feat: add terraform provider and example with basic GKE setup

.gitignore

@@ -19,6 +19,11 @@ node_modules
 .garden
 tmp/
 metadata.json
+*.tfstate
+*.tfstate.backup
+*.tfvars
+*.tfvars.json
+.terraform
 
 # TS cache on the CI
 ts-node-*

docs/reference/module-types/README.md

@@ -5,4 +5,5 @@
 * [Helm](./helm.md)
 * [Kubernetes](./kubernetes.md)
 * [Maven Container](./maven-container.md)
-* [Openfaas](./openfaas.md)
+* [Openfaas](./openfaas.md)
+* [Terraform](./terraform.md)

docs/reference/module-types/terraform.md

@@ -0,0 +1,338 @@
+# `terraform` reference
+
+Resolves a Terraform stack and either applies it automatically (if `autoApply: true`) or errors when the stack
+resources are not up-to-date.
+
+Stack outputs are made available as service outputs, that can be referenced by other modules under
+`\${runtime.services.<module-name>.outputs.<key>}`. You can template in those values as e.g. command arguments
+or environment variables for other services.
+
+Note that you can also declare a Terraform root in the `terraform` provider configuration by setting the
+`initRoot` parameter.
+This may be preferable if you need the outputs of the Terraform stack to be available to other provider
+configurations, e.g. if you spin up an environment with the Terraform provider, and then use outputs from
+that to configure another provider or other modules via `\${providers.terraform.outputs.<key>}` template
+strings.
+
+See the [Terraform guide](../../using-garden/terraform.md) for a high-level introduction to the `terraform`
+provider.
+
+Below is the schema reference. For an introduction to configuring Garden modules, please look at our [Configuration
+guide](../../using-garden/configuration-files.md).
+The [first section](#configuration-keys) lists and describes the available
+schema keys. The [second section](#complete-yaml-schema) contains the complete YAML schema.
+
+`terraform` modules also export values that are available in template strings. See the [Outputs](#outputs) section below for details.
+
+## Configuration keys
+
+### `apiVersion`
+
+The schema version of this module's config (currently not used).
+
+| Type     | Required | Allowed Values | Default          |
+| -------- | -------- | -------------- | ---------------- |
+| `string` | Yes      | "garden.io/v0" | `"garden.io/v0"` |
+
+### `kind`
+
+| Type     | Required | Allowed Values | Default    |
+| -------- | -------- | -------------- | ---------- |
+| `string` | Yes      | "Module"       | `"Module"` |
+
+### `type`
+
+The type of this module.
+
+| Type     | Required |
+| -------- | -------- |
+| `string` | Yes      |
+
+Example:
+
+```yaml
+type: "container"
+```
+
+### `name`
+
+The name of this module.
+
+| Type     | Required |
+| -------- | -------- |
+| `string` | Yes      |
+
+Example:
+
+```yaml
+name: "my-sweet-module"
+```
+
+### `description`
+
+| Type     | Required |
+| -------- | -------- |
+| `string` | No       |
+
+### `include`
+
+Specify a list of POSIX-style paths or globs that should be regarded as the source files for this
+module. Files that do *not* match these paths or globs are excluded when computing the version of the module,
+when responding to filesystem watch events, and when staging builds.
+
+Note that you can also _exclude_ files using the `exclude` field or by placing `.gardenignore` files in your
+source tree, which use the same format as `.gitignore` files. See the
+[Configuration Files guide](https://docs.garden.io/using-garden/configuration-files#including-excluding-files-and-directories) for details.
+
+Also note that specifying an empty list here means _no sources_ should be included.
+
+| Type            | Required |
+| --------------- | -------- |
+| `array[string]` | No       |
+
+Example:
+
+```yaml
+include:
+  - Dockerfile
+  - my-app.js
+```
+
+### `exclude`
+
+Specify a list of POSIX-style paths or glob patterns that should be excluded from the module. Files that
+match these paths or globs are excluded when computing the version of the module, when responding to filesystem
+watch events, and when staging builds.
+
+Note that you can also explicitly _include_ files using the `include` field. If you also specify the
+`include` field, the files/patterns specified here are filtered from the files matched by `include`. See the
+[Configuration Files guide](https://docs.garden.io/using-garden/configuration-files#including-excluding-files-and-directories)for details.
+
+| Type            | Required |
+| --------------- | -------- |
+| `array[string]` | No       |
+
+Example:
+
+```yaml
+exclude:
+  - tmp/**/*
+  - '*.log'
+```
+
+### `repositoryUrl`
+
+A remote repository URL. Currently only supports git servers. Must contain a hash suffix pointing to a specific branch or tag, with the format: <git remote url>#<branch|tag>
+
+Garden will import the repository source code into this module, but read the module's
+config from the local garden.yml file.
+
+| Type     | Required |
+| -------- | -------- |
+| `string` | No       |
