Merge branch 'master' of github.com:grpc/grpc into cpp_auth_md_processor

16 files changed, 405 insertions, 46 deletions

diff --git a/BUILD b/BUILD
index bc2136dabe..318959333e 100644
--- a/BUILD
+++ b/BUILD
@@ -386,7 +386,9 @@ cc_library(
     "src/core/transport/transport_op_string.c",
     "src/core/census/context.c",
     "src/core/census/initialize.c",
+    "src/core/census/operation.c",
     "src/core/census/record_stat.c",
+    "src/core/census/tracing.c",
   ],
   hdrs = [
     "include/grpc/grpc_security.h",
@@ -634,7 +636,9 @@ cc_library(
     "src/core/transport/transport_op_string.c",
     "src/core/census/context.c",
     "src/core/census/initialize.c",
+    "src/core/census/operation.c",
     "src/core/census/record_stat.c",
+    "src/core/census/tracing.c",
   ],
   hdrs = [
     "include/grpc/byte_buffer.h",
@@ -1146,7 +1150,9 @@ objc_library(
     "src/core/transport/transport_op_string.c",
     "src/core/census/context.c",
     "src/core/census/initialize.c",
+    "src/core/census/operation.c",
     "src/core/census/record_stat.c",
+    "src/core/census/tracing.c",
   ],
   hdrs = [
     "include/grpc/grpc_security.h",
diff --git a/Makefile b/Makefile
index 4c4a5b2538..4384469055 100644
--- a/Makefile
+++ b/Makefile
@@ -4149,7 +4149,9 @@ LIBGRPC_SRC = \
     src/core/transport/transport_op_string.c \
     src/core/census/context.c \
     src/core/census/initialize.c \
+    src/core/census/operation.c \
     src/core/census/record_stat.c \
+    src/core/census/tracing.c \
 
 PUBLIC_HEADERS_C += \
     include/grpc/grpc_security.h \
@@ -4423,7 +4425,9 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/transport/transport_op_string.c \
     src/core/census/context.c \
     src/core/census/initialize.c \
+    src/core/census/operation.c \
     src/core/census/record_stat.c \
+    src/core/census/tracing.c \
 
 PUBLIC_HEADERS_C += \
     include/grpc/byte_buffer.h \
diff --git a/build.json b/build.json
index daa0178e35..7db50a9361 100644
--- a/build.json
+++ b/build.json
@@ -24,7 +24,9 @@
       "src": [
         "src/core/census/context.c",
         "src/core/census/initialize.c",
-        "src/core/census/record_stat.c"
+        "src/core/census/operation.c",
+        "src/core/census/record_stat.c",
+        "src/core/census/tracing.c"
       ]
     },
     {
diff --git a/gRPC.podspec b/gRPC.podspec
index 55f72c93d8..0349d04c6a 100644
--- a/gRPC.podspec
+++ b/gRPC.podspec
@@ -395,7 +395,9 @@ Pod::Spec.new do |s|
                       'src/core/transport/transport_op_string.c',
                       'src/core/census/context.c',
                       'src/core/census/initialize.c',
-                      'src/core/census/record_stat.c'
+                      'src/core/census/operation.c',
+                      'src/core/census/record_stat.c',
+                      'src/core/census/tracing.c'
 
     ss.private_header_files = 'src/core/support/env.h',
                               'src/core/support/file.h',
diff --git a/include/grpc/census.h b/include/grpc/census.h
index a18b997b79..d1a2978bd2 100644
--- a/include/grpc/census.h
+++ b/include/grpc/census.h
@@ -69,12 +69,14 @@ int census_supported(void);
 /** Return the census features currently enabled. */
 int census_enabled(void);
 
-/* Internally, Census relies on a context, which should be propagated across
- * RPC's. From the RPC subsystems viewpoint, this is an opaque data structure.
- * A context must be used as the first argument to all other census
- * functions. Conceptually, contexts should be thought of as specific to
- * single RPC/thread. The context can be serialized for passing across the
- * wire. */
+/**
+  Context is a handle used by census to represent the current tracing and
+  tagging information. Contexts should be propagated across RPC's. Contexts
+  are created by any of the census_start_*_op() functions. A context is
+  typically used as argument to most census functions. Conceptually, contexts
+  should be thought of as specific to single RPC/thread. The context can be
+  serialized for passing across the wire, via census_context_serialize().
+*/
 typedef struct census_context census_context;
 
