Allow servers to select compression level via initial MD.

Setting the newly added compression_level field of
grpc_op::send_initial_metadata by a server now has the effect of
applying that compression level for the subsequent call messages leaving
the server. The ultimate meaning of the level depends on the client's
supported compression algorithms.

9 files changed, 146 insertions, 92 deletions

diff --git a/src/core/lib/compression/compression_algorithm.c b/src/core/lib/compression/compression_algorithm.c
index 7039364b7b..142f3fffa5 100644
--- a/src/core/lib/compression/compression_algorithm.c
+++ b/src/core/lib/compression/compression_algorithm.c
@@ -125,62 +125,6 @@ grpc_mdelem *grpc_compression_encoding_mdelem(
   return NULL;
 }
 
-/* TODO(dgq): Add the ability to specify parameters to the individual
- * compression algorithms */
-grpc_compression_algorithm grpc_compression_algorithm_for_level(
-    grpc_compression_level level, uint32_t accepted_encodings) {
-  GRPC_API_TRACE("grpc_compression_algorithm_for_level(level=%d)", 1,
-                 ((int)level));
-  if (level > GRPC_COMPRESS_LEVEL_HIGH) {
-    gpr_log(GPR_ERROR, "Unknown compression level %d.", (int)level);
-    abort();
-  }
-
-  const size_t num_supported =
-      GPR_BITCOUNT(accepted_encodings) - 1; /* discard NONE */
-  if (level == GRPC_COMPRESS_LEVEL_NONE || num_supported == 0) {
-    return GRPC_COMPRESS_NONE;
-  }
-
-  GPR_ASSERT(level > 0);
-
-  /* Establish a "ranking" or compression algorithms in increasing order of
-   * compression.
-   * This is simplistic and we will probably want to introduce other dimensions
-   * in the future (cpu/memory cost, etc). */
-  const grpc_compression_algorithm algos_ranking[] = {GRPC_COMPRESS_GZIP,
-                                                      GRPC_COMPRESS_DEFLATE};
-
-  /* intersect algos_ranking with the supported ones keeping the ranked order */
-  grpc_compression_algorithm
-      sorted_supported_algos[GRPC_COMPRESS_ALGORITHMS_COUNT];
-  size_t algos_supported_idx = 0;
-  for (size_t i = 0; i < GPR_ARRAY_SIZE(algos_ranking); i++) {
-    const grpc_compression_algorithm alg = algos_ranking[i];
-    for (size_t j = 0; j < num_supported; j++) {
-      if (GPR_BITGET(accepted_encodings, alg) == 1) {
-        /* if \a alg in supported */
-        sorted_supported_algos[algos_supported_idx++] = alg;
-        break;
-      }
-    }
-    if (algos_supported_idx == num_supported) break;
-  }
-
-  switch (level) {
-    case GRPC_COMPRESS_LEVEL_NONE:
-      abort(); /* should have been handled already */
-    case GRPC_COMPRESS_LEVEL_LOW:
-      return sorted_supported_algos[0];
-    case GRPC_COMPRESS_LEVEL_MED:
-      return sorted_supported_algos[num_supported / 2];
-    case GRPC_COMPRESS_LEVEL_HIGH:
-      return sorted_supported_algos[num_supported - 1];
-    default:
-      abort();
-  };
-}
-
 void grpc_compression_options_init(grpc_compression_options *opts) {
   opts->enabled_algorithms_bitset = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
   opts->default_compression_algorithm = GRPC_COMPRESS_NONE;
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index 9b2b94eedf..911b5b80bb 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -420,6 +420,65 @@ grpc_compression_algorithm grpc_call_test_only_get_compression_algorithm(
   return algorithm;
 }
 
+static grpc_compression_algorithm compression_algorithm_for_level_locked(
+    grpc_call *call, grpc_compression_level level) {
+  /* Establish a "ranking" or compression algorithms in increasing order of
+   * compression.
