON for use in Terraform.
+
+<details>
+  <summary>Author's Note</summary>
+  CUE has potential to be a better Jsonnet (if it gets a proper module manager). But like Jsonnet, its usage should be limited to preparing JSON-only configs where there are no viable alternatives (e.g. Grafana dashboards). Prefer native Terraform where possible, its ecosystem and design is simpler, more powerful, more mature, and ubiquitous.
+</details>
+
+## Usage
+
+Configure the `cue` provider (e.g. `providers.tf`).
+
+```tf
+provider "cue" {}
+
+terraform {
+  required_providers {
+    ct = {
+      source  = "poseidon/cue"
+      version = "0.1.0"
+    }
+  }
+}
+```
+
+Run `terraform init` to ensure version requirements are met.
+
+```
+$ terraform init -upgrade
+```
+
+Define a `cue_config` data source to validate CUE `content`.
+
+```tf
+data "cue_config" "example" {
+  content = <<EOF
+a: 1
+b: 2
+sum: a + b
+_hidden: 3
+l: [a, b]
+
+map: [string]:int
+map: {a: 1 * 5}
+map: {"b": b * 5}
+EOF
+  pretty_print = true
+}
+```
+
+Alternately, provide `paths` to CUE files (supports imports).
+
+```tf
+data "cue_config" "example" {
+  paths = [
+    "core.cue",
+    "box.cue",
+  ]
+  pretty_print = false
+}
+```
+
+Render the CUE config as JSON for use in Terraform expressions.
+
+```tf
+output "out" {
+  description = "Show Cue rendered as JSON"
+  value       = data.cue_config.example.rendered
+}
+```
+
+The rendered `content` example looks like:
+
+```json
+{
+  "a": 1,
+  "b": 2,
+  "sum": 3,
+  "l": [
+    1,
+    2
+  ],
+  "map": {
+    "a": 5,
+    "b": 10
+  }
+}
+```
+
+## Requirements
+
+* Terraform v1.0+ [installed](https://www.terraform.io/downloads.html)
+
+## Development
+
+### Binary
+
+To develop the provider plugin locally, build an executable with Go v1.18+.
+
+```
+make
+```

cue.mod/module.cue

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+module: "github.com/poseidon/terraform-provider-cue"

docs/data-sources/cue_config.md

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+# cue_config Data Source
+
+`cue_config` allows Terraform to evaluate [CUE](https://cuelang.org/docs/) configs and render JSON for usage.
+
+## Usage
+
+Define a `cue_config` data source to validate CUE `content`.
+
+```tf
+data "cue_config" "example" {
+  content = <<EOF
+a: 1
+b: 2
+sum: a + b
+_hidden: 3
+l: [a, b]
+
+map: [string]:int
+map: {a: 1 * 5}
+map: {"b": b * 5}
+EOF
+  pretty_print = true
+}
+```
+
+Alternately, provide `paths` to CUE files (supports imports).
+
+```tf
+data "cue_config" "example" {
+  paths = [
+    "core.cue",
+    "box.cue",
+  ]
+  pretty_print = false
+}
+```
+
+Render the CUE config as JSON for use in Terraform expressions.
+
+```tf
+output "out" {
+  description = "Show Cue rendered as JSON"
+  value       = data.cue_config.example.rendered
+}
+```
+
+## Argument Reference
+
+* `content` - inline CUE contents to evaluate (exclusive with `paths`)
+* `paths` - list of paths to CUE files (relative to Terraform workspace) to evaluate (exclusive with `content`)
+* `pretty_print` - indent rendered JSON for visual prettiness (default: false)
+
+## Argument Attributes
+
+* `rendered` - JSON output from evaluating CUE content(s)
+