gofr-dev/gofr · warning

%w: %s

Error message

%w: %s

What it means

In the DynamoDB KV client, Get wraps errKeyNotFound with the offending key using fmt.Errorf("%w: %s", errKeyNotFound, key) when the item exists but has no 'value' attribute, or more broadly when the key is absent. Because %w is used, errors.Is(err, errKeyNotFound) still matches. The message form is 'key not found: <key>'.

Source

Thrown at pkg/gofr/datasource/kv-store/dynamodb/dynamo.go:174

	out, err := c.db.GetItem(ctx, input)
	if err != nil {
		c.logger.Errorf("error while fetching data for key: %v, error: %v", key, err)
		return "", err
	}

	if out.Item == nil {
		return "", errKeyNotFound
	}

	// Look for a "value" field that contains the JSON string
	if valueField, exists := out.Item["value"]; exists {
		if stringValue, ok := valueField.(*types.AttributeValueMemberS); ok {
			return stringValue.Value, nil
		}
	}

	// If no "value" field exists, return key not found error
	return "", fmt.Errorf("%w: %s", errKeyNotFound, key)
}

func (c *Client) Set(ctx context.Context, key, value string) error {
	if !c.connected {
		return errClientNotConnected
	}

	span := c.addTrace(ctx, "set", key)
	defer c.sendOperationsStats(time.Now(), "SET", "set", span, key)

	// Store the value as a string in the "value" field
	item := map[string]types.AttributeValue{
		c.configs.PartitionKeyName: &types.AttributeValueMemberS{Value: key},
		"value":                    &types.AttributeValueMemberS{Value: value},
	}

	input := &dynamodb.PutItemInput{
		TableName: aws.String(c.configs.Table),

View on GitHub (pinned to 187eb24962)

Solutions

1. Check errors.Is(err, errKeyNotFound) and treat as a miss rather than a hard failure
2. Ensure writers use this client's Set so items contain the 'value' attribute
3. Verify Configs.Table targets the intended table
4. Inspect the key echoed in the message for typos/casing mismatches

Example fix

// before
v, err := store.Get(ctx, k)
if err != nil { log.Fatal(err) }
// after
v, err := store.Get(ctx, k)
if errors.Is(err, dynamodb.ErrKeyNotFound) { v, err = loadDefault(k), nil }

// check key before calling Get
if key == "" { return errors.New("empty key") }
// ensure writers use Set so items carry the 'value' attribute

func IsKeyNotFound(err error) bool { return errors.Is(err, dynamodb.ErrKeyNotFound) }

v, err := store.Get(ctx, key)
if errors.Is(err, dynamodb.ErrKeyNotFound) {
    log.Printf("miss: %s", key) // message contains key
    return handleMiss(key)
}
if err != nil { return err }

When it happens

Trigger: Client.Get on a key whose DynamoDB item lacks a 'value' attribute (e.g. items written by other tools or with different attribute names), or on keys that do not exist in the table.

Common situations: Table populated by another application or migration using different attribute names, partially written items, wrong table selected, keys deleted concurrently.

Related errors

• key not found
• client not connected, call Connect() first
• status down
• failed to marshal value to JSON: %w
• failed to unmarshal JSON: %w

AI-assisted analysis of gofr-dev/gofr@187eb24962 (2026-09-01). Data as JSON: /api/errors/ba6d4f7e3ba9182d. Report an issue: GitHub.