feat: Implement volume_options subpath (#710)

docs/resources/container.md

@@ -202,6 +202,7 @@ Optional:
 - `driver_options` (Map of String) key/value map of driver specific options.
 - `labels` (Block Set) User-defined key/value metadata. (see [below for nested schema](#nestedblock--mounts--volume_options--labels))
 - `no_copy` (Boolean) Populate volume with data from the target.
+- `subpath` (String) Path within the volume to mount. Requires docker server version 1.45 or higher.
 
 <a id="nestedblock--mounts--volume_options--labels"></a>
 ### Nested Schema for `mounts.volume_options.labels`

internal/provider/resource_docker_container.go

@@ -382,6 +382,12 @@ func resourceDockerContainer() *schema.Resource {
 										Optional:    true,
 										Elem:        &schema.Schema{Type: schema.TypeString},
 									},
+									"subpath": {
+										Type:        schema.TypeString,
+										Description: "Path within the volume to mount. Requires docker server version 1.45 or higher.",
+										Optional:    true,
+										ForceNew:    true,
+									},
 								},
 							},
 						},

internal/provider/resource_docker_container_funcs.go

@@ -209,6 +209,13 @@ func resourceDockerContainerCreate(ctx context.Context, d *schema.ResourceData,
 								}
 								mountInstance.VolumeOptions.DriverConfig.Options = mapTypeMapValsToString(value.(map[string]interface{}))
 							}
+							if client.ClientVersion() >= "1.45" {
+								if value, ok := rawVolumeOptions["subpath"]; ok {
+									mountInstance.VolumeOptions.Subpath = value.(string)
+								}
+							} else {
+								return diag.Errorf("Setting VolumeOptions.Subpath requires docker version 1.45 or higher")
+							}
 						}
 					}
 				}

internal/provider/resource_docker_container_structures.go

@@ -291,6 +291,9 @@ func getDockerContainerMounts(container container.InspectResponse) []map[string]
 				opt["driver_name"] = mount.VolumeOptions.DriverConfig.Name
 				opt["driver_options"] = mount.VolumeOptions.DriverConfig.Options
 			}
+			if mount.VolumeOptions.Subpath != "" {
+				opt["subpath"] = mount.VolumeOptions.Subpath
+			}
 			m["volume_options"] = []map[string]interface{}{
 				opt,
 			}