SERVICE-DISCOVERY-API

Timeline

• 2026-05-07 — 48600b5 — Migrate logos-messaging/specs into docs/messaging/ (#315)
• 2026-05-05 — ea3f24b — New logos service discovery API (#309)

Abstract

TODO

Motivation

TODO

Semantic

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119.

API Specification

The aim is to define an API that is compatible with most discovery protocols that supports service-specific discovery, maintaining similar function signatures even if the underlying protocol differs.

The API is defined in the form of C-style bindings. However, this simply serves to illustrate the exposed functions and can be adapted into the conventions of any strongly typed language. Although unspecified in the API below, all functions SHOULD return an error result type appropriate to the implementation language.

Type Definitions

typedef struct {
    const uint8_t* bytes;
    size_t   len;
} Advertisement;

typedef struct {
    const Advertisement* ads;
    size_t                  len;
} AdvertisementList;

start()

Start the discovery protocol, including all tasks related to bootstrapping and maintenance of the underlying discovery protocol (such as initialising the routing table).

stop()

Stop the discovery protocol, including all tasks related to maintenance of the underlying discovery protocol (such as advertising or discovery loops).

start_advertising(const char* service_id, const Advertisement* advertisement)

Start advertising the encoded advertisement against any service encoded as a service_id string. For peer discovery, the node MUST encode sufficient connection information in the Advertisement for discoverers to connect to it.

stop_advertising(const char* service_id)

Stop advertising this node against the service encoded in the input service_id string.

start_discovering(const char* service_id)

Start discovering and maintaining search tables for the service encoded in the input service_id string.

stop_discovering(const char* service_id)

Stop discovering and maintenance of search tables for the service encoded in the input service_id string.

AdvertisementList lookup(const char* service_id)

Lookup and return advertisements for peers supporting the service encoded in the input service_id string, using the underlying discovery protocol.

It is RECOMMENDED to use start_discovering in advance of any lookup for each service_id as a way to speed up search.

AdvertisementList lookup_random()

Unused, reserved for future use.

Copyright

Copyright and related rights waived via CC0.

References

• logos service discovery