feat: Implement using of buildx for docker_image (#717)

* feat: Implement using of buildx for docker_image

* fix: secrets in docker_image

* fix: fmt issues

* test: Add test for build_log_file

* chore: Disable flaky test and update goreleaser to exclude not possible build

* feat: Small refactoring and documentation improvements

Author: Junkern

.goreleaser.yml

@@ -24,6 +24,8 @@ builds:
     ignore:
       - goos: darwin
         goarch: "386"
+      - goos: openbsd
+        goarch: arm
     binary: "{{ .ProjectName }}_v{{ .Version }}"
 archives:
   - format: zip

docs/resources/image.md

@@ -43,7 +43,7 @@ resource "docker_image" "ubuntu" {
 
 ### Build
 
-You can also use the resource to build an image.
+You can also use the resource to build an image. By default the build block is using the old legacy docker build. In order to use a buildx builder, please read the section below
 
 -> **Note**: The default timeout for the building is 20 minutes. If you need to increase this, you can use [operation timeouts](https://developer.hashicorp.com/terraform/language/resources/syntax#operation-timeouts).
 
@@ -81,6 +81,14 @@ resource "docker_image" "zoo" {
 }
 ```
 
+### Buildx
+
+-> **Note**: The buildx feature is currently in preview and may have some quirks. Known issues: Setting `ulimits` will not work.
+
+The `build` argument uses the legacy docker builder. If you want to use a buildx builder, you need to set the `builder` argument. For the default buildx builder, you can set the `builder` argument to `default`. For a custom buildx builder, you can set the `builder` argument to the name of the builder. You can find the name of the builder by running `docker buildx ls`.
+
+The single platform build result is automatically loaded to `docker images`.
+
 <!-- schema generated by tfplugindocs -->
 ## Schema
 
@@ -116,6 +124,8 @@ Optional:
 - `auth_config` (Block List) The configuration for the authentication (see [below for nested schema](#nestedblock--build--auth_config))
 - `build_args` (Map of String) Pairs for build-time variables in the form of `ENDPOINT : "https://example.com"`
 - `build_id` (String) BuildID is an optional identifier that can be passed together with the build request. The same identifier can be used to gracefully cancel the build with the cancel request.
+- `build_log_file` (String) Path to a file where the buildx log are written to. Only available when `builder` is set. If not set, no logs are available. The path is taken as is, so make sure to use a path that is available.
+- `builder` (String) Set the name of the buildx builder to use. If not set or empty, the legacy builder will be used.
 - `cache_from` (List of String) Images to consider as cache sources
 - `cgroup_parent` (String) Optional parent cgroup for the container
 - `cpu_period` (Number) The length of a CPU period in microseconds
@@ -135,9 +145,9 @@ Optional:
 - `no_cache` (Boolean) Do not use the cache when building the image
 - `platform` (String) Set platform if server is multi-platform capable
 - `pull_parent` (Boolean) Attempt to pull the image even if an older image exists locally
-- `remote_context` (String) A Git repository URI or HTTP/HTTPS context URI
+- `remote_context` (String) A Git repository URI or HTTP/HTTPS context URI. Will be ignored if `builder` is set.
 - `remove` (Boolean) Remove intermediate containers after a successful build. Defaults to `true`.
-- `secrets` (Block List) Set build-time secrets (see [below for nested schema](#nestedblock--build--secrets))
+- `secrets` (Block List) Set build-time secrets. Only available when you use a buildx builder. (see [below for nested schema](#nestedblock--build--secrets))
 - `security_opt` (List of String) The security options
 - `session_id` (String) Set an ID for the build session
 - `shm_size` (Number) Size of /dev/shm in bytes. The size must be greater than 0
@@ -176,7 +186,7 @@ Required:
 Optional:
 
 - `env` (String) Environment variable source of the secret
-- `src` (String) File source of the secret
+- `src` (String) File source of the secret. Takes precedence over `env`
 
 
 <a id="nestedblock--build--ulimit"></a>