feat(go-sdk): Helper for retrieving SLI resources (#541)

* implementation of config and resource client (from dt service)

Signed-off-by: warber <bernd.warmuth@dynatrace.com>

* removed unneeded code and provided tests for resource client

Signed-off-by: warber <bernd.warmuth@dynatrace.com>

* cleanup

Signed-off-by: warber <bernd.warmuth@dynatrace.com>

* renaming

Signed-off-by: warber <bernd.warmuth@dynatrace.com>

Signed-off-by: warber <bernd.warmuth@dynatrace.com>

pkg/api/utils/v2/resourceUtils.go

@@ -66,6 +66,7 @@ type ResourcesCreateResourceOptions struct {
 	URIOptions []URIOption
 }
 
+//go:generate moq -pkg utils_mock -skip-ensure -out ./fake/resources_handler_mock.go . ResourcesInterface
 type ResourcesInterface interface {
 	// CreateResources creates a resource for the specified entity.
 	CreateResources(ctx context.Context, project string, stage string, service string, resources []*models.Resource, opts ResourcesCreateResourcesOptions) (*models.EventContext, *models.Error)

pkg/sdk/helpers/resource_client.go

@@ -0,0 +1,279 @@
+package keptn
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	keptnmodels "github.com/keptn/go-utils/pkg/api/models"
+	v2 "github.com/keptn/go-utils/pkg/api/utils/v2"
+	log "github.com/sirupsen/logrus"
+)
+
+const projectFieldName = "project"
+const stageFieldName = "stage"
+const serviceFieldName = "service"
+const resourceURIFieldName = "resourceURI"
+
+// ResourceClientInterface defines the methods for interacting with resources of Keptn's configuration service.
+type ResourceClientInterface interface {
+	// GetResource tries to find the first instance of a given resource on service, stage or project level.
+	GetResource(ctx context.Context, project string, stage string, service string, resourceURI string) (string, error)
+
+	// GetProjectResource tries to retrieve a resource on project level.
+	GetProjectResource(ctx context.Context, project string, resourceURI string) (string, error)
+
+	// GetStageResource tries to retrieve a resource on stage level.
+	GetStageResource(ctx context.Context, project string, stage string, resourceURI string) (string, error)
+
+	// GetServiceResource tries to retrieve a resource on service level.
+	GetServiceResource(ctx context.Context, project string, stage string, service string, resourceURI string) (string, error)
+
+	// UploadResource tries to upload a resource.
+	UploadResource(ctx context.Context, contentToUpload []byte, remoteResourceURI string, project string, stage string, service string) error
+}
+
+// ResourceError represents an error for a resource that was not found.
+type ResourceError struct {
+	uri     string
+	project string
+	stage   string
+	service string
+}
+
+// ResourceNotFoundError represents an error for a resource that was not found.
+type ResourceNotFoundError ResourceError
+
+// Error returns a string representation of this error
+func (e *ResourceNotFoundError) Error() string {
+	return fmt.Sprintf("could not find resource: '%s' %s", e.uri, getLocation(e.service, e.stage, e.project))
+}
+
+// ResourceEmptyError represents an error for a resource that was found, but is empty.
+type ResourceEmptyError ResourceError
+
+// Error returns a string representation of this error
+func (e *ResourceEmptyError) Error() string {
+	return fmt.Sprintf("found resource: '%s' %s, but it is empty", e.uri, getLocation(e.service, e.stage, e.project))
+}
+
+// ResourceUploadFailedError represents an error for a resource that could not be uploaded.
+type ResourceUploadFailedError struct {
+	ResourceError
+	message string
+}
+
+// Error returns a string representation of this error.
+func (e *ResourceUploadFailedError) Error() string {
+	return fmt.Sprintf("could not upload resource: '%s' %s: %s", e.uri, getLocation(e.service, e.stage, e.project), e.message)
+}
+
