Add function to list datasources (#1287)

* Add function to list datasources

* Sort datasources in ascending order and return in listDatasources

* Fix lint error

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

2 files changed, 21 insertions, 0 deletions

diff --git a/data/datasource.go b/data/datasource.go
index 5f684a4c..79c29e5f 100644
--- a/data/datasource.go
+++ b/data/datasource.go
@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/url"
 	"path/filepath"
+	"sort"
 	"strings"
 
 	"github.com/spf13/afero"
@@ -382,3 +383,13 @@ func (d *Data) readSource(ctx context.Context, source *Source, args ...string) (
 	d.cache[cacheKey] = data
 	return data, nil
 }
+
+// Show all datasources  -
+func (d *Data) ListDatasources() []string {
+	datasources := make([]string, 0, len(d.Sources))
+	for source := range d.Sources {
+		datasources = append(datasources, source)
+	}
+	sort.Strings(datasources)
+	return datasources
+}
diff --git a/data/datasource_test.go b/data/datasource_test.go
index 4cffc763..aadcef0e 100644
--- a/data/datasource_test.go
+++ b/data/datasource_test.go
@@ -412,3 +412,13 @@ func TestFromConfig(t *testing.T) {
 	}
 	assert.EqualValues(t, expected, FromConfig(ctx, cfg))
 }
+
+func TestListDatasources(t *testing.T) {
+	sources := map[string]*Source{
+		"foo": {Alias: "foo"},
+		"bar": {Alias: "bar"},
+	}
+	data := &Data{Sources: sources}
+
+	assert.Equal(t, []string{"bar", "foo"}, data.ListDatasources())
+}