Merge pull request #5691 from ctiller/idempotent

Idempotent request support for core

2 files changed, 40 insertions, 5 deletions

diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index 0219d7e6d0..77ad410b50 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -912,7 +912,7 @@ static void set_cancelled_value(grpc_status_code status, void *dest) {
   *(int *)dest = (status != GRPC_STATUS_OK);
 }
 
-static int are_write_flags_valid(uint32_t flags) {
+static bool are_write_flags_valid(uint32_t flags) {
   /* check that only bits in GRPC_WRITE_(INTERNAL?)_USED_MASK are set */
   const uint32_t allowed_write_positions =
       (GRPC_WRITE_USED_MASK | GRPC_WRITE_INTERNAL_USED_MASK);
@@ -920,6 +920,15 @@ static int are_write_flags_valid(uint32_t flags) {
   return !(flags & invalid_positions);
 }
 
+static bool are_initial_metadata_flags_valid(uint32_t flags, bool is_client) {
+  /* check that only bits in GRPC_WRITE_(INTERNAL?)_USED_MASK are set */
+  uint32_t invalid_positions = ~GRPC_INITIAL_METADATA_USED_MASK;
+  if (!is_client) {
+    invalid_positions |= GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST;
+  }
+  return !(flags & invalid_positions);
+}
+
 static batch_control *allocate_batch_control(grpc_call *call) {
   size_t i;
   for (i = 0; i < MAX_CONCURRENT_BATCHES; i++) {
@@ -1199,7 +1208,7 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
     switch (op->op) {
       case GRPC_OP_SEND_INITIAL_METADATA:
         /* Flag validation: currently allow no flags */
-        if (op->flags != 0) {
+        if (!are_initial_metadata_flags_valid(op->flags, call->is_client)) {
           error = GRPC_CALL_ERROR_INVALID_FLAGS;
           goto done_with_error;
         }
@@ -1223,6 +1232,8 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         call->metadata_batch[0][0].deadline = call->send_deadline;
         stream_op.send_initial_metadata =
             &call->metadata_batch[0 /* is_receiving */][0 /* is_trailing */];
+        stream_op.send_idempotent_request =
+            (op->flags & GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST) != 0;
         break;
       case GRPC_OP_SEND_MESSAGE:
         if (!are_write_flags_valid(op->flags)) {
diff --git a/src/core/lib/surface/server.c b/src/core/lib/surface/server.c
index 080734e9d5..55e5e49e11 100644
--- a/src/core/lib/surface/server.c
+++ b/src/core/lib/surface/server.c
@@ -100,6 +100,7 @@ typedef struct requested_call {
 
 typedef struct channel_registered_method {
   registered_method *server_registered_method;
+  uint32_t flags;
   grpc_mdstr *method;
   grpc_mdstr *host;
 } channel_registered_method;
@@ -152,6 +153,7 @@ struct call_data {
   grpc_completion_queue *cq_new;
 
   grpc_metadata_batch *recv_initial_metadata;
+  bool recv_idempotent_request;
   grpc_metadata_array initial_metadata;
 
   grpc_closure got_initial_metadata;
@@ -171,6 +173,7 @@ struct request_matcher {
 struct registered_method {
   char *method;
   char *host;
+  uint32_t flags;
   request_matcher request_matcher;
   registered_method *next;
 };
@@ -468,6 +471,9 @@ static void start_new_rpc(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
       if (!rm) break;
       if (rm->host != calld->host) continue;
       if (rm->method != calld->path) continue;
+      if ((rm->flags & GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST) &&
+          !calld->recv_idempotent_request)
+        continue;
       finish_start_new_rpc(exec_ctx, server, elem,
                            &rm->server_registered_method->request_matcher);
       return;
@@ -480,6 +486,9 @@ static void start_new_rpc(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
       if (!rm) break;
       if (rm->host != NULL) continue;
       if (rm->method != calld->path) continue;
+      if ((rm->flags & GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST) &&
+          !calld->recv_idempotent_request)
+        continue;
       finish_start_new_rpc(exec_ctx, server, elem,
                            &rm->server_registered_method->request_matcher);
       return;
@@ -598,9 +607,11 @@ static void server_mutate_op(grpc_call_element *elem,
   call_data *calld = elem->call_data;
 
   if (op->recv_initial_metadata != NULL) {
+    GPR_ASSERT(op->recv_idempotent_request == NULL);
     calld->recv_initial_metadata = op->recv_initial_metadata;
     calld->on_done_recv_initial_metadata = op->recv_initial_metadata_ready;
     op->recv_initial_metadata_ready = &calld->server_on_recv_initial_metadata;
+    op->recv_idempotent_request = &calld->recv_idempotent_request;
   }
 }
 
@@ -830,10 +841,12 @@ static int streq(const char *a, const char *b) {
 }
 
 void *grpc_server_register_method(grpc_server *server, const char *method,
-                                  const char *host) {
+                                  const char *host, uint32_t flags) {
   registered_method *m;
-  GRPC_API_TRACE("grpc_server_register_method(server=%p, method=%s, host=%s)",
-                 3, (server, method, host));
+  GRPC_API_TRACE(
+      "grpc_server_register_method(server=%p, method=%s, host=%s, "
+      "flags=0x%08x)",
+      4, (server, method, host, flags));
   if (!method) {
     gpr_log(GPR_ERROR,
             "grpc_server_register_method method string cannot be NULL");
@@ -846,12 +859,18 @@ void *grpc_server_register_method(grpc_server *server, const char *method,
       return NULL;
     }
   }
+  if ((flags & ~GRPC_INITIAL_METADATA_USED_MASK) != 0) {
+    gpr_log(GPR_ERROR, "grpc_server_register_method invalid flags 0x%08x",
+            flags);
+    return NULL;
+  }
   m = gpr_malloc(sizeof(registered_method));
   memset(m, 0, sizeof(*m));
   request_matcher_init(&m->request_matcher, server->max_requested_calls);
   m->method = gpr_strdup(method);
   m->host = gpr_strdup(host);
   m->next = server->registered_methods;
+  m->flags = flags;
   server->registered_methods = m;
   return m;
 }
@@ -930,6 +949,7 @@ void grpc_server_setup_transport(grpc_exec_ctx *exec_ctx, grpc_server *s,
       if (probes > max_probes) max_probes = probes;
       crm = &chand->registered_methods[(hash + probes) % slots];
       crm->server_registered_method = rm;
+      crm->flags = rm->flags;
       crm->host = host;
       crm->method = method;
     }
@@ -1247,6 +1267,10 @@ static void begin_call(grpc_exec_ctx *exec_ctx, grpc_server *server,
       cpstr(&rc->data.batch.details->method,
             &rc->data.batch.details->method_capacity, calld->path);
       rc->data.batch.details->deadline = calld->deadline;
+      rc->data.batch.details->flags =
+          0 | (calld->recv_idempotent_request
+                   ? GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST
+                   : 0);
       break;
     case REGISTERED_CALL:
       *rc->data.registered.deadline = calld->deadline;