+// ResourceRetrievalFailedError represents an error for a resource that could not be retrieved because of an error.
+type ResourceRetrievalFailedError struct {
+	ResourceError
+	cause error
+}
+
+// Error returns a string representation of this error.
+func (e *ResourceRetrievalFailedError) Error() string {
+	return fmt.Sprintf("could not retrieve resource: '%s' %s: %v", e.uri, getLocation(e.service, e.stage, e.project), e.cause)
+}
+
+// Unwrap returns the cause of the ResourceRetrievalFailedError.
+func (e *ResourceRetrievalFailedError) Unwrap() error {
+	return e.cause
+}
+
+func getLocation(service string, stage string, project string) string {
+	var location string
+
+	if service != "" {
+		location += fmt.Sprintf(" for service '%s'", service)
+	}
+	if stage != "" {
+		location += fmt.Sprintf(" at stage '%s'", stage)
+	}
+	if project != "" {
+		location += fmt.Sprintf(" of project '%s'", project)
+	}
+
+	return strings.TrimLeft(location, " ")
+}
+
+// ResourceHelper is the default implementation for the ResourceClientInterface using a Keptn api.ResourcesV1Interface.
+type ResourceHelper struct {
+	client v2.ResourcesInterface
+}
+
+// NewResourceHelper creates a new ResourceHelper using a api.ResourcesV1Interface.
+func NewResourceHelper(client v2.ResourcesInterface) *ResourceHelper {
+	return &ResourceHelper{
+		client: client,
+	}
+}
+
+// GetResource tries to find the first instance of a given resource on service, stage or project level.
+func (rc *ResourceHelper) GetResource(ctx context.Context, project string, stage string, service string, resourceURI string) (string, error) {
+	var rnfErrorType *ResourceNotFoundError
+	if project != "" && stage != "" && service != "" {
+		keptnResourceContent, err := rc.GetServiceResource(ctx, project, stage, service, resourceURI)
+		if errors.As(err, &rnfErrorType) {
+			log.WithFields(
+				log.Fields{
+					projectFieldName:     project,
+					stageFieldName:       stage,
+					serviceFieldName:     service,
+					resourceURIFieldName: resourceURI,
+				}).Debug("Resource not available for service")
+		} else if err != nil {
+			return "", err
+		} else {
+			log.WithFields(
+				log.Fields{
+					projectFieldName:     project,
+					stageFieldName:       stage,
+					serviceFieldName:     service,
+					resourceURIFieldName: resourceURI,
+				}).Info("Found resource for service")
+			return keptnResourceContent, nil
+		}
+	}
+
+	if project != "" && stage != "" {
+		keptnResourceContent, err := rc.GetStageResource(ctx, project, stage, resourceURI)
+		if errors.As(err, &rnfErrorType) {
+			log.WithFields(
+				log.Fields{
+					projectFieldName:     project,
+					stageFieldName:       stage,
+					resourceURIFieldName: resourceURI,
+				}).Debug("Resource not available for stage")
+		} else if err != nil {
+			return "", err
+		} else {
+			log.WithFields(
+				log.Fields{
+					projectFieldName:     project,
+					stageFieldName:       stage,
+					resourceURIFieldName: resourceURI,
+				}).Info("Found resource for stage")
+			return keptnResourceContent, nil
+		}
+	}
+
+	if project != "" {
+		keptnResourceContent, err := rc.GetProjectResource(ctx, project, resourceURI)
+		if errors.As(err, &rnfErrorType) {
+			log.WithFields(
+				log.Fields{
+					projectFieldName:     project,
+					resourceURIFieldName: resourceURI,
+				}).Debug("Resource not available for project")
+		} else if err != nil {
+			return "", err
+		} else {
+			log.WithFields(
+				log.Fields{projectFieldName: project,
+					resourceURIFieldName: resourceURI,
+				}).Info("Found resource for project")
+			return keptnResourceContent, nil
+		}
+	}
+
+	log.WithField(resourceURIFieldName, resourceURI).Info("Resource not found")
+	return "", &ResourceNotFoundError{uri: resourceURI, project: project, stage: stage, service: service}
+}
+
