Documentation
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Overview ¶
Package a2a is Harbor's southbound A2A integration with the tool catalog (Phase 29). It implements `tools.ToolProvider` by composing the wire `distributed.RemoteTransport` (`internal/distributed/drivers/a2a`) with the catalog's standard `RunWithPolicyHooked` shell.
Discovery model. The Provider is parameterised by a single peer's base URL plus a wire `distributed.RemoteTransport` instance. At `Connect`, the Provider issues a `GetExtendedAgentCard` against the peer; `Discover` materialises each `AgentSkill` from the card into a `tools.ToolDescriptor` with `Transport: TransportA2A` and an Invoke closure that translates the catalog-edge JSON-RawMessage into an A2A `Message` with a `TextPart`, dispatches via the transport, and returns the resulting `a2a.Task` as the `ToolResult.Value`.
One Provider per peer. Operators wanting to register N peers instantiate N Providers; the catalog presents the union as one set of `Tool`s. The `SourceID` is derived from the peer URL so observability + audit can attribute each tool to its origin.
Reliability shell (D-024). Every Invoke routes through `tools.RunWithPolicyHooked` so timeout / retry / validation happen once, in the same place, regardless of transport. The wire driver does NOT add its own shell.
Concurrent reuse (D-025). Provider is constructed once with an immutable peer URL + transport reference; Connect / Discover / Close take an internal Mutex so concurrent calls are serialised; Invoke is stateless on the Provider and dispatches through the shared transport.
Index ¶
Constants ¶
const DriverName = "a2a"
DriverName documents the conceptual driver identifier. The tools subsystem has no driver-factory registry (catalogs are constructed in code), so this constant is for documentation + audit logging.
Variables ¶
var ( // ErrNotConnected — Discover or invocation called before Connect. ErrNotConnected = errors.New("tools/a2a: provider not connected") // ErrAgentSkillEmpty — discovered card declared zero skills. ErrAgentSkillEmpty = errors.New("tools/a2a: AgentCard declares no skills") )
Sentinels.
Functions ¶
This section is empty.
Types ¶
type Option ¶
type Option func(*config)
Option configures a Provider at construction.
func WithDescriptorOptions ¶
func WithDescriptorOptions(opts ...tools.DescriptorOption) Option
WithDescriptorOptions injects per-skill descriptor options applied to every materialised Tool. Use this to override the policy shell (e.g. tighter timeouts for chatty peers) or to add audit tags.
func WithToolNamePrefix ¶
WithToolNamePrefix prepends prefix + "." to every materialised tool's Name. The default is the peer URL's host (so two peers can expose a skill named "echo" without colliding).
type Provider ¶
type Provider struct {
// contains filtered or unexported fields
}
Provider implements `tools.ToolProvider` for a single A2A peer.
func New ¶
func New(peerURL string, transport distributed.RemoteTransport, opts ...Option) (*Provider, error)
New constructs a Provider. `peerURL` is the peer's canonical base URL (matches a registered peer on the wire transport's Registry); `transport` is the wire `distributed.RemoteTransport`.
Returns an error when peerURL is empty or transport is nil — the Provider is unusable in either case.
func (*Provider) Close ¶
Close is a no-op: the Provider does not own the transport (the caller does). Multiple Closes are safe.
func (*Provider) Connect ¶
Connect fetches the AgentCard via the wire transport's `GetExtendedAgentCard`. Identity is read from ctx and propagated through the wire driver.
Connect is idempotent: a second call refreshes the cached card so callers can use Connect as a "manual cache invalidation" hook.
func (*Provider) Discover ¶
Discover returns one ToolDescriptor per `AgentSkill` on the cached AgentCard. Returns ErrNotConnected when Connect has not run; ErrAgentSkillEmpty when the card lists no skills.
func (*Provider) SourceID ¶
func (p *Provider) SourceID() tools.ToolSourceID
SourceID returns the stable per-peer identifier surfaced on every materialised Tool.Source.
Source Files