 /* This function is called by the RPC subsystem whenever it needs to get a
@@ -91,18 +93,236 @@ typedef struct census_context census_context;
 size_t census_context_serialize(const census_context *context, char *buffer,
                                 size_t buf_size);
 
-/* Create a new census context, possibly from a serialized buffer. If 'buffer'
- * is non-NULL, it is assumed that it is a buffer encoded by
- * census_context_serialize(). If `buffer` is NULL, a new, empty context is
- * created. The decoded/new contest is returned in 'context'.
- *
- * Returns 0 if no errors, non-zero if buffer is incorrectly formatted, in
- * which case a new empty context will be returned. */
-int census_context_deserialize(const char *buffer, census_context **context);
+/* Distributed traces can have a number of options. */
+enum census_trace_mask_values {
+  CENSUS_TRACE_MASK_NONE = 0,      /* Default, empty flags */
+  CENSUS_TRACE_MASK_IS_SAMPLED = 1 /* RPC tracing enabled for this context. */
+};
+
+/** Get the current trace mask associated with this context. The value returned
+    will be the logical or of census_trace_mask_values values. */
+int census_trace_mask(const census_context *context);
+
+/** Set the trace mask associated with a context. */
+void census_set_trace_mask(int trace_mask);
+
+/* The concept of "operation" is a fundamental concept for Census. In an RPC
+   system, and operation typcially represents a single RPC, or a significant
+   sub-part thereof (e.g. a single logical "read" RPC to a distributed storage
+   system might do several other actions in parallel, from looking up metadata
+   indices to making requests of other services - each of these could be a
+   sub-operation with the larger RPC operation). Census uses operations for the
+   following:
+
+   CPU accounting: If enabled, census will measure the thread CPU time
+   consumed between operation start and end times.
+
+   Active operations: Census will maintain information on all currently
+   active operations.
+
+   Distributed tracing: Each operation serves as a logical trace span.
+
+   Stats collection: Stats are broken down by operation (e.g. latency
+   breakdown for each unique RPC path).
+
+   The following functions serve to delineate the start and stop points for
+   each logical operation. */
+
+/**
+  This structure represents a timestamp as used by census to record the time
+  at which an operation begins.
+*/
+typedef struct {
+  /* Use gpr_timespec for default implementation. High performance
+   * implementations should use a cycle-counter based timestamp. */
+  gpr_timespec ts;
+} census_timestamp;
+
+/**
+  Mark the beginning of an RPC operation. The information required to call the
+  functions to record the start of RPC operations (both client and server) may
+  not be callable at the true start time of the operation, due to information
+  not being available (e.g. the census context data will not be available in a
+  server RPC until at least initial metadata has been processed). To ensure
+  correct CPU accounting and latency recording, RPC systems can call this
+  function to get the timestamp of operation beginning. This can later be used
+  as an argument to census_start_{client,server}_rpc_op(). NB: for correct
+  CPU accounting, the system must guarantee that the same thread is used
+  for all request processing after this function is called.
+
+  @return A timestamp representing the operation start time.
+*/
+census_timestamp census_start_rpc_op_timestamp(void);
+
+/**
+  Represent functions to map RPC name ID to service/method names. Census
+  breaks down all RPC stats by service and method names. We leave the
+  definition and format of these to the RPC system. For efficiency purposes,
+  we encode these as a single 64 bit identifier, and allow the RPC system to
+  provide a structure for functions that can convert these to service and
+  method strings.
+
+  TODO(aveitch): Instead of providing this as an argument to the rpc_start_op()
+  functions, maybe it should be set once at census initialization.
+*/
+typedef struct {
+  const char *(*get_rpc_service_name)(gpr_int64 id);
+  const char *(*get_rpc_method_name)(gpr_int64 id);
+} census_rpc_name_info;
+
+/**
+   Start a client rpc operation. This function should be called as early in the
+   client RPC path as possible. This function will create a new context. If
+   the context argument is non-null, then the new context will inherit all
+   its properties, with the following changes:
+   - create a new operation ID for the new context, marking it as a child of
+     the previous operation.
+   - use the new RPC path and peer information for tracing and stats
+     collection purposes, rather than those from the original context
+
+   If the context argument is NULL, then a new root context is created. This
+   is particularly important for tracing purposes (the trace spans generated
+   will be unassociated with any other trace spans, except those
+   downstream). The trace_mask will be used for tracing operations associated
+   with the new context.
+
+   In some RPC systems (e.g. where load balancing is used), peer information
+   may not be available at the time the operation starts. In this case, use a
+   NULL value for peer, and set it later using the
+   census_set_rpc_client_peer() function.
+
+   @param context The parent context. Can be NULL.
+   @param rpc_name_id The rpc name identifier to be associated with this RPC.
+   @param rpc_name_info Used to decode rpc_name_id.
+   @param peer RPC peer. If not available at the time, NULL can be used,
+               and a later census_set_rpc_client_peer() call made.
+   @param trace_mask An OR of census_trace_mask_values values. Only used in
+                     the creation of a new root context (context == NULL).
