cmd: Handle case when deployment template does not include resource (#205)

Fixes a bug where the application would panic if it could not find the 
desired resource kind in the deployment template.

Author: karencfv

pkg/deployment/depresource/apm.go

@@ -18,6 +18,8 @@
 package depresource
 
 import (
+	"fmt"
+
 	"github.com/elastic/cloud-sdk-go/pkg/api"
 	"github.com/elastic/cloud-sdk-go/pkg/client/platform_configuration_templates"
 	"github.com/elastic/cloud-sdk-go/pkg/models"
@@ -56,6 +58,11 @@ func NewApm(params NewStateless) (*models.ApmPayload, error) {
 		return nil, api.UnwrapError(err)
 	}
 
+	if res.Payload.ClusterTemplate.Apm == nil {
+		return nil, fmt.Errorf("deployment: the %s template is not configured for APM. Please use another template if you wish to start APM instances",
+			params.TemplateID)
+	}
+
 	var clusterTopology = res.Payload.ClusterTemplate.Apm.Plan.ClusterTopology
 	var topology = models.ApmTopologyElement{Size: new(models.TopologySize)}
 	if len(clusterTopology) > 0 {

pkg/deployment/depresource/apm_test.go

@@ -54,6 +54,15 @@ var apmTemplateResponse = models.DeploymentTemplateInfo{
 	},
 }
 
+var crossClusterTemplateResponse = models.DeploymentTemplateInfo{
+	ID: "cross-cluster-search",
+	ClusterTemplate: &models.DeploymentTemplateDefinitionRequest{
+		Plan: &models.ElasticsearchClusterPlan{
+			ClusterTopology: defaultESTopologies,
+		},
+	},
+}
+
 func TestNewApm(t *testing.T) {
 	var internalError = models.BasicFailedReply{
 		Errors: []*models.BasicFailedReplyElement{
@@ -139,6 +148,18 @@ func TestNewApm(t *testing.T) {
 			}},
 			err: errors.New(string(internalErrorBytes)),
 		},
+		{
+			name: "obtains the deployment template but it's an invalid template for appsearch",
+			args: args{params: NewStateless{
+				DeploymentID: util.ValidClusterID,
+				API: api.NewMock(
+					mock.New200Response(mock.NewStructBody(getResponse)),
+					mock.New200Response(mock.NewStructBody(crossClusterTemplateResponse)),
+				),
+				Region: "ece-region",
+			}},
+			err: errors.New("deployment: the an ID template is not configured for APM. Please use another template if you wish to start APM instances"),
+		},
 		{
 			name: "succeeds with no argument override",
 			args: args{params: NewStateless{

pkg/deployment/depresource/appsearch.go

@@ -18,6 +18,8 @@
 package depresource
 
 import (
+	"fmt"
+
 	"github.com/elastic/cloud-sdk-go/pkg/api"
 	"github.com/elastic/cloud-sdk-go/pkg/client/platform_configuration_templates"
 	"github.com/elastic/cloud-sdk-go/pkg/models"
@@ -56,6 +58,11 @@ func NewAppSearch(params NewStateless) (*models.AppSearchPayload, error) {
 		return nil, api.UnwrapError(err)
 	}
 
+	if res.Payload.ClusterTemplate.Appsearch == nil {
+		return nil, fmt.Errorf("deployment: the %s template is not configured for AppSearch. Please use another template if you wish to start AppSearch instances",
+			params.TemplateID)
+	}
+
 	var clusterTopology = res.Payload.ClusterTemplate.Appsearch.Plan.ClusterTopology
 	var topology = models.AppSearchTopologyElement{Size: new(models.TopologySize)}
 	if len(clusterTopology) > 0 {

pkg/deployment/depresource/appsearch_test.go

@@ -33,7 +33,7 @@ import (
 )
 
 var appsearchTemplateResponse = models.DeploymentTemplateInfo{
-	ID: "default",
+	ID: "default.appsearch",
 	ClusterTemplate: &models.DeploymentTemplateDefinitionRequest{
 		Appsearch: &models.CreateAppSearchRequest{
 			Plan: &models.AppSearchPlan{
@@ -54,6 +54,15 @@ var appsearchTemplateResponse = models.DeploymentTemplateInfo{
 	},
 }
 
+var defaultTemplateResponse = models.DeploymentTemplateInfo{
+	ID: "default",
+	ClusterTemplate: &models.DeploymentTemplateDefinitionRequest{
+		Plan: &models.ElasticsearchClusterPlan{
+			ClusterTopology: defaultESTopologies,
+		},
+	},
+}
+
 func TestNewAppSearch(t *testing.T) {
 	var internalError = models.BasicFailedReply{
 		Errors: []*models.BasicFailedReplyElement{
@@ -139,6 +148,18 @@ func TestNewAppSearch(t *testing.T) {
 			}},
 			err: errors.New(string(internalErrorBytes)),
 		},
+		{
+			name: "obtains the deployment template but it's an invalid template for appsearch",
+			args: args{params: NewStateless{
+				DeploymentID: util.ValidClusterID,
+				API: api.NewMock(
+					mock.New200Response(mock.NewStructBody(getResponse)),
+					mock.New200Response(mock.NewStructBody(defaultTemplateResponse)),
+				),
+				Region: "ece-region",
+			}},
+			err: errors.New("deployment: the an ID template is not configured for AppSearch. Please use another template if you wish to start AppSearch instances"),
+		},
 		{
 			name: "succeeds with no argument override",
 			args: args{params: NewStateless{