Client configuration libary - headers & docs
Initial sketch of a client configuration library. It's expected this
will subsume the client_setup functionality that we currently have, and
begin providing customizable load balancing support.
Releasing the headers now (no implementation work has been done) so that
we can bat around thoughts on this and make sure all the use cases are
implementable, and our primary use cases are easily so.
diff --git a/src/core/client_config/lb_policy.h b/src/core/client_config/lb_policy.h
new file mode 100644
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+++ b/src/core/client_config/lb_policy.h
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+/*
+ *
+ * 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_INTERNAL_CORE_CLIENT_CONFIG_LB_POLICY_H
+#define GRPC_INTERNAL_CORE_CLIENT_CONFIG_LB_POLICY_H
+
+#include "src/core/client_config/configured_channel.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_configured_channel *configured_channel,
+ grpc_status_code status, const char *errmsg);
+
+struct grpc_lb_policy_vtable {
+ void (*ref)(grpc_lb_policy *policy);
+ void (*unref)(grpc_lb_policy *policy);
+
+ void (*shutdown)(grpc_lb_policy *policy);
+
+ /** implement grpc_lb_policy_pick */
+ void (*pick)(grpc_lb_policy *policy, grpc_pollset *pollset,
+ grpc_metadata_batch *initial_metadata,
+ grpc_configured_channel **target,
+ grpc_iomgr_closure *on_complete);
+};
+
+/** Start shutting down (fail any pending picks) */
+void grpc_lb_policy_shutdown(grpc_lb_policy *policy);
+
+/** 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 pollset. */
+void grpc_lb_policy_pick(grpc_lb_policy *policy, grpc_pollset *pollset,
+ grpc_metadata_batch *initial_metadata,
+ grpc_configured_channel **target,
+ grpc_iomgr_closure *on_complete);
+
+#endif /* GRPC_INTERNAL_CORE_CONFIG_LB_POLICY_H */