Add mongodb updateone, findone and findmany functions

db/mongo.go

@@ -72,6 +72,66 @@ func (c *mongoCollection) InsertOne(ctx context.Context, key interface{}, data i
 	return nil
 }
 
+// inserts or updates one entry with given key and data to the collection
+// acts based on the flag passed for upsert
+// returns errors if entry not found while upsert flag is false or if
+// there is a connection error with the database server
+func (c *mongoCollection) UpdateOne(ctx context.Context, key interface{}, data interface{}, upsert bool) error {
+	if data == nil {
+		return errors.Wrap(errors.InvalidArgument, "db Insert error: No data to store")
+	}
+	if key == nil {
+		return errors.Wrap(errors.InvalidArgument, "db Insert error: No Key specified to store")
+	}
+
+	opts := options.Update().SetUpsert(upsert)
+	resp, err := c.col.UpdateOne(
+		ctx,
+		bson.M{"_id": key},
+		bson.D{
+			{Key: "$set", Value: data},
+		},
+		opts)
+
+	if err != nil {
+		return err
+	}
+
+	// check there should be at least one entry in matched count
+	// or upserted count to not return an error here
+	if resp.MatchedCount != 0 && resp.UpsertedCount != 0 {
+		return errors.Wrap(errors.NotFound, "No Document found")
+	}
+
+	return nil
+}
+
+// Find one entry from the store collection for the given key, where the data
+// value is returned based on the object type passed to it
+func (c *mongoCollection) FindOne(ctx context.Context, key interface{}, data interface{}) error {
+	resp := c.col.FindOne(ctx, bson.M{"_id": key})
+	// decode the value returned by the mongodb client into the data
+	// object passed by the caller
+	if err := resp.Decode(data); err != nil {
+		// TODO(prabhjot) might have to identify not found error
+		return err
+	}
+	return nil
+}
+
+// Find multiple entries from the store collection for the given filter, where the data
+// value is returned as a list based on the object type passed to it
+func (c *mongoCollection) FindMany(ctx context.Context, filter interface{}, data interface{}) error {
+	cursor, err := c.col.Find(ctx, filter)
+	if err != nil {
+		return err
+	}
+	if err = cursor.All(ctx, data); err != nil {
+		return err
+	}
+	return nil
+}
+
 // remove one entry from the collection matching the given key
 func (c *mongoCollection) DeleteOne(ctx context.Context, key interface{}) error {
 	resp, err := c.col.DeleteOne(ctx, bson.M{"_id": key})

db/mongo_test.go

@@ -12,8 +12,13 @@ type MyKey struct {
 	Name string
 }
 
+type InternaData struct {
+	Test string
+}
+
 type MyData struct {
 	Desc string
+	Val  *InternaData
 }
 
 func Test_ClientConnection(t *testing.T) {
@@ -46,12 +51,35 @@ func Test_ClientConnection(t *testing.T) {
 		}
 		data := &MyData{
 			Desc: "sample-description",
+			Val: &InternaData{
+				Test: "abc",
+			},
 		}
+
 		err = col.InsertOne(context.Background(), key, data)
 		if err != nil {
 			t.Errorf("failed to insert an entry to collection Error: %s", err)
 		}
 
+		val := &MyData{}
+		err = col.FindOne(context.Background(), key, val)
+		if err != nil {
+			t.Errorf("failed to find the entry Error: %s", err)
+		}
+
+		data.Desc = "new description"
+		data.Val.Test = "xyz"
+		err = col.UpdateOne(context.Background(), key, data, false)
+		if err != nil {
+			t.Errorf("failed to update an entry to collection Error: %s", err)
+		}
+
+		val = &MyData{}
+		err = col.FindOne(context.Background(), key, val)
+		if err != nil {
+			t.Errorf("failed to find the entry Error: %s", err)
+		}
+
 		err = col.DeleteOne(context.Background(), key)
 		if err != nil {
 			t.Errorf("failed to delete entry using key Error: %s", err)
@@ -61,6 +89,16 @@ func Test_ClientConnection(t *testing.T) {
 		if err == nil {
 			t.Errorf("attemptting delete on already deleted entry, but didn't receive expected error")
 		}
+
+		err = col.UpdateOne(context.Background(), key, data, true)
+		if err != nil {
+			t.Errorf("failed to update an entry to collection Error: %s", err)
+		}
+
+		err = col.DeleteOne(context.Background(), key)
+		if err != nil {
+			t.Errorf("failed to delete entry using key Error: %s", err)
+		}
 	})
 
 	t.Run("InValid_Port", func(t *testing.T) {

db/store.go

@@ -15,6 +15,19 @@ type StoreCollection interface {
 	// insert one entry to the collection for the given key and data
 	InsertOne(ctx context.Context, key interface{}, data interface{}) error
 
+	// update one entry in the collection for the given key and data
+	// if upsert flag is set, it would insert an entry if it doesn't
+	// exist while updating
+	UpdateOne(ctx context.Context, key interface{}, data interface{}, upsert bool) error
+
+	// Find one entry from the store collection for the given key, where the data
+	// value is returned based on the object type passed to it
+	FindOne(ctx context.Context, key interface{}, data interface{}) error
+
+	// Find multiple entries from the store collection for the given filter, where the data
+	// value is returned as a list based on the object type passed to it
+	FindMany(ctx context.Context, filter interface{}, data interface{}) error
+
 	// remove one entry from the collection matching the given key
 	DeleteOne(ctx context.Context, key interface{}) error
 }