SigNoz/signoz · error · model.ApiError

cannot parse the request body: %v

Error message

cannot parse the request body: %v

What it means

ParseQueryRangeParams failed to JSON-decode the POST body into v3.QueryRangeParamsV3, returning ErrorBadData. Any malformed JSON or schema mismatch (wrong types, unknown enum values for panelType, etc.) triggers it.

Source

Thrown at pkg/query-service/app/parser.go:761

			IsSelectAll: true,
			FieldType:   "scalar",
		})
	}
	transformer := chVariables.NewQueryTransformer(query, varsForTransform)
	transformedQuery, err := transformer.Transform()
	if err != nil {
		slog.Warn("failed to transform clickhouse query", "query", query, signozerrors.Attr(err))
	}
	slog.Info("transformed clickhouse query", "transformed_query", transformedQuery, "original_query", query)
}

func ParseQueryRangeParams(r *http.Request) (*v3.QueryRangeParamsV3, *model.ApiError) {

	var queryRangeParams *v3.QueryRangeParamsV3

	// parse the request body
	if err := json.NewDecoder(r.Body).Decode(&queryRangeParams); err != nil {
		return nil, &model.ApiError{Typ: model.ErrorBadData, Err: fmt.Errorf("cannot parse the request body: %v", err)}
	}

	// sanitize the request body
	queryRangeParams.CompositeQuery.Sanitize()

	// validate the request body
	if err := validateQueryRangeParamsV3(queryRangeParams); err != nil {
		return nil, &model.ApiError{Typ: model.ErrorBadData, Err: err}
	}

	// Clamp the top-level Step for PromQL
	if queryRangeParams.CompositeQuery.QueryType == v3.QueryTypePromQL {
		if minStep := common.MinAllowedStepInterval(queryRangeParams.Start, queryRangeParams.End); queryRangeParams.Step < minStep {
			queryRangeParams.Step = minStep
		}
	}

	// prepare the variables for the corresponding query type

View on GitHub (pinned to 5069bf80b0)

Solutions

1. Validate the body against the QueryRangeParamsV3 schema (start/end in microseconds, compositeQuery with panelType and queries)
2. Send Content-Type: application/json and a well-formed body
3. Capture the exact body and decode it locally with json.Decoder to see the field-level error

Example fix

// before
curl -X POST /api/v3/query_range -d '{"start": "now"}'
// after
curl -X POST /api/v3/query_range -H 'Content-Type: application/json' -d '{"start":1700000000000000,"end":1700003600000000,"compositeQuery":{"panelType":"graph","builderQueries":{}}}'

var p v3.QueryRangeParamsV3
if err := json.NewDecoder(bytes.NewReader(body)).Decode(&p); err != nil { return fmt.Errorf("body does not match QueryRangeParamsV3: %v", err) }

On 400 with 'cannot parse the request body', log the raw body and the wrapped json error to identify the exact offending field.

When it happens

Trigger: POST /api/v3/query_range with invalid JSON, wrong field types (e.g. start as string when number expected), or a compositeQuery shape that doesn't match the struct.

Common situations: Manually crafting API payloads instead of using the UI; version drift where the payload schema changed; proxies stripping or truncating the body; sending an empty body.

Related errors

• invalid request body: %v
• error decoding request: %v
• couldn't JSON decode existingFilter: %w
• error while getting ttl. ttl type should be metrics|traces,
• ErrorID missing from params

AI-assisted analysis of SigNoz/signoz@5069bf80b0 (2026-08-28). Data as JSON: /api/errors/87adf26ceaed7781. Report an issue: GitHub.