fix(variants): return error for variants overview when ES is down

src/api/mvc/data-types/main.go

@@ -25,8 +25,15 @@ func GetDataTypes(c echo.Context) error {
 
 	// accumulate number of variants associated with each
 	// sampleId fetched from the variants overview
-	// TODO: refactor to handle errors better
-	resultsMap := variantService.GetVariantsOverview(es, cfg)
+	resultsMap, err := variantService.GetVariantsOverview(es, cfg)
+
+	if err != nil {
+		// Could not talk to Elasticsearch, return an error
+		return c.JSON(http.StatusInternalServerError, map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
 	variantDataTypeJson["count"] = sumAllValues(resultsMap["sampleIDs"])
 
 	// Data types are basically stand-ins for schema blocks

src/api/mvc/variants/main.go

@@ -434,8 +434,14 @@ func GetVariantsOverview(c echo.Context) error {
 	es := c.(*contexts.GohanContext).Es7Client
 	cfg := c.(*contexts.GohanContext).Config
 
-	// TODO: refactor to handle errors better
-	resultsMap := variantService.GetVariantsOverview(es, cfg)
+	resultsMap, err := variantService.GetVariantsOverview(es, cfg)
+
+	if err != nil {
+		// Could not talk to Elasticsearch, return an error
+		return c.JSON(http.StatusInternalServerError, map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
 
 	return c.JSON(http.StatusOK, resultsMap)
 }

src/api/services/variants/main.go

@@ -1,6 +1,7 @@
 package variantsService
 
 import (
+	"errors"
 	"fmt"
 	"gohan/api/models"
 	esRepo "gohan/api/repositories/elasticsearch"
@@ -23,7 +24,7 @@ func NewVariantService(cfg *models.Config) *VariantService {
 	return vs
 }
 
-func GetVariantsOverview(es *elasticsearch.Client, cfg *models.Config) map[string]interface{} {
+func GetVariantsOverview(es *elasticsearch.Client, cfg *models.Config) (map[string]interface{}, error) {
 	resultsMap := map[string]interface{}{}
 	resultsMux := sync.RWMutex{}
 
@@ -70,6 +71,12 @@ func GetVariantsOverview(es *elasticsearch.Client, cfg *models.Config) map[strin
 		resultsMux.Unlock()
 	}
 
+	// First, make sure the ES cluster is running - otherwise this will hang for a long time
+	_, err := es.Ping()
+	if err != nil {
+		return nil, errors.New("could not contact Elasticsearch - make sure it's running")
+	}
+
 	// get distribution of chromosomes
 	wg.Add(1)
 	go callGetBucketsByKeyword("chromosomes", "chrom.keyword", &wg)
@@ -92,5 +99,5 @@ func GetVariantsOverview(es *elasticsearch.Client, cfg *models.Config) map[strin
 
 	wg.Wait()
 
-	return resultsMap
+	return resultsMap, nil
 }