diff options
Diffstat (limited to 'src/core/ext/client_config/lb_policy.h')
-rw-r--r-- | src/core/ext/client_config/lb_policy.h | 60 |
1 files changed, 41 insertions, 19 deletions
diff --git a/src/core/ext/client_config/lb_policy.h b/src/core/ext/client_config/lb_policy.h index a2f5446fc6..37c93d707c 100644 --- a/src/core/ext/client_config/lb_policy.h +++ b/src/core/ext/client_config/lb_policy.h @@ -53,23 +53,38 @@ struct grpc_lb_policy { grpc_pollset_set *interested_parties; }; +/** Extra arguments for an LB pick */ +typedef struct grpc_lb_policy_pick_args { + /** Parties interested in the pick's progress */ + grpc_polling_entity *pollent; + /** Initial metadata associated with the picking call. */ + grpc_metadata_batch *initial_metadata; + /** See \a GRPC_INITIAL_METADATA_* in grpc_types.h */ + uint32_t initial_metadata_flags; + /** Storage for LB token in \a initial_metadata, or NULL if not used */ + grpc_linked_mdelem *lb_token_mdelem_storage; +} grpc_lb_policy_pick_args; + struct grpc_lb_policy_vtable { void (*destroy)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy); - void (*shutdown)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy); - /** implement grpc_lb_policy_pick */ + /** \see grpc_lb_policy_pick */ int (*pick)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, - grpc_polling_entity *pollent, - grpc_metadata_batch *initial_metadata, - uint32_t initial_metadata_flags, - grpc_connected_subchannel **target, grpc_closure *on_complete); + const grpc_lb_policy_pick_args *pick_args, + grpc_connected_subchannel **target, void **user_data, + grpc_closure *on_complete); + + /** \see grpc_lb_policy_cancel_pick */ void (*cancel_pick)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, grpc_connected_subchannel **target); + + /** \see grpc_lb_policy_cancel_picks */ void (*cancel_picks)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, uint32_t initial_metadata_flags_mask, uint32_t initial_metadata_flags_eq); + /** \see grpc_lb_policy_ping_one */ void (*ping_one)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, grpc_closure *closure); @@ -83,8 +98,7 @@ struct grpc_lb_policy_vtable { /** call notify when the connectivity state of a channel changes from *state. Updates *state with the new state of the policy. Calling with a NULL \a - state cancels the subscription. - */ + state cancels the subscription. */ void (*notify_on_state_change)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, grpc_connectivity_state *state, @@ -124,26 +138,34 @@ void grpc_lb_policy_weak_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy); void grpc_lb_policy_init(grpc_lb_policy *policy, const grpc_lb_policy_vtable *vtable); -/** Given initial metadata in \a initial_metadata, find an appropriate - target for this rpc, and 'return' it by calling \a on_complete after setting - \a target. - Picking can be asynchronous. Any IO should be done under \a pollent. */ +/** Find an appropriate target for this call, based on \a pick_args. + Picking can be synchronous or asynchronous. In the synchronous case, when a + pick is readily available, it'll be returned in \a target and a non-zero + value will be returned. + In the asynchronous case, zero is returned and \a on_complete will be called + once \a target and \a user_data have been set. Any IO should be done under + \a pick_args->pollent. The opaque \a user_data output argument corresponds + to information that may need be propagated from the LB policy. It may be + NULL. Errors are signaled by receiving a NULL \a *target. */ int grpc_lb_policy_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, - grpc_polling_entity *pollent, - grpc_metadata_batch *initial_metadata, - uint32_t initial_metadata_flags, - grpc_connected_subchannel **target, + const grpc_lb_policy_pick_args *pick_args, + grpc_connected_subchannel **target, void **user_data, grpc_closure *on_complete); +/** Perform a connected subchannel ping (see \a grpc_connected_subchannel_ping) + against one of the connected subchannels managed by \a policy. */ void grpc_lb_policy_ping_one(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, grpc_closure *closure); +/** Cancel picks for \a target. + The \a on_complete callback of the pending picks will be invoked with \a + *target set to NULL. */ void grpc_lb_policy_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, grpc_connected_subchannel **target); -/** Cancel all pending picks which have: - (initial_metadata_flags & initial_metadata_flags_mask) == - initial_metadata_flags_eq */ +/** Cancel all pending picks for which their \a initial_metadata_flags (as given + in the call to \a grpc_lb_policy_pick) matches \a initial_metadata_flags_eq + when AND'd with \a initial_metadata_flags_mask */ void grpc_lb_policy_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, uint32_t initial_metadata_flags_mask, |