+   @param start_time A timestamp returned from census_start_rpc_op_timestamp().
+                     Can be NULL. Used to set the true time the operation
+                     begins.
+
+   @return A new census context.
+ */
+census_context *census_start_client_rpc_op(
+    const census_context *context, gpr_int64 rpc_name_id,
+    const census_rpc_name_info *rpc_name_info, const char *peer, int trace_mask,
+    const census_timestamp *start_time);
+
+/**
+  Add peer information to a context representing a client RPC operation.
+*/
+void census_set_rpc_client_peer(census_context *context, const char *peer);
+
+/**
+   Start a server RPC operation. Returns a new context to be used in future
+   census calls. If buffer is non-NULL, then the buffer contents should
+   represent the client context, as generated by census_context_serialize().
+   If buffer is NULL, a new root context is created.
+
+   @param buffer Buffer containing bytes output from census_context_serialize().
+   @param rpc_name_id The rpc name identifier to be associated with this RPC.
+   @param rpc_name_info Used to decode rpc_name_id.
+   @param peer RPC peer.
+   @param trace_mask An OR of census_trace_mask_values values. Only used in
+                     the creation of a new root context (buffer == NULL).
+   @param start_time A timestamp returned from census_start_rpc_op_timestamp().
+                     Can be NULL. Used to set the true time the operation
+                     begins.
+
+   @return A new census context.
+ */
+census_context *census_start_server_rpc_op(
+    const char *buffer, gpr_int64 rpc_name_id,
+    const census_rpc_name_info *rpc_name_info, const char *peer, int trace_mask,
+    census_timestamp *start_time);
+
+/**
+   Start a new, non-RPC operation. In general, this function works very
+   similarly to census_start_client_rpc_op, with the primary difference being
+   the replacement of host/path information with the more generic family/name
+   tags. If the context argument is non-null, then the new context will
+   inherit all its properties, with the following changes:
+   - create a new operation ID for the new context, marking it as a child of
+     the previous operation.
+   - use the family and name information for tracing and stats collection
+     purposes, rather than those from the original context
+
+   If the context argument is NULL, then a new root context is created. This
+   is particularly important for tracing purposes (the trace spans generated
+   will be unassociated with any other trace spans, except those
+   downstream). The trace_mask will be used for tracing
+   operations associated with the new context.
+
+   @param context The base context. Can be NULL.
+   @param family Family name to associate with the trace
+   @param name Name within family to associated with traces/stats
+   @param trace_mask An OR of census_trace_mask_values values. Only used if
+                     context is NULL.
+
+   @return A new census context.
+ */
+census_context *census_start_op(census_context *context, const char *family,
+                                const char *name, int trace_mask);
+
+/**
+  End an operation started by any of the census_start_*_op*() calls. The
+  context used in this call will no longer be valid once this function
+  completes.
+
+  @param context Context associated with operation which is ending.
+  @param status status associated with the operation. Not interpreted by
+                census.
+*/
+void census_end_op(census_context *context, int status);
+
+#define CENSUS_TRACE_RECORD_START_OP ((gpr_uint32)0)
+#define CENSUS_TRACE_RECORD_END_OP ((gpr_uint32)1)
+
+/** Insert a trace record into the trace stream. The record consists of an
+    arbitrary size buffer, the size of which is provided in 'n'.
+    @param context Trace context
+    @param type User-defined type to associate with trace entry.
+    @param buffer Pointer to buffer to use
+    @param n Number of bytes in buffer
+*/
+void census_trace_print(census_context *context, gpr_uint32 type,
+                        const char *buffer, size_t n);
+
+/** Trace record. */
+typedef struct {
+  census_timestamp timestamp; /* Time of record creation */
+  gpr_uint64 trace_id;        /* Trace ID associated with record */
+  gpr_uint64 op_id;           /* Operation ID associated with record */
+  gpr_uint32 type;            /* Type (as used in census_trace_print() */
+  const char *buffer;         /* Buffer (from census_trace_print() */
+  size_t buf_size;            /* Number of bytes inside buffer */
+} census_trace_record;
+
+/** Start a scan of existing trace records. While a scan is ongoing, addition
+    of new trace records will be blocked if the underlying trace buffers
+    fill up, so trace processing systems should endeavor to complete
+    reading as soon as possible.
+  @param consume if non-zero, indicates that reading records also "consumes"
+         the previously read record - i.e. releases space in the trace log
+         while scanning is ongoing.
+  @returns 0 on success, non-zero on failure (e.g. if a scan is already ongoing)
+*/
+int census_trace_scan_start(int consume);
+
+/** Get a trace record. The data pointed to by the trace buffer is guaranteed
+    stable until the next census_get_trace_record() call (if the consume
+    argument to census_trace_scan_start was non-zero) or census_trace_scan_end()
+    is called (otherwise).
+  @param trace_record structure that will be filled in with oldest trace record.
+  @returns -1 if an error occurred (e.g. no previous call to
+           census_trace_scan_start()), 0 if there is no more trace data (and
+           trace_record will not be modified) or 1 otherwise.
+*/
+int census_get_trace_record(census_trace_record *trace_record);
 
