DISPATCH-2262 - Added an app-level (above Proton) heartbeat feature… #1396
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…hat can be used when the Proton heartbeats aren't in effect.
| // | ||
| qdr_terminus_t *target = qdr_terminus(0); | ||
| qdr_terminus_set_address(target, QD_TERMINUS_HEARTBEAT); | ||
| client->endpoint = qdrc_endpoint_create_link_CT(client->core, client->edge_conn, QD_OUTGOING, |
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Not for this patch, but it probably makes sense to assign a priority to created endpoint links. qdrc_endpoint_create_link_CT() creates all links with priority 4. It probably makes sense to send these heartbeats at a higher priority.
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| fld = qd_compose(QD_PERFORMATIVE_PROPERTIES, fld); | ||
| qd_compose_start_list(fld); | ||
| qd_compose_insert_int(fld, client->next_msg_id); // message-id |
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Does this really insert an int? Since int isnt one of the message-id types (string, uuid, binary, ulong).
| qd_composed_field_t *fld = qd_compose(QD_PERFORMATIVE_HEADER, 0); | ||
| qd_compose_start_list(fld); | ||
| qd_compose_insert_bool(fld, 0); // durable | ||
| qd_compose_end_list(fld); |
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Why not just omit the header? It would be equivalent since durable is false by default.
| qd_composed_field_t *body = qd_compose(QD_PERFORMATIVE_BODY_AMQP_VALUE, 0); | ||
| qd_compose_insert_null(body); |
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Rather than specify a [non-unique] message-id, and also sending an amqp-value+null body, why not just omit the properties section as well and have the amqp-value section contain the count?
Less to encode and smaller to send. Doesnt seem like it is even decoded actually.
…that can be used when the Proton heartbeats aren't in effect.
This is a workaround for a possible Proton heartbeat issue.
The heartbeat facility can be used by any endpoint that connects to the router by creating a sender to address '_$qd.edge_heartbeat'. Once this sender is attached, messages must be sent along the link to keep the connection alive. The connection will be closed by the connected router after 8 seconds of no traffic on the heartbeat link.
In this PR, edge routers use this facility to protect their uplink connections to interior routers.
Question: should the timeout be configurable?