Add tests and remove resorce when the plan does not specify resource

Signed-off-by: gatici <[email protected]>

docs/resources/application.md

@@ -49,6 +49,24 @@ resource "juju_application" "placement_example" {
     external-hostname = "..."
   }
 }
+
+resource "juju_application" "custom_resources_example" {
+  name  = "placement-example"
+  model = juju_model.development.name
+  charm {
+    name     = "hello-kubecon"
+    channel  = "edge"
+    revision = 14
+    series   = "trusty"
+  }
+
+  resources = {
+    gosherve-image = "gatici/gosherve:1.0"
+  }
+
+  units     = 3
+  placement = "0,1,2"
+}
 ```
 
 <!-- schema generated by tfplugindocs -->
@@ -68,16 +86,27 @@ resource "juju_application" "placement_example" {
 - `name` (String) A custom name for the application deployment. If empty, uses the charm's name.
 - `placement` (String) Specify the target location for the application's units
 - `resources` (Map of String) Charm resource revisions. Must evaluate to a string. A resource could be a resource revision number or a custom resource.
-
-	There are a few scenarios that need to be considered:
-	* If the plan does not specify resource revision and resources are added to the plan,
-	resources with specified revisions will be attached to the application (equivalent
-	to juju attach-resource).
-	* If the plan does specify resource revisions and:
-		* If the charm revision or channel is updated, then resources get updated to the 
-		  latest revision.
-	    * If the charm revision or channel are not updated, then no changes will take 
-		  place (juju does not have an "un-attach" command for resources).
+There are a few scenarios that need to be considered:
+  * If the plan does not specify a resource and resources are added to the plan (as a revision number or a custom resource), specified resources are attached to the application (equivalent to juju attach-resource).
+  * If the plan does specify resource revisions and if the charm revision or channel is updated, existing resources are kept.  (Resources are not detached)
+  * If the plan does specify resource revisions and resources are removed from the plan:
+          - If charm revision/channel is updated, the resources associated with the updated charm revision or channel  is attached.
+          - If the charm revision/channel are not updated then the resources associated with the existing charm revision/channel are attached.
+  * Charm could be deployed without resource, then resource could be  added later.
+  * Resources could be provided in the following formats:
+          - A custom repository URL
+          - A files ends with .txt, .json  or .yaml
+          - A resource revision from CharmHub
+    * Charm could be deployed with resources.
+    * If the provided resource revision does not exist during initial deployment or update, Client does not start deployment with an error that resource was not found in the store.
+    * If the provided custom resource does not exist during initial deployment or update, Client  start deployment and charm could not be deployed properly and charm will be in error state.
+    * If the Provided resource type is not correct then Client fails with incorrect resource error for below scenarios:
+          - An image is expected but file does not include image URL
+          - A plain text file is expected but a .json file is provided.
+    *  If the provided resource does not exist then Client fails with path is not valid error.
+    *  Changing resources from a file to an int or string does not create any issue. Resources are processed smoothly.
+       -  If provided resource value is changed from an int to a file  then the image resource from the file is attached.
+       -  If provided resource value is changed from a file to an int then image revision is attached.
 - `trust` (Boolean) Set the trust for the application.
 - `units` (Number) The number of application units to deploy for the charm.
 

examples/resources/juju_application/resource.tf

@@ -33,4 +33,22 @@ resource "juju_application" "placement_example" {
   config = {
     external-hostname = "..."
   }
+}
+
+resource "juju_application" "custom_resources_example" {
+  name  = "placement-example"
+  model = juju_model.development.name
+  charm {
+    name     = "hello-kubecon"
+    channel  = "edge"
+    revision = 14
+    series   = "trusty"
+  }
+
+  resources = {
+    gosherve-image = "gatici/gosherve:1.0"
+  }
+
+  units     = 3
+  placement = "0,1,2"
 }

internal/juju/applications.go

@@ -61,8 +61,7 @@ const (
 	ContentTypeRaw = "application/octet-stream"
 )
 const (
-	// MediaTypeFormData is the media type for file uploads (see
-	// mime.FormatMediaType).