+   * This is simplistic and we will probably want to introduce other
+   * dimensions
+   * in the future (cpu/memory cost, etc). */
+  const grpc_compression_algorithm algos_ranking[] = {GRPC_COMPRESS_GZIP,
+                                                      GRPC_COMPRESS_DEFLATE};
+  const uint32_t accepted_encodings = call->encodings_accepted_by_peer;
+  if (level > GRPC_COMPRESS_LEVEL_HIGH) {
+    extern int grpc_compress_filter_trace;
+    if (grpc_compress_filter_trace) {
+      gpr_log(GPR_ERROR,
+              "Unknown compression level %d. Compression will be disabled.",
+              (int)level);
+    }
+    return GRPC_COMPRESS_NONE;
+  }
+
+  const size_t num_supported =
+      GPR_BITCOUNT(accepted_encodings) - 1; /* discard NONE */
+  if (level == GRPC_COMPRESS_LEVEL_NONE || num_supported == 0) {
+    return GRPC_COMPRESS_NONE;
+  }
+
+  GPR_ASSERT(level > 0);
+
+  /* intersect algos_ranking with the supported ones keeping the ranked order
+   */
+  grpc_compression_algorithm
+      sorted_supported_algos[GRPC_COMPRESS_ALGORITHMS_COUNT];
+  size_t algos_supported_idx = 0;
+  for (size_t i = 0; i < GPR_ARRAY_SIZE(algos_ranking); i++) {
+    const grpc_compression_algorithm alg = algos_ranking[i];
+    for (size_t j = 0; j < num_supported; j++) {
+      if (GPR_BITGET(accepted_encodings, alg) == 1) {
+        /* if \a alg in supported */
+        sorted_supported_algos[algos_supported_idx++] = alg;
+        break;
+      }
+    }
+    if (algos_supported_idx == num_supported) break;
+  }
+
+  switch (level) {
+    case GRPC_COMPRESS_LEVEL_NONE:
+      abort(); /* should have been handled already */
+    case GRPC_COMPRESS_LEVEL_LOW:
+      return sorted_supported_algos[0];
+    case GRPC_COMPRESS_LEVEL_MED:
+      return sorted_supported_algos[num_supported / 2];
+    case GRPC_COMPRESS_LEVEL_HIGH:
+      return sorted_supported_algos[num_supported - 1];
+    default:
+      abort();
+  };
+}
+
 uint32_t grpc_call_test_only_get_message_flags(grpc_call *call) {
   uint32_t flags;
   gpr_mu_lock(&call->mu);
@@ -545,15 +604,28 @@ static grpc_linked_mdelem *linked_from_md(grpc_metadata *md) {
   return (grpc_linked_mdelem *)&md->internal_data;
 }
 
+static grpc_metadata *get_md_elem(grpc_metadata *metadata,
+                                  grpc_metadata *additional_metadata, int i,
+                                  int count) {
+  grpc_metadata *res =
+      i < count ? &metadata[i] : &additional_metadata[i - count];
+  GPR_ASSERT(res);
+  return res;
+}
+
 static int prepare_application_metadata(grpc_call *call, int count,
                                         grpc_metadata *metadata,
                                         int is_trailing,
-                                        int prepend_extra_metadata) {
+                                        int prepend_extra_metadata,
+                                        grpc_metadata *additional_metadata,
+                                        int additional_metadata_count) {
+  int total_count = count + additional_metadata_count;
   int i;
   grpc_metadata_batch *batch =
       &call->metadata_batch[0 /* is_receiving */][is_trailing];
-  for (i = 0; i < count; i++) {
-    grpc_metadata *md = &metadata[i];
+  for (i = 0; i < total_count; i++) {
+    const grpc_metadata *md =
+        get_md_elem(metadata, additional_metadata, i, count);
     grpc_linked_mdelem *l = (grpc_linked_mdelem *)&md->internal_data;
     GPR_ASSERT(sizeof(grpc_linked_mdelem) == sizeof(md->internal_data));
     l->md = grpc_mdelem_from_string_and_buffer(
@@ -572,9 +644,10 @@ static int prepare_application_metadata(grpc_call *call, int count,
       break;
     }
   }
-  if (i != count) {
+  if (i != total_count) {
     for (int j = 0; j <= i; j++) {
-      grpc_metadata *md = &metadata[j];
+      const grpc_metadata *md =
+          get_md_elem(metadata, additional_metadata, j, count);
       grpc_linked_mdelem *l = (grpc_linked_mdelem *)&md->internal_data;
       GRPC_MDELEM_UNREF(l->md);
     }