+
+Example:
+
+```yaml
+repositoryUrl: "git+https://github.com/org/repo.git#v2.0"
+```
+
+### `allowPublish`
+
+When false, disables pushing this module to remote registries.
+
+| Type      | Required | Default |
+| --------- | -------- | ------- |
+| `boolean` | No       | `true`  |
+
+### `build`
+
+Specify how to build the module. Note that plugins may define additional keys on this object.
+
+| Type     | Required | Default               |
+| -------- | -------- | --------------------- |
+| `object` | No       | `{"dependencies":[]}` |
+
+### `build.dependencies[]`
+
+[build](#build) > dependencies
+
+A list of modules that must be built before this module is built.
+
+| Type            | Required | Default |
+| --------------- | -------- | ------- |
+| `array[object]` | No       | `[]`    |
+
+Example:
+
+```yaml
+build:
+  ...
+  dependencies:
+    - name: some-other-module-name
+```
+
+### `build.dependencies[].name`
+
+[build](#build) > [dependencies](#build.dependencies[]) > name
+
+Module name to build ahead of this module.
+
+| Type     | Required |
+| -------- | -------- |
+| `string` | Yes      |
+
+### `build.dependencies[].copy[]`
+
+[build](#build) > [dependencies](#build.dependencies[]) > copy
+
+Specify one or more files or directories to copy from the built dependency to this module.
+
+| Type            | Required | Default |
+| --------------- | -------- | ------- |
+| `array[object]` | No       | `[]`    |
+
+### `build.dependencies[].copy[].source`
+
+[build](#build) > [dependencies](#build.dependencies[]) > [copy](#build.dependencies[].copy[]) > source
+
+POSIX-style path or filename of the directory or file(s) to copy to the target.
+
+| Type     | Required |
+| -------- | -------- |
+| `string` | Yes      |
+
+### `build.dependencies[].copy[].target`
+
+[build](#build) > [dependencies](#build.dependencies[]) > [copy](#build.dependencies[].copy[]) > target
+
+POSIX-style path or filename to copy the directory or file(s).
+
+| Type     | Required | Default                   |
+| -------- | -------- | ------------------------- |
+| `string` | No       | `"<same as source path>"` |
+
+### `autoApply`
+
+If set to true, Garden will automatically run `terraform apply -auto-approve` when the stack is not up-to-date. Otherwise, a warning is logged if the stack is out-of-date, and an error thrown if it is missing entirely.
+Defaults to the value set in the provider config.
+
+| Type      | Required | Default |
+| --------- | -------- | ------- |
+| `boolean` | No       | `null`  |
+
+### `dependencies`
+
+The names of any services that this service depends on at runtime, and the names of any tasks that should be executed before this service is deployed.
+
+| Type            | Required | Default |
+| --------------- | -------- | ------- |
+| `array[string]` | No       | `[]`    |
+
+### `root`
+
+Specify the path to the working directory root—i.e. where your Terraform files are—relative to the module root.
+
+| Type     | Required | Default |
+| -------- | -------- | ------- |
+| `string` | No       | `"."`   |
+
+### `variables`
+
+A map of variables to use when applying the stack. You can define these here or you can place a `terraform.tfvars` file in the working directory root.
+If you specified `variables` in the `terraform` provider config, those will be included but the variables specified here take precedence.
+
+| Type     | Required |
+| -------- | -------- |
+| `object` | No       |
+
+### `version`
+
+The version of Terraform to use. Defaults to the version set in the provider config.
+
+| Type     | Required | Default    |
+| -------- | -------- | ---------- |
+| `string` | No       | `"0.12.7"` |
+
+
+## Complete YAML schema
+```yaml
+apiVersion: garden.io/v0
+kind: Module
+type:
+name:
+description:
+include:
+exclude:
+repositoryUrl:
+allowPublish: true
+build:
+  dependencies:
+    - name:
+      copy:
+        - source:
+          target: <same as source path>
+autoApply: null
+dependencies: []
+root: .
+variables:
+version: 0.12.7
+```
+
+## Outputs
+
+### Module outputs
+
+The following keys are available via the `${modules.<module-name>}` template string key for `terraform`
+modules.
+
+### `modules.<module-name>.buildPath`
+
+The build path of the module.
+
+| Type     | Required |
+| -------- | -------- |
+| `string` | Yes      |
+
+Example:
+
+```yaml
+buildPath: "/home/me/code/my-project/.garden/build/my-module"
+```
+
+### `modules.<module-name>.path`
+
+The local path of the module.
+
+| Type     | Required |
+| -------- | -------- |
+| `string` | Yes      |
+
+Example:
+
+```yaml
+path: "/home/me/code/my-project/my-module"
+```
+
+### `modules.<module-name>.version`
+
+The current version of the module.
+
+| Type     | Required |
+| -------- | -------- |
+| `string` | Yes      |
+
+Example:
+
+```yaml
+version: "v-17ad4cb3fd"
+```
+
+### `modules.<module-name>.outputs`
+
+The outputs defined by the module.
+
+| Type     | Required |
+| -------- | -------- |
+| `object` | Yes      |
+