src/core/census/grpc_filter.c

/*
 *
 * 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.
 *
 */

#include "src/core/census/grpc_filter.h"

#include <stdio.h>
#include <string.h>

#include "src/core/channel/channel_stack.h"
#include "src/core/channel/noop_filter.h"
#include "src/core/statistics/census_interface.h"
#include "src/core/statistics/census_rpc_stats.h"
#include <grpc/census.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/slice.h>
#include <grpc/support/time.h>

typedef struct call_data
{
  census_op_id op_id;
  census_context *ctxt;
  gpr_timespec start_ts;
  int error;

  /* recv callback */
  grpc_stream_op_buffer *recv_ops;
  grpc_closure *on_done_recv;
} call_data;

typedef struct channel_data
{
  grpc_mdstr *path_str;		/* pointer to meta data str with key == ":path" */
} channel_data;

static void
extract_and_annotate_method_tag (grpc_stream_op_buffer * sopb, call_data * calld, channel_data * chand)
{
  grpc_linked_mdelem *m;
  size_t i;
  for (i = 0; i < sopb->nops; i++)
    {
      grpc_stream_op *op = &sopb->ops[i];
      if (op->type != GRPC_OP_METADATA)
	continue;
      for (m = op->data.metadata.list.head; m != NULL; m = m->next)
	{
	  if (m->md->key == chand->path_str)
	    {
	      gpr_log (GPR_DEBUG, "%s", (const char *) GPR_SLICE_START_PTR (m->md->value->slice));
	      /* Add method tag here */
	    }
	}
    }
}

static void
client_mutate_op (grpc_call_element * elem, grpc_transport_stream_op * op)
{
  call_data *calld = elem->call_data;
  channel_data *chand = elem->channel_data;
  if (op->send_ops)
    {
      extract_and_annotate_method_tag (op->send_ops, calld, chand);
    }
}

static void
client_start_transport_op (grpc_exec_ctx * exec_ctx, grpc_call_element * elem, grpc_transport_stream_op * op)
{
  client_mutate_op (elem, op);
  grpc_call_next_op (exec_ctx, elem, op);
}

static void
server_on_done_recv (grpc_exec_ctx * exec_ctx, void *ptr, int success)
{
  grpc_call_element *elem = ptr;
  call_data *calld = elem->call_data;
  channel_data *chand = elem->channel_data;
  if (success)
    {
      extract_and_annotate_method_tag (calld->recv_ops, calld, chand);
    }
  calld->on_done_recv->cb (exec_ctx, calld->on_done_recv->cb_arg, success);
}

static void
server_mutate_op (grpc_call_element * elem, grpc_transport_stream_op * op)
{
  call_data *calld = elem->call_data;
  if (op->recv_ops)
    {
      /* substitute our callback for the op callback */
      calld->recv_ops = op->recv_ops;
      calld->on_done_recv = op->on_done_recv;
      op->on_done_recv = calld->on_done_recv;
    }
}

static void
server_start_transport_op (grpc_exec_ctx * exec_ctx, grpc_call_element * elem, grpc_transport_stream_op * op)
{
  call_data *calld = elem->call_data;
  GPR_ASSERT ((calld->op_id.upper != 0) || (calld->op_id.lower != 0));
  server_mutate_op (elem, op);
  grpc_call_next_op (exec_ctx, elem, op);
}

static void
client_init_call_elem (grpc_exec_ctx * exec_ctx, grpc_call_element * elem, const void *server_transport_data, grpc_transport_stream_op * initial_op)
{
  call_data *d = elem->call_data;
  GPR_ASSERT (d != NULL);
  d->start_ts = gpr_now (GPR_CLOCK_REALTIME);
  if (initial_op)
    client_mutate_op (elem, initial_op);
}

static void
client_destroy_call_elem (grpc_exec_ctx * exec_ctx, grpc_call_element * elem)
{
  call_data *d = elem->call_data;
  GPR_ASSERT (d != NULL);
  /* TODO(hongyu): record rpc client stats and census_rpc_end_op here */
}

static void
server_init_call_elem (grpc_exec_ctx * exec_ctx, grpc_call_element * elem, const void *server_transport_data, grpc_transport_stream_op * initial_op)
{
  call_data *d = elem->call_data;
  GPR_ASSERT (d != NULL);
  d->start_ts = gpr_now (GPR_CLOCK_REALTIME);
  /* TODO(hongyu): call census_tracing_start_op here. */
  grpc_closure_init (d->on_done_recv, server_on_done_recv, elem);
  if (initial_op)
    server_mutate_op (elem, initial_op);
}

static void
server_destroy_call_elem (grpc_exec_ctx * exec_ctx, grpc_call_element * elem)
{
  call_data *d = elem->call_data;
  GPR_ASSERT (d != NULL);
  /* TODO(hongyu): record rpc server stats and census_tracing_end_op here */
}

static void
init_channel_elem (grpc_exec_ctx * exec_ctx, grpc_channel_element * elem, grpc_channel * master, const grpc_channel_args * args, grpc_mdctx * mdctx, int is_first, int is_last)
{
  channel_data *chand = elem->channel_data;
  GPR_ASSERT (chand != NULL);
  chand->path_str = grpc_mdstr_from_string (mdctx, ":path", 0);
}

static void
destroy_channel_elem (grpc_exec_ctx * exec_ctx, grpc_channel_element * elem)
{
  channel_data *chand = elem->channel_data;
  GPR_ASSERT (chand != NULL);
  if (chand->path_str != NULL)
    {
      GRPC_MDSTR_UNREF (chand->path_str);
    }
}

const grpc_channel_filter grpc_client_census_filter = {
  client_start_transport_op, grpc_channel_next_op,
  sizeof (call_data), client_init_call_elem,
  client_destroy_call_elem, sizeof (channel_data),
  init_channel_elem, destroy_channel_elem,
  grpc_call_next_get_peer, "census-client"
};

const grpc_channel_filter grpc_server_census_filter = {
  server_start_transport_op, grpc_channel_next_op,
  sizeof (call_data), server_init_call_elem,
  server_destroy_call_elem, sizeof (channel_data),
  init_channel_elem, destroy_channel_elem,
  grpc_call_next_get_peer, "census-server"
};