@@ -595,24 +668,36 @@ static int prepare_application_metadata(grpc_call *call, int count,
       }
     }
   }
-  for (i = 1; i < count; i++) {
-    linked_from_md(&metadata[i])->prev = linked_from_md(&metadata[i - 1]);
+  for (i = 1; i < total_count; i++) {
+    grpc_metadata *md = get_md_elem(metadata, additional_metadata, i, count);
+    grpc_metadata *prev_md =
+        get_md_elem(metadata, additional_metadata, i - 1, count);
+    linked_from_md(md)->prev = linked_from_md(prev_md);
   }
-  for (i = 0; i < count - 1; i++) {
-    linked_from_md(&metadata[i])->next = linked_from_md(&metadata[i + 1]);
+  for (i = 0; i < total_count - 1; i++) {
+    grpc_metadata *md = get_md_elem(metadata, additional_metadata, i, count);
+    grpc_metadata *next_md =
+        get_md_elem(metadata, additional_metadata, i + 1, count);
+    linked_from_md(md)->next = linked_from_md(next_md);
   }
-  switch (prepend_extra_metadata * 2 + (count != 0)) {
+
+  switch (prepend_extra_metadata * 2 + (total_count != 0)) {
     case 0:
       /* no prepend, no metadata => nothing to do */
       batch->list.head = batch->list.tail = NULL;
       break;
-    case 1:
+    case 1: {
       /* metadata, but no prepend */
-      batch->list.head = linked_from_md(&metadata[0]);
-      batch->list.tail = linked_from_md(&metadata[count - 1]);
+      grpc_metadata *first_md =
+          get_md_elem(metadata, additional_metadata, 0, count);
+      grpc_metadata *last_md =
+          get_md_elem(metadata, additional_metadata, total_count - 1, count);
+      batch->list.head = linked_from_md(first_md);
+      batch->list.tail = linked_from_md(last_md);
       batch->list.head->prev = NULL;
       batch->list.tail->next = NULL;
       break;
+    }
     case 2:
       /* prepend, but no md */
       batch->list.head = &call->send_extra_metadata[0];
@@ -621,17 +706,22 @@ static int prepare_application_metadata(grpc_call *call, int count,
       batch->list.head->prev = NULL;
       batch->list.tail->next = NULL;
       break;
-    case 3:
+    case 3: {
       /* prepend AND md */
+      grpc_metadata *first_md =
+          get_md_elem(metadata, additional_metadata, 0, count);
+      grpc_metadata *last_md =
+          get_md_elem(metadata, additional_metadata, total_count - 1, count);
       batch->list.head = &call->send_extra_metadata[0];
       call->send_extra_metadata[call->send_extra_metadata_count - 1].next =
-          linked_from_md(&metadata[0]);
-      linked_from_md(&metadata[0])->prev =
+          linked_from_md(first_md);
+      linked_from_md(first_md)->prev =
           &call->send_extra_metadata[call->send_extra_metadata_count - 1];
-      batch->list.tail = linked_from_md(&metadata[count - 1]);
+      batch->list.tail = linked_from_md(last_md);
       batch->list.head->prev = NULL;
       batch->list.tail->next = NULL;
       break;
+    }
     default:
       GPR_UNREACHABLE_CODE(return 0);
   }
@@ -1229,7 +1319,29 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
           error = GRPC_CALL_ERROR_TOO_MANY_OPERATIONS;
           goto done_with_error;
         }
-        if (op->data.send_initial_metadata.count > INT_MAX) {
+        /* process compression level */
+        grpc_metadata compression_md;
+        memset(&compression_md, 0, sizeof(grpc_metadata));
+        size_t additional_metadata_count = 0;
+        if (op->data.send_initial_metadata.compression_level >
+            GRPC_COMPRESS_LEVEL_NONE) {
+          if (call->is_client) {
+            error = GRPC_CALL_ERROR_NOT_ON_CLIENT;
+            goto done_with_error;
+          }
+          const grpc_compression_algorithm calgo =
+              compression_algorithm_for_level_locked(
+                  call, op->data.send_initial_metadata.compression_level);
+          char *calgo_name;
+          grpc_compression_algorithm_name(calgo, &calgo_name);
+          compression_md.key = "grpc-internal-encoding-request";
+          compression_md.value = calgo_name;
+          compression_md.value_length = strlen(calgo_name);
+          additional_metadata_count++;
