feat: Implement use_legacy_builder attribute

Author: Junkern

.github/workflows/acc-test.yaml

@@ -91,7 +91,14 @@ jobs:
           else:
             provider_bases = set()
             other_go_change = False
+            buildx_build_changed = False
             for f in go_files:
+              # This file doesn't follow the resource/data_source naming convention,
+              # but changes here affect image build/push behaviors.
+              if f.endswith('docker_buildx_build.go'):
+                buildx_build_changed = True
+                continue
+
               base = base_type_from_provider_file(f)
               if base:
                 provider_bases.add(base)
@@ -120,6 +127,14 @@ jobs:
               should_run = True
             else:
               selected = sorted({test_prefix_for_base(b) for b in provider_bases})
+
+              # docker_buildx_build.go impacts both image-related and registry image flows.
+              if buildx_build_changed:
+                selected = sorted(set(selected) | {
+                  'TestAccDockerImage',
+                  'TestAccDockerRegistryImage',
+                })
+
               should_run = True
 
               # Drop prefixes that don't match any tests in this repo.

docs/resources/image.md

@@ -86,7 +86,11 @@ resource "docker_image" "zoo" {
 
 -> **Note**: The buildx feature is currently in preview and may have some quirks. Known issues: Setting `ulimits` will not work.
 
-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`.
+If buildx is available, the provider will use it by default.
+
+To force the legacy builder, set `use_legacy_builder = true` in the `build` block.
+
+To select a specific buildx builder, set the `builder` argument (for the default buildx builder, use `default`). For a custom buildx builder, set `builder` to the builder name (see `docker buildx ls`).
 
 The single platform build result is automatically loaded to `docker images`.
 
@@ -159,6 +163,7 @@ Optional:
 - `tag` (List of String) Name and optionally a tag in the 'name:tag' format
 - `target` (String) Set the target build stage to build
 - `ulimit` (Block List) Configuration for ulimits (see [below for nested schema](#nestedblock--build--ulimit))
+- `use_legacy_builder` (Boolean) Force using the legacy Docker builder for image builds, even if buildx/buildkit would be available.
 - `version` (String) Version of the underlying builder to use
 
 <a id="nestedblock--build--auth_config"></a>

docs/resources/registry_image.md

@@ -105,6 +105,7 @@ Optional:
 - `tag` (List of String) Name and optionally a tag in the 'name:tag' format
 - `target` (String) Set the target build stage to build
 - `ulimit` (Block List) Configuration for ulimits (see [below for nested schema](#nestedblock--build--ulimit))
+- `use_legacy_builder` (Boolean) Force using the legacy Docker builder for image builds, even if buildx/buildkit would be available.
 - `version` (String) Version of the underlying builder to use
 
 <a id="nestedblock--build--auth_config"></a>

internal/provider/resource_docker_image.go

@@ -443,6 +443,13 @@ var buildSchema = &schema.Resource{
 			Optional:    true,
 			ForceNew:    true,
 		},
+		"use_legacy_builder": {
+			Type:        schema.TypeBool,
+			Description: "Force using the legacy Docker builder for image builds, even if buildx/buildkit would be available.",
+			Optional:    true,
+			Default:     false,
+			ForceNew:    true,
+		},
 		"builder": {
 			Type:        schema.TypeString,
 			Description: "The name of the buildx builder to use. If BUILDX_BUILDER environment variable is set, it will be used. If left empty, the provider tries to resolve to the default builder - which might not always work. If you are in Windows, the legacy builder is used.",

internal/provider/resource_docker_image_funcs.go

@@ -57,11 +57,16 @@ func resourceDockerImageCreate(ctx context.Context, d *schema.ResourceData, meta
 
 func buildImage(ctx context.Context, rawBuild interface{}, client *client.Client, imageName string) (bool, diag.Diagnostics) {
 	rawBuildValue := rawBuild.(map[string]interface{})
+	useLegacyBuilder, _ := rawBuildValue["use_legacy_builder"].(bool)
 	// now we need to determine whether we can use buildx or need to use the legacy builder
 	canUseBuildx, err := canUseBuildx(ctx, client)
 	if err != nil {
 		return true, diag.FromErr(err)
 	}
+	if useLegacyBuilder {
+		log.Printf("[DEBUG] use_legacy_builder=true, forcing legacy builder")
+		canUseBuildx = false
+	}
 
 	log.Printf("[DEBUG] canUseBuildx: %v", canUseBuildx)
 	// buildx is enabled

templates/resources/image.md.tmpl

@@ -47,7 +47,11 @@ You can use the `triggers` argument to specify when the image should be rebuild.
 
 -> **Note**: The buildx feature is currently in preview and may have some quirks. Known issues: Setting `ulimits` will not work.
 
-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`.
+If buildx is available, the provider will use it by default.
+
+To force the legacy builder, set `use_legacy_builder = true` in the `build` block.
+
+To select a specific buildx builder, set the `builder` argument (for the default buildx builder, use `default`). For a custom buildx builder, set `builder` to the builder name (see `docker buildx ls`).
 
 The single platform build result is automatically loaded to `docker images`.