+	// MediaTypeFormData is the media type for file uploads (see mime.FormatMediaType).
 	MediaTypeFormData = "form-data"
 	// QueryParamPendingID is the query parameter we use to send up the pending id.
 	QueryParamPendingID = "pendingid"
@@ -76,14 +75,12 @@ const (
 	// HeaderContentLength is the header name for the length of a file upload.
 	HeaderContentLength = "Content-Length"
 	// HeaderContentDisposition is the header name for value that holds the filename.
-	// The params are formatted according to  RFC 2045 and RFC 2616 (see
-	// mime.ParseMediaType and mime.FormatMediaType).
+	// See mime.ParseMediaType and mime.FormatMediaType.
 	HeaderContentDisposition = "Content-Disposition"
 )
 
 const (
-	// HTTPEndpointPath is the URL path, with substitutions, for
-	// a resource request.
+	// HTTPEndpointPath is the URL path, with substitutions, for a resource request.
 	HTTPEndpointPath = "/applications/%s/resources/%s"
 )
 
@@ -115,8 +112,7 @@ type UploadRequest struct {
 
 type HttpRequestClient struct {
 	base.ClientFacade
-	facade base.FacadeCaller
-
+	facade     base.FacadeCaller
 	httpClient jujuhttp.HTTPDoer
 }
 
@@ -130,7 +126,7 @@ type applicationNotFoundError struct {
 var ApplicationNotFoundError = &applicationNotFoundError{}
 
 // newEndpointPath returns the API URL path for the identified resource.
-func newEndpointPath(application, name string) string {
+func newEndpointPath(application string, name string) string {
 	return fmt.Sprintf(HTTPEndpointPath, application, name)
 }
 
@@ -407,7 +403,7 @@ func (osFilesystem) Stat(name string) (os.FileInfo, error) {
 	return os.Stat(name)
 }
 
-// Checks if strings consists from digits
+// isInt checks if strings consists from digits
 // Used to detect resources which are given with revision number
 func isInt(s string) bool {
 	for _, c := range s {
@@ -486,10 +482,13 @@ func (c applicationsClient) deployFromRepository(applicationAPIClient *apiapplic
 		Trust:            transformedInput.trust,
 		Resources:        transformedInput.resources,
 	})
+
 	if len(errs) != 0 {
 		return errors.Join(errs...)
 	}
+
 	fileSystem := osFilesystem{}
+	// Upload the provided local resources to Juju
 	uploadErr := uploadExistingPendingResources(deployInfo.Name, localPendingResources, fileSystem, resourceHttpClient)
 
 	if uploadErr != nil {
@@ -499,7 +498,7 @@ func (c applicationsClient) deployFromRepository(applicationAPIClient *apiapplic
 }
 
 // TODO (hml) 23-Feb-2024
-// Remove the funcationality associated with legacyDeploy
+// Remove the functionality associated with legacyDeploy
 // once the provider no longer supports a version of juju
 // before 3.3.
