provider/docker: Add support for a list of pull_triggers within the d…

…ocker_image resource.

builtin/providers/docker/resource_docker_image.go

@@ -28,9 +28,19 @@ func resourceDockerImage() *schema.Resource {
 			},
 
 			"pull_trigger": &schema.Schema{
-				Type:     schema.TypeString,
+				Type:          schema.TypeString,
+				Optional:      true,
+				ForceNew:      true,
+				ConflictsWith: []string{"pull_triggers"},
+				Deprecated:    "Use field pull_triggers instead",
+			},
+
+			"pull_triggers": &schema.Schema{
+				Type:     schema.TypeSet,
 				Optional: true,
 				ForceNew: true,
+				Elem:     &schema.Schema{Type: schema.TypeString},
+				Set:      schema.HashString,
 			},
 		},
 	}

builtin/providers/docker/resource_docker_image_funcs.go

@@ -188,15 +188,11 @@ func findImage(d *schema.ResourceData, client *dc.Client) (*dc.APIImages, error)
 		return nil, fmt.Errorf("Empty image name is not allowed")
 	}
 
-	foundImage := searchLocalImages(data, imageName)
-
-	if foundImage == nil {
-		if err := pullImage(&data, client, imageName); err != nil {
-			return nil, fmt.Errorf("Unable to pull image %s: %s", imageName, err)
-		}
+	if err := pullImage(&data, client, imageName); err != nil {
+		return nil, fmt.Errorf("Unable to pull image %s: %s", imageName, err)
 	}
 
-	foundImage = searchLocalImages(data, imageName)
+	foundImage := searchLocalImages(data, imageName)
 	if foundImage != nil {
 		return foundImage, nil
 	}

builtin/providers/docker/resource_docker_image_test.go

@@ -131,6 +131,6 @@ data "docker_registry_image" "foobarbaz" {
 }
 resource "docker_image" "foobarbaz" {
 	name = "${data.docker_registry_image.foobarbaz.name}"
-	pull_trigger = "${data.docker_registry_image.foobarbaz.sha256_digest}"
+	pull_triggers = ["${data.docker_registry_image.foobarbaz.sha256_digest}"]
 }
 `

website/source/docs/providers/docker/d/registry_image.html.markdown

@@ -23,7 +23,7 @@ data "docker_registry_image" "ubuntu" {
 
 resource "docker_image" "ubuntu" {
     name = "${data.docker_registry_image.ubuntu.name}"
-    pull_trigger = "${data.docker_registry_image.ubuntu.sha256_digest}"
+    pull_triggers = ["${data.docker_registry_image.ubuntu.sha256_digest}"]
 }
 ```
 

website/source/docs/providers/docker/r/image.html.markdown

@@ -14,7 +14,7 @@ Pulls a Docker image to a given Docker host from a Docker Registry.
 
 This resource will *not* pull new layers of the image automatically unless used in
 conjunction with [`docker_registry_image`](/docs/providers/docker/d/registry_image.html)
-data source to update the `pull_trigger` field.
+data source to update the `pull_triggers` field.
 
 ## Example Usage
 
@@ -36,7 +36,7 @@ data "docker_registry_image" "ubuntu" {
 
 resource "docker_image" "ubuntu" {
     name = "${data.docker_registry_image.ubuntu.name}"
-    pull_trigger = "${data.docker_registry_image.ubuntu.sha256_digest}"
+    pull_triggers = ["${data.docker_registry_image.ubuntu.sha256_digest}"]
 }
 ```
 
@@ -48,10 +48,12 @@ The following arguments are supported:
 * `keep_locally` - (Optional, 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` - (Optional, string) Used to store the image digest from the
-  registry and will cause an image pull when changed. Needed when using
-  the `docker_registry_image` [data source](/docs/providers/docker/d/registry_image.html)
-  to trigger an update of the image.
+* `pull_triggers` - (Optional, list of strings) 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 source](/docs/providers/docker/d/registry_image.html)
+  to trigger an image update.
+* `pull_trigger` - **Deprecated**, use `pull_triggers` instead.
+
 
 ## Attributes Reference