bondy.error.bad_gateway

When an upstream service that Bondy forwards to gives no usable answer.

Description

Three components raise this error. Each one sends it in a different shape.

The forward action of an API Gateway Specification raises it when a request to the upstream HTTP host fails and the failure is not a timeout. Examples are a refused connection and a host name that does not resolve. The original HTTP caller receives 502 Bad Gateway. The response body is the standard error payload as JSON. message names the upstream URL, and details.url holds it. The underlying connection error goes to the log only. An upstream that does not respond in time gives bondy.error.gateway_timeout (504) instead. An upstream that answers with any status does not give this error: the action's on_result or on_error response applies.

The HTTP connector raises it to a WAMP caller in two cases:

• The connection to the upstream fails, and the cause is neither a timeout nor a pool that is down.
• The upstream answers with a 3xx status, or with a 5xx status other than 504. A 503 answer is one of these cases.

A connect, pool checkout or response that outlasts the procedure's timeout gives bondy.error.gateway_timeout. A 504 or 408 answer from the upstream gives wamp.error.timeout. A connector whose connection pool is down gives wamp.error.unavailable.

A procedure that Bondy projects from an MCP upstream raises it when the upstream MCP session is not available or the upstream MCP server cannot be reached.

Positional Results

None. The HTTP connector and the MCP upstream send an ERROR with no positional arguments. The forward action answers over HTTP, which has no positional arguments.

Keyword Results

The HTTP connector and the MCP upstream send the keyword arguments below. They do not send the standard error payload.

statusinteger

HTTP connector only. 502 when the upstream sent no response. Otherwise the status the upstream answered with.

messagestring

Present when the upstream sent no response. The HTTP connector sends Upstream connection failed. The MCP upstream sends Upstream MCP session unavailable or Upstream MCP server unreachable.

bodyany

HTTP connector only, when the upstream answered. The response body, decoded when it is JSON and as received otherwise.