 func (c applicationsClient) legacyDeploy(ctx context.Context, conn api.Connection, applicationAPIClient *apiapplication.Client, transformedInput transformedCreateApplicationInput) error {
@@ -1415,7 +1414,7 @@ func (c applicationsClient) computeSetCharmConfig(
 		Origin: resultOrigin,
 	}
 
-	resourceIDs, err := c.updateResources(input.AppName, input.Resources, charmsAPIClient, apiCharmID, resourcesAPIClient, resourceHttpClient)
+	resourceIDs, err := c.updateResources(input.AppName, input.Resources, charmsAPIClient, apiCharmID, resourcesAPIClient)
 	if err != nil {
 		return nil, err
 	}
@@ -1449,7 +1448,7 @@ func strPtr(in string) *string {
 }
 
 func (c applicationsClient) updateResources(appName string, resources map[string]string, charmsAPIClient *apicharms.Client,
-	charmID apiapplication.CharmID, resourcesAPIClient ResourceAPIClient, resourceHttpClient *HttpRequestClient) (map[string]string, error) {
+	charmID apiapplication.CharmID, resourcesAPIClient ResourceAPIClient) (map[string]string, error) {
 	meta, err := utils.GetMetaResources(charmID.URL, charmsAPIClient)
 	if err != nil {
 		return nil, err
@@ -1487,16 +1486,20 @@ func addPendingResources(appName string, resourcesToBeAdded map[string]charmreso
 					if err != nil {
 						return nil, typedError(err)
 					}
-					aux := charmresources.Resource{
+					resourceFromCharmhub := charmresources.Resource{
 						Meta:     resourceMeta,
 						Origin:   charmresources.OriginStore,
 						Revision: -1,
 					}
-					aux.Revision = providedRev
-					pendingResourcesforAdd = append(pendingResourcesforAdd, aux)
+					// If the resource is removed, revision does not exist
+					// Charm is deployed with default resources according to charm revision or channel
+					if providedRev != 0 {
+						resourceFromCharmhub.Revision = providedRev
+					}
+					pendingResourcesforAdd = append(pendingResourcesforAdd, resourceFromCharmhub)
 				} else {
 					// A new resource to be uploaded by the client
-					uux := charmresources.Resource{
+					localResource := charmresources.Resource{
 						Meta:   resourceMeta,
 						Origin: charmresources.OriginUpload,
 					}
@@ -1510,7 +1513,7 @@ func addPendingResources(appName string, resourcesToBeAdded map[string]charmreso
 					if openResErr != nil {
 						return nil, typedError(openResErr)
 					}
-					toRequestUpload, err := resourcesAPIClient.UploadPendingResource(appName, uux, deployValue, r)
+					toRequestUpload, err := resourcesAPIClient.UploadPendingResource(appName, localResource, deployValue, r)
 					if err != nil {
 						return nil, typedError(err)
 					}

internal/juju/applications_test.go

@@ -18,6 +18,7 @@ import (
 	"github.com/juju/names/v4"
 	"github.com/juju/utils/v3"
 	"github.com/juju/version/v2"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
 	"go.uber.org/mock/gomock"
 )
@@ -303,3 +304,19 @@ func (s *ApplicationSuite) TestReadApplicationRetrySubordinate() {
 func TestApplicationSuite(t *testing.T) {
 	suite.Run(t, new(ApplicationSuite))
 }
+
+func TestNewEndpointPath(t *testing.T) {
+	application := "ausf"
+	name := "sdcore-ausf-k8s"
+	want := "/applications/ausf/resources/sdcore-ausf-k8s"
+	got := newEndpointPath(application, name)
+	assert.Equal(t, got, want)
+}
+
+func TestNewEndpointPathEmptyInputs(t *testing.T) {
+	application := ""
+	name := ""
+	want := "/applications//resources/"
+	got := newEndpointPath(application, name)
+	assert.Equal(t, got, want)
+}

internal/juju/package_test.go

@@ -3,5 +3,5 @@
 
 package juju_test
 
-//go:generate go run go.uber.org/mock/mockgen -package juju -destination mock_test.go github.com/juju/terraform-provider-juju/internal/juju SharedClient,ClientAPIClient,ApplicationAPIClient,ModelConfigAPIClient,ResourceAPIClient,SecretAPIClient
+//go:generate go run go.uber.org/mock/mockgen -package juju -destination mock_test.go github.com/juju/terraform-provider-juju/internal/juju SharedClient,ClientAPIClient,ApplicationAPIClient,ModelConfigAPIClient,ResourceAPIClient,SecretAPIClient,HttpRequestClient,UploadRequest,ResourceHttpClient,osFilesystem,apicharms.Client,utils.GetUpgradeResources,charmresources.ParseType,resourcecmd.Opensource,typedError,io.ReadSeeker,http.Request,mime.Encoding.Encode,Mime.FormatMediaType,http.NewRequest
 //go:generate go run go.uber.org/mock/mockgen -package juju -destination jujuapi_mock_test.go github.com/juju/juju/api Connection

internal/provider/main_test.go

@@ -37,7 +37,7 @@ func (ct CloudTesting) String() string {
 
 // CloudName returns the cloud name as displayed
 // when using `juju list-clouds`. For example,
-// a controller can be bootstrapped with an lxd type.
