| /* |
| * |
| * Copyright 2015, Google Inc. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| */ |
| |
| #ifndef GRPC_CORE_EXT_CLIENT_CHANNEL_LB_POLICY_H |
| #define GRPC_CORE_EXT_CLIENT_CHANNEL_LB_POLICY_H |
| |
| #include "src/core/ext/client_channel/subchannel.h" |
| #include "src/core/lib/iomgr/polling_entity.h" |
| #include "src/core/lib/transport/connectivity_state.h" |
| |
| /** A load balancing policy: specified by a vtable and a struct (which |
| is expected to be extended to contain some parameters) */ |
| typedef struct grpc_lb_policy grpc_lb_policy; |
| typedef struct grpc_lb_policy_vtable grpc_lb_policy_vtable; |
| |
| typedef void (*grpc_lb_completion)(void *cb_arg, grpc_subchannel *subchannel, |
| grpc_status_code status, const char *errmsg); |
| |
| struct grpc_lb_policy { |
| const grpc_lb_policy_vtable *vtable; |
| gpr_atm ref_pair; |
| /* owned pointer to interested parties in load balancing decisions */ |
| grpc_pollset_set *interested_parties; |
| }; |
| |
| /** Extra arguments for an LB pick */ |
| typedef struct grpc_lb_policy_pick_args { |
| /** Initial metadata associated with the picking call. */ |
| grpc_metadata_batch *initial_metadata; |
| /** Bitmask used for selective cancelling. See \a |
| * grpc_lb_policy_cancel_picks() and \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; |
| /** Deadline for the call to the LB server */ |
| gpr_timespec deadline; |
| } 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); |
| |
| /** \see grpc_lb_policy_pick */ |
| int (*pick)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, |
| 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, grpc_error *error); |
| |
| /** \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, grpc_error *error); |
| |
| /** \see grpc_lb_policy_ping_one */ |
| void (*ping_one)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, |
| grpc_closure *closure); |
| |
| /** Try to enter a READY connectivity state */ |
| void (*exit_idle)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy); |
| |
| /** check the current connectivity of the lb_policy */ |
| grpc_connectivity_state (*check_connectivity)( |
| grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, |
| grpc_error **connectivity_error); |
| |
| /** 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. */ |
| void (*notify_on_state_change)(grpc_exec_ctx *exec_ctx, |
| grpc_lb_policy *policy, |
| grpc_connectivity_state *state, |
| grpc_closure *closure); |
| }; |
| |
| /*#define GRPC_LB_POLICY_REFCOUNT_DEBUG*/ |
| #ifdef GRPC_LB_POLICY_REFCOUNT_DEBUG |
| #define GRPC_LB_POLICY_REF(p, r) \ |
| grpc_lb_policy_ref((p), __FILE__, __LINE__, (r)) |
| #define GRPC_LB_POLICY_UNREF(exec_ctx, p, r) \ |
| grpc_lb_policy_unref((exec_ctx), (p), __FILE__, __LINE__, (r)) |
| #define GRPC_LB_POLICY_WEAK_REF(p, r) \ |
| grpc_lb_policy_weak_ref((p), __FILE__, __LINE__, (r)) |
| #define GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, p, r) \ |
| grpc_lb_policy_weak_unref((exec_ctx), (p), __FILE__, __LINE__, (r)) |
| void grpc_lb_policy_ref(grpc_lb_policy *policy, const char *file, int line, |
| const char *reason); |
| void grpc_lb_policy_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, |
| const char *file, int line, const char *reason); |
| void grpc_lb_policy_weak_ref(grpc_lb_policy *policy, const char *file, int line, |
| const char *reason); |
| void grpc_lb_policy_weak_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, |
| const char *file, int line, const char *reason); |
| #else |
| #define GRPC_LB_POLICY_REF(p, r) grpc_lb_policy_ref((p)) |
| #define GRPC_LB_POLICY_UNREF(cl, p, r) grpc_lb_policy_unref((cl), (p)) |
| #define GRPC_LB_POLICY_WEAK_REF(p, r) grpc_lb_policy_weak_ref((p)) |
| #define GRPC_LB_POLICY_WEAK_UNREF(cl, p, r) grpc_lb_policy_weak_unref((cl), (p)) |
| void grpc_lb_policy_ref(grpc_lb_policy *policy); |
| void grpc_lb_policy_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy); |
| void grpc_lb_policy_weak_ref(grpc_lb_policy *policy); |
| void grpc_lb_policy_weak_unref(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy); |
| #endif |
| |
| /** called by concrete implementations to initialize the base struct */ |
| void grpc_lb_policy_init(grpc_lb_policy *policy, |
| const grpc_lb_policy_vtable *vtable); |
| |
| /** Finds an appropriate subchannel for a call, based on \a pick_args. |
| |
| \a target will be set to the selected subchannel, or NULL on failure. |
| Upon success, \a user_data will be set to whatever opaque information |
| may need to be propagated from the LB policy, or NULL if not needed. |
| |
| If the pick succeeds and a result is known immediately, a non-zero |
| value will be returned. Otherwise, \a on_complete will be invoked |
| once the pick is complete with its error argument set to indicate |
| success or failure. |
| |
| Any IO should be done under the \a interested_parties \a grpc_pollset_set |
| in the \a grpc_lb_policy struct. */ |
| int grpc_lb_policy_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, |
| 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, |
| grpc_error *error); |
| |
| /** 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, |
| uint32_t initial_metadata_flags_eq, |
| grpc_error *error); |
| |
| /** Try to enter a READY connectivity state */ |
| void grpc_lb_policy_exit_idle(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy); |
| |
| /* Call notify when the connectivity state of a channel changes from \a *state. |
| * Updates \a *state with the new state of the policy */ |
| void grpc_lb_policy_notify_on_state_change(grpc_exec_ctx *exec_ctx, |
| grpc_lb_policy *policy, |
| grpc_connectivity_state *state, |
| grpc_closure *closure); |
| |
| grpc_connectivity_state grpc_lb_policy_check_connectivity( |
| grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy, |
| grpc_error **connectivity_error); |
| |
| #endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_LB_POLICY_H */ |