+        }
+
+        if (op->data.send_initial_metadata.count + additional_metadata_count >
+            INT_MAX) {
           error = GRPC_CALL_ERROR_INVALID_METADATA;
           goto done_with_error;
         }
@@ -1237,7 +1349,8 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         call->sent_initial_metadata = 1;
         if (!prepare_application_metadata(
                 call, (int)op->data.send_initial_metadata.count,
-                op->data.send_initial_metadata.metadata, 0, call->is_client)) {
+                op->data.send_initial_metadata.metadata, 0, call->is_client,
+                &compression_md, (int)additional_metadata_count)) {
           error = GRPC_CALL_ERROR_INVALID_METADATA;
           goto done_with_error;
         }
@@ -1325,7 +1438,8 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         if (!prepare_application_metadata(
                 call,
                 (int)op->data.send_status_from_server.trailing_metadata_count,
-                op->data.send_status_from_server.trailing_metadata, 1, 1)) {
+                op->data.send_status_from_server.trailing_metadata, 1, 1, NULL,
+                0)) {
           error = GRPC_CALL_ERROR_INVALID_METADATA;
           goto done_with_error;
         }
@@ -1513,9 +1627,10 @@ uint8_t grpc_call_is_client(grpc_call *call) { return call->is_client; }
 grpc_compression_algorithm grpc_call_compression_for_level(
     grpc_call *call, grpc_compression_level level) {
   gpr_mu_lock(&call->mu);
-  const uint32_t accepted_encodings = call->encodings_accepted_by_peer;
+  grpc_compression_algorithm algo =
+      compression_algorithm_for_level_locked(call, level);
   gpr_mu_unlock(&call->mu);
-  return grpc_compression_algorithm_for_level(level, accepted_encodings);
+  return algo;
 }
 
 const char *grpc_call_error_to_string(grpc_call_error error) {
diff --git a/src/csharp/ext/grpc_csharp_ext.c b/src/csharp/ext/grpc_csharp_ext.c
index 5b8ff9b819..49198cb708 100644
--- a/src/csharp/ext/grpc_csharp_ext.c
+++ b/src/csharp/ext/grpc_csharp_ext.c
@@ -503,6 +503,7 @@ grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
                            grpc_metadata_array *initial_metadata, uint32_t write_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[6];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -555,6 +556,7 @@ grpcsharp_call_start_client_streaming(grpc_call *call,
                                       grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[4];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -596,6 +598,7 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
     size_t send_buffer_len, grpc_metadata_array *initial_metadata, uint32_t write_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[4];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -638,6 +641,7 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
                                       grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[2];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -684,6 +688,7 @@ grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
                             int32_t send_empty_initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[2];
+  memset(ops, 0, sizeof(ops));
   size_t nops = send_empty_initial_metadata ? 2 : 1;
   ops[0].op = GRPC_OP_SEND_MESSAGE;
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
@@ -691,8 +696,6 @@ grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
   ops[0].flags = write_flags;
   ops[0].reserved = NULL;
   ops[1].op = GRPC_OP_SEND_INITIAL_METADATA;
-  ops[1].data.send_initial_metadata.count = 0;
-  ops[1].data.send_initial_metadata.metadata = NULL;
   ops[1].flags = 0;
   ops[1].reserved = NULL;
 
@@ -719,6 +722,7 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
     size_t optional_send_buffer_len, uint32_t write_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[3];
+  memset(ops, 0, sizeof(ops));
   size_t nops = 1;
   ops[0].op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   ops[0].data.send_status_from_server.status = status_code;