+// a controller can be bootstrapped with an LXD type.
 // However, that's the controller type, the cloud name
 // would be localhost
 func (ct CloudTesting) CloudName() string {

internal/provider/provider_test.go

@@ -21,7 +21,7 @@ import (
 	"github.com/juju/terraform-provider-juju/internal/juju"
 )
 
-const TestProviderStableVersion = "0.10.1"
+const TestProviderStableVersion = "0.12.0"
 
 // providerFactories are used to instantiate the Framework provider during
 // acceptance testing.

internal/provider/resource_application.go

@@ -43,16 +43,26 @@ const (
 
 	resourceKeyMarkdownDescription = `
 Charm resource revisions. Must evaluate to a string. A resource could be a resource revision number or a custom resource.
-
-	There are a few scenarios that need to be considered:
-	* If the plan does not specify resource revision and resources are added to the plan,
-	resources with specified revisions will be attached to the application (equivalent
-	to juju attach-resource).
-	* If the plan does specify resource revisions and:
-		* If the charm revision or channel is updated, then resources get updated to the 
-		  latest revision.
-	    * If the charm revision or channel are not updated, then no changes will take 
-		  place (juju does not have an "un-attach" command for resources).
+There are a few scenarios that need to be considered:
+  * If the plan does not specify a resource and resources are added to the plan (as a revision number or a custom resource), specified resources are attached to the application (equivalent to juju attach-resource).
+  * If the plan does specify resource revisions and if the charm revision or channel is updated, existing resources are kept.  (Resources are not detached)
+  * If the plan does specify resource revisions and resources are removed from the plan:
+          - If charm revision/channel is updated, the resources associated with the updated charm revision or channel  is attached.
+          - If the charm revision/channel are not updated then the resources associated with the existing charm revision/channel are attached.
+  * Charm could be deployed without resource, then resource could be  added later.
+  * Resources could be provided in the following formats:
+          - A custom repository URL
+          - A files ends with .txt, .json  or .yaml
+          - A resource revision from CharmHub
+    * Charm could be deployed with resources.
+    * If the provided resource revision does not exist during initial deployment or update, Client does not start deployment with an error that resource was not found in the store.
+    * If the provided custom resource does not exist during initial deployment or update, Client  start deployment and charm could not be deployed properly and charm will be in error state.
+    *  If the Provided resource type is not correct then Client fails with incorrect resource error for below scenarios:
+          - An image is expected but file does not include image URL
+          - A plain text file is expected but a .json file is provided.
+    *  If the provided resource does not exist then Client fails with path is not valid error.
+    *  If provided resource value is changed from an int to a file  then the image resource from the file is attached.
+    *  If provided resource value is changed from a file to an int then image revision is attached.
 `
 )
 
@@ -855,6 +865,17 @@ func (r *applicationResource) Update(ctx context.Context, req resource.UpdateReq
 				updateApplicationInput.Resources[k] = v
 			}
 		}
+		// Resources are removed
+		if len(planResourceMap) == 0 && len(stateResourceMap) != 0 {
+			for k := range stateResourceMap {
+				if updateApplicationInput.Resources == nil {
+					// initialize the resources
+					updateApplicationInput.Resources = make(map[string]string)
+					// Set resource revision
+					updateApplicationInput.Resources[k] = "0"
+				}
+			}
+		}
 	}
 
 	if !plan.Constraints.Equal(state.Constraints) {