adding proxy support

docs/index.md

@@ -43,20 +43,41 @@ provider "mist" {
 }
 ```
 
-<!-- schema generated by tfplugindocs -->
-## Schema
+### Credentials
 
-### Required
+Users are encouraged to pass the API Token or the username and password via the 
+environment variables (see below). If authentication information are provided 
+in the provider configuration and in the environment variables, the Provider
+configuration will be used.
 
-- `host` (String) URL of the Mist Cloud, e.g. `api.mist.com`.
-It is also possible to pass the Mist Cloud host with the environment variable `MIST_HOST`.
+Please consider whether writing credentials to a configuration file is
+acceptable in your environment.
+
+### Proxy Support
+
+HTTP, HTTPS, and SOCKS5 proxies are supported through the `MIST_PROXY` environment
+ variables or the `proxy` provider configuration attribute.
+
+<!-- schema generated by tfplugindocs -->
+## Schema
 
 ### Optional
 
 - `api_timeout` (Number) Timeout in seconds for completing API transactions with the Mist Cloud. Omit for default value of 10 seconds. Value of 0 results in infinite timeout.
 - `apitoken` (String, Sensitive) For API Token authentication, the Mist API Token.
-The preferred approach is to pass the API Token as environment variables `MIST_API_TOKEN`.
+- `host` (String) URL of the Mist Cloud, e.g. `api.mist.com`.
 - `password` (String, Sensitive) For username/password authentication, the Mist Account password.
-The preferred approach is to pass the API Token as environment variables `MIST_PASSWORD`.
+- `proxy` (String) Requests use the configured proxy to reach the Mist Cloud.
+The value may be either a complete URL or a `[username:password@]host[:port]`, in which case the `http` scheme is assumed. The schemes `http`, `https`, and `socks5` are supported.
 - `username` (String) For username/password authentication, the Mist Account username.
-The preferred approach is to pass the API Token as environment variables `MIST_USERNAME`.
+
+### Environment Variables
+
+| Varibale Name | Provider attribute | Type | Description |
+| ---- | ---- | ---- | ---- |
+| `MIST_HOST` | `host` | String | URL of the Mist Cloud, e.g. `api.mist.com`. See above for the list of supported Clouds.|
+| `MIST_API_TOKEN` | `apitoken` | String | For API Token authentication, the Mist API Token. |
+| `MIST_USERNAME` | `username` | String | For username/password authentication, the Mist Account password. |
+| `MIST_PASSWORD` | `password` | String | For username/password authentication, the Mist Account password. |
+| `MIST_PROXY` | `proxy` | String | Requests use the configured proxy to reach the Mist Cloud. The value may be either a complete URL or a `[username:password@]host[:port]`, in which case the `http` scheme is assumed. The schemes `http`, `https`, and `socks5` are supported. |
+| `MIST_API_TIMEOUT` | `api_timeout` | Int | Timeout in seconds for completing API transactions with the Mist Cloud. Omit for default value of 10 seconds. Value of 0 results in infinite timeout. |

internal/provider/constants.go

@@ -6,6 +6,7 @@ const (
 	envUsername          = "MIST_USERNAME"
 	envPassword          = "MIST_PASSWORD"
 	envApiTimeout        = "MIST_API_TIMEOUT"
+	envProxy             = "MIST_PROXY"
 	docCategorySeparator = " --- "
 	docCategorySite      = "Site" + docCategorySeparator
 	docCategoryOrg       = "Org" + docCategorySeparator