feat: Implement triggers attribute for docker_image. (#425)

* feat: Implement triggers attribute for docker_image.

* fix: Update repo_digest value in test.

docs/resources/image.md

@@ -62,6 +62,20 @@ resource "docker_image" "zoo" {
 }
 ```
 
+You can use the `triggers` argument to specify when the image should be rebuild. This is for example helpful when you want to rebuild the docker image whenever the source code changes.
+
+```terraform
+resource "docker_image" "zoo" {
+  name = "zoo"
+  build {
+    path = "."
+  }
+  triggers = {
+    dir_sha1 = sha1(join("", [for f in fileset(path.module, "src/*") : filesha1(f)]))
+  }
+}
+```
+
 <!-- schema generated by tfplugindocs -->
 ## Schema
 
@@ -76,6 +90,7 @@ resource "docker_image" "zoo" {
 - `keep_locally` (Boolean) If true, then the Docker image won't be deleted on destroy operation. If this is false, it will delete the image from the docker local storage on destroy operation.
 - `pull_trigger` (String, Deprecated) A value which cause an image pull when changed
 - `pull_triggers` (Set of String) List of values which cause an image pull when changed. This is used to store the image digest from the registry when using the [docker_registry_image](../data-sources/registry_image.md).
+- `triggers` (Map of String) A map of arbitrary strings that, when changed, will force the `docker_image` resource to be replaced. This can be used to rebuild an image when contents of source code folders change
 
 ### Read-Only
 

examples/resources/docker_image/resource-build-triggers.tf

@@ -0,0 +1,9 @@
+resource "docker_image" "zoo" {
+  name = "zoo"
+  build {
+    path = "."
+  }
+  triggers = {
+    dir_sha1 = sha1(join("", [for f in fileset(path.module, "src/*") : filesha1(f)]))
+  }
+}

internal/provider/data_source_docker_image_test.go

@@ -32,7 +32,7 @@ func TestAccDockerImageDataSource_withSpecificTag(t *testing.T) {
 				Config: loadTestConfiguration(t, DATA_SOURCE, "docker_image", "testAccDockerImageDataSourceWithSpecificTag"),
 				Check: resource.ComposeTestCheckFunc(
 					resource.TestCheckResourceAttr("data.docker_image.foo", "name", imageName),
-					resource.TestCheckResourceAttr("data.docker_image.foo", "repo_digest", "busybox@sha256:a3170d3672568b2c6626710db3573f3d92ee31eed933c24f3d7ea978178e21b8"),
+					resource.TestCheckResourceAttr("data.docker_image.foo", "repo_digest", "busybox@sha256:09439c073bd3eb029a91c72eff2c0d9f12ab9c84f66bdef360fcf3f91a81bf7c"),
 				),
 			},
 		},

internal/provider/resource_docker_image.go

@@ -144,6 +144,12 @@ func resourceDockerImage() *schema.Resource {
 					},
 				},
 			},
+			"triggers": {
+				Description: "A map of arbitrary strings that, when changed, will force the `docker_image` resource to be replaced. This can be used to rebuild an image when contents of source code folders change",
+				Type:        schema.TypeMap,
+				Optional:    true,
+				ForceNew:    true,
+			},
 		},
 	}
 }

templates/resources/image.md.tmpl

@@ -33,4 +33,8 @@ In this case the image "zoo" and "zoo:develop" are built.
 
 {{tffile "examples/resources/docker_image/resource-build.tf"}}
 
+You can use the `triggers` argument to specify when the image should be rebuild. This is for example helpful when you want to rebuild the docker image whenever the source code changes.
+
+{{tffile "examples/resources/docker_image/resource-build-triggers.tf"}}
+
 {{ .SchemaMarkdown | trimspace }}