+// GetServiceResource tries to retrieve a resource on service level.
+func (rc *ResourceHelper) GetServiceResource(ctx context.Context, project string, stage string, service string, resourceURI string) (string, error) {
+	return getResourceByFunc(
+		func() (*keptnmodels.Resource, error) {
+			return rc.client.GetResource(ctx,
+				*v2.NewResourceScope().Project(project).Stage(stage).Service(service).Resource(resourceURI),
+				v2.ResourcesGetResourceOptions{})
+		},
+		func() *ResourceNotFoundError {
+			return &ResourceNotFoundError{uri: resourceURI, project: project, stage: stage, service: service}
+		},
+		func(cause error) *ResourceRetrievalFailedError {
+			return &ResourceRetrievalFailedError{ResourceError{uri: resourceURI, project: project, stage: stage, service: service}, cause}
+		},
+		func() *ResourceEmptyError {
+			return &ResourceEmptyError{uri: resourceURI, project: project, stage: stage, service: service}
+		})
+}
+
+// GetStageResource tries to retrieve a resource on stage level.
+func (rc *ResourceHelper) GetStageResource(ctx context.Context, project string, stage string, resourceURI string) (string, error) {
+	return getResourceByFunc(
+		func() (*keptnmodels.Resource, error) {
+			return rc.client.GetResource(ctx,
+				*v2.NewResourceScope().Project(project).Stage(stage).Resource(resourceURI),
+				v2.ResourcesGetResourceOptions{})
+		},
+		func() *ResourceNotFoundError {
+			return &ResourceNotFoundError{uri: resourceURI, project: project, stage: stage}
+		},
+		func(cause error) *ResourceRetrievalFailedError {
+			return &ResourceRetrievalFailedError{ResourceError{uri: resourceURI, project: project, stage: stage}, cause}
+		},
+		func() *ResourceEmptyError {
+			return &ResourceEmptyError{uri: resourceURI, project: project, stage: stage}
+		})
+}
+
+// GetProjectResource tries to retrieve a resource on project level.
+func (rc *ResourceHelper) GetProjectResource(ctx context.Context, project string, resourceURI string) (string, error) {
+	return getResourceByFunc(
+		func() (*keptnmodels.Resource, error) {
+			return rc.client.GetResource(ctx,
+				*v2.NewResourceScope().Project(project).Resource(resourceURI),
+				v2.ResourcesGetResourceOptions{})
+		},
+		func() *ResourceNotFoundError { return &ResourceNotFoundError{uri: resourceURI, project: project} },
+		func(cause error) *ResourceRetrievalFailedError {
+			return &ResourceRetrievalFailedError{ResourceError{uri: resourceURI, project: project}, cause}
+		},
+		func() *ResourceEmptyError { return &ResourceEmptyError{uri: resourceURI, project: project} })
+}
+
+func getResourceByFunc(
+	resFunc func() (*keptnmodels.Resource, error),
+	rnfErrFunc func() *ResourceNotFoundError,
+	rrfErrFunc func(cause error) *ResourceRetrievalFailedError,
+	reErrFunc func() *ResourceEmptyError) (string, error) {
+	resource, err := resFunc()
+	if err != nil {
+		if err == v2.ResourceNotFoundError {
+			return "", rnfErrFunc()
+		}
+
+		return "", rrfErrFunc(err)
+	}
+	if resource.ResourceContent == "" {
+		return "", reErrFunc()
+	}
+
+	return resource.ResourceContent, nil
+}
+
+// UploadResource tries to upload a resource.
+func (rc *ResourceHelper) UploadResource(ctx context.Context, contentToUpload []byte, remoteResourceURI string, project string, stage string, service string) error {
+	resources := []*keptnmodels.Resource{{ResourceContent: string(contentToUpload), ResourceURI: &remoteResourceURI}}
+	_, err := rc.client.CreateResources(ctx, project, stage, service, resources, v2.ResourcesCreateResourcesOptions{})
+	if err != nil {
+		return &ResourceUploadFailedError{
+			ResourceError{
+				uri:     remoteResourceURI,
+				project: project,
+				stage:   stage,
+				service: service,
+			},
+			err.GetMessage(),
+		}
+	}
+
+	log.WithField("remoteResourceURI", remoteResourceURI).Info("Uploaded file")
+	return nil
+}