@@ -743,8 +747,6 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
   }
   if (send_empty_initial_metadata) {
     ops[nops].op = GRPC_OP_SEND_INITIAL_METADATA;
-    ops[nops].data.send_initial_metadata.count = 0;
-    ops[nops].data.send_initial_metadata.metadata = NULL;
     ops[nops].flags = 0;
     ops[nops].reserved = NULL;
     nops++;
@@ -784,6 +786,7 @@ grpcsharp_call_send_initial_metadata(grpc_call *call,
                                      grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[1];
+  memset(ops, 0, sizeof(ops));
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
diff --git a/src/objective-c/GRPCClient/private/GRPCWrappedCall.m b/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
index 16e5bff7ff..f72ec9068e 100644
--- a/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
+++ b/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
@@ -72,6 +72,7 @@
     _op.op = GRPC_OP_SEND_INITIAL_METADATA;
     _op.data.send_initial_metadata.count = metadata.count;
     _op.data.send_initial_metadata.metadata = metadata.grpc_metadataArray;
+    _op.data.send_initial_metadata.compression_level = 0;
     _handler = handler;
   }
   return self;
diff --git a/src/php/ext/grpc/call.c b/src/php/ext/grpc/call.c
index a0f3d160c6..227d61877b 100644
--- a/src/php/ext/grpc/call.c
+++ b/src/php/ext/grpc/call.c
@@ -291,6 +291,7 @@ PHP_METHOD(Call, startBatch) {
   grpc_metadata_array_init(&recv_trailing_metadata);
   MAKE_STD_ZVAL(result);
   object_init(result);
+  memset(ops, 0, sizeof(ops));
   /* "a" == 1 array */
   if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &array) ==
       FAILURE) {
diff --git a/src/python/grpcio/grpc/_cython/imports.generated.c b/src/python/grpcio/grpc/_cython/imports.generated.c
index 09551472b5..3daa6d6aff 100644
--- a/src/python/grpcio/grpc/_cython/imports.generated.c
+++ b/src/python/grpcio/grpc/_cython/imports.generated.c
@@ -72,7 +72,6 @@ census_view_get_data_type census_view_get_data_import;
 census_view_reset_type census_view_reset_import;
 grpc_compression_algorithm_parse_type grpc_compression_algorithm_parse_import;
 grpc_compression_algorithm_name_type grpc_compression_algorithm_name_import;
-grpc_compression_algorithm_for_level_type grpc_compression_algorithm_for_level_import;
 grpc_compression_options_init_type grpc_compression_options_init_import;
 grpc_compression_options_enable_algorithm_type grpc_compression_options_enable_algorithm_import;
 grpc_compression_options_disable_algorithm_type grpc_compression_options_disable_algorithm_import;
@@ -343,7 +342,6 @@ void pygrpc_load_imports(HMODULE library) {
   census_view_reset_import = (census_view_reset_type) GetProcAddress(library, "census_view_reset");
   grpc_compression_algorithm_parse_import = (grpc_compression_algorithm_parse_type) GetProcAddress(library, "grpc_compression_algorithm_parse");
   grpc_compression_algorithm_name_import = (grpc_compression_algorithm_name_type) GetProcAddress(library, "grpc_compression_algorithm_name");
-  grpc_compression_algorithm_for_level_import = (grpc_compression_algorithm_for_level_type) GetProcAddress(library, "grpc_compression_algorithm_for_level");
   grpc_compression_options_init_import = (grpc_compression_options_init_type) GetProcAddress(library, "grpc_compression_options_init");
   grpc_compression_options_enable_algorithm_import = (grpc_compression_options_enable_algorithm_type) GetProcAddress(library, "grpc_compression_options_enable_algorithm");
   grpc_compression_options_disable_algorithm_import = (grpc_compression_options_disable_algorithm_type) GetProcAddress(library, "grpc_compression_options_disable_algorithm");
diff --git a/src/python/grpcio/grpc/_cython/imports.generated.h b/src/python/grpcio/grpc/_cython/imports.generated.h
index 54c8aaad13..2a81352f0b 100644
--- a/src/python/grpcio/grpc/_cython/imports.generated.h
+++ b/src/python/grpcio/grpc/_cython/imports.generated.h
@@ -167,9 +167,6 @@ extern grpc_compression_algorithm_parse_type grpc_compression_algorithm_parse_im
 typedef int(*grpc_compression_algorithm_name_type)(grpc_compression_algorithm algorithm, char **name);
 extern grpc_compression_algorithm_name_type grpc_compression_algorithm_name_import;
 #define grpc_compression_algorithm_name grpc_compression_algorithm_name_import
-typedef grpc_compression_algorithm(*grpc_compression_algorithm_for_level_type)(grpc_compression_level level, uint32_t accepted_encodings);
-extern grpc_compression_algorithm_for_level_type grpc_compression_algorithm_for_level_import;
-#define grpc_compression_algorithm_for_level grpc_compression_algorithm_for_level_import
 typedef void(*grpc_compression_options_init_type)(grpc_compression_options *opts);
 extern grpc_compression_options_init_type grpc_compression_options_init_import;
 #define grpc_compression_options_init grpc_compression_options_init_import
diff --git a/src/ruby/ext/grpc/rb_grpc_imports.generated.c b/src/ruby/ext/grpc/rb_grpc_imports.generated.c
index cebbe8c40f..07d52d83da 100644
--- a/src/ruby/ext/grpc/rb_grpc_imports.generated.c
+++ b/src/ruby/ext/grpc/rb_grpc_imports.generated.c
@@ -72,7 +72,6 @@ census_view_get_data_type census_view_get_data_import;
 census_view_reset_type census_view_reset_import;
 grpc_compression_algorithm_parse_type grpc_compression_algorithm_parse_import;
 grpc_compression_algorithm_name_type grpc_compression_algorithm_name_import;
-grpc_compression_algorithm_for_level_type grpc_compression_algorithm_for_level_import;
 grpc_compression_options_init_type grpc_compression_options_init_import;
 grpc_compression_options_enable_algorithm_type grpc_compression_options_enable_algorithm_import;
 grpc_compression_options_disable_algorithm_type grpc_compression_options_disable_algorithm_import;
@@ -339,7 +338,6 @@ void grpc_rb_load_imports(HMODULE library) {
   census_view_reset_import = (census_view_reset_type) GetProcAddress(library, "census_view_reset");
   grpc_compression_algorithm_parse_import = (grpc_compression_algorithm_parse_type) GetProcAddress(library, "grpc_compression_algorithm_parse");
   grpc_compression_algorithm_name_import = (grpc_compression_algorithm_name_type) GetProcAddress(library, "grpc_compression_algorithm_name");
-  grpc_compression_algorithm_for_level_import = (grpc_compression_algorithm_for_level_type) GetProcAddress(library, "grpc_compression_algorithm_for_level");
   grpc_compression_options_init_import = (grpc_compression_options_init_type) GetProcAddress(library, "grpc_compression_options_init");
   grpc_compression_options_enable_algorithm_import = (grpc_compression_options_enable_algorithm_type) GetProcAddress(library, "grpc_compression_options_enable_algorithm");
   grpc_compression_options_disable_algorithm_import = (grpc_compression_options_disable_algorithm_type) GetProcAddress(library, "grpc_compression_options_disable_algorithm");
diff --git a/src/ruby/ext/grpc/rb_grpc_imports.generated.h b/src/ruby/ext/grpc/rb_grpc_imports.generated.h
index d7ea6c574c..6885e3926a 100644
--- a/src/ruby/ext/grpc/rb_grpc_imports.generated.h
+++ b/src/ruby/ext/grpc/rb_grpc_imports.generated.h
@@ -167,9 +167,6 @@ extern grpc_compression_algorithm_parse_type grpc_compression_algorithm_parse_im
 typedef int(*grpc_compression_algorithm_name_type)(grpc_compression_algorithm algorithm, char **name);
 extern grpc_compression_algorithm_name_type grpc_compression_algorithm_name_import;
 #define grpc_compression_algorithm_name grpc_compression_algorithm_name_import
-typedef grpc_compression_algorithm(*grpc_compression_algorithm_for_level_type)(grpc_compression_level level, uint32_t accepted_encodings);
-extern grpc_compression_algorithm_for_level_type grpc_compression_algorithm_for_level_import;
-#define grpc_compression_algorithm_for_level grpc_compression_algorithm_for_level_import
 typedef void(*grpc_compression_options_init_type)(grpc_compression_options *opts);
 extern grpc_compression_options_init_type grpc_compression_options_init_import;
 #define grpc_compression_options_init grpc_compression_options_init_import