-/* The given context is destroyed. Once destroyed, using the context in
- * future census calls will result in undefined behavior. */
-void census_context_destroy(census_context *context);
+/** End a scan previously started by census_trace_scan_start() */
+void census_trace_scan_end();
 
 /* Max number of characters in tag key */
 #define CENSUS_MAX_TAG_KEY_LENGTH 20
diff --git a/src/core/census/context.c b/src/core/census/context.c
index df238ec98c..cab58b653c 100644
--- a/src/core/census/context.c
+++ b/src/core/census/context.c
@@ -44,16 +44,3 @@ size_t census_context_serialize(const census_context *context, char *buffer,
   /* TODO(aveitch): implement serialization */
   return 0;
 }
-
-int census_context_deserialize(const char *buffer, census_context **context) {
-  int ret = 0;
-  if (buffer != NULL) {
-    /* TODO(aveitch): implement deserialization. */
-    ret = 1;
-  }
-  *context = gpr_malloc(sizeof(census_context));
-  memset(*context, 0, sizeof(census_context));
-  return ret;
-}
-
-void census_context_destroy(census_context *context) { gpr_free(context); }
diff --git a/src/core/census/grpc_context.c b/src/core/census/grpc_context.c
index 11f1eb3d5d..429f3ec9db 100644
--- a/src/core/census/grpc_context.c
+++ b/src/core/census/grpc_context.c
@@ -35,24 +35,11 @@
 #include <grpc/grpc.h>
 #include "src/core/surface/call.h"
 
-static void grpc_census_context_destroy(void *context) {
-  census_context_destroy((census_context *)context);
-}
-
 void grpc_census_call_set_context(grpc_call *call, census_context *context) {
   if (census_enabled() == CENSUS_FEATURE_NONE) {
     return;
   }
-  if (context == NULL) {
-    if (grpc_call_is_client(call)) {
-      census_context *context_ptr;
-      census_context_deserialize(NULL, &context_ptr);
-      grpc_call_context_set(call, GRPC_CONTEXT_TRACING, context_ptr,
-                            grpc_census_context_destroy);
-    } else {
-      /* TODO(aveitch): server side context code to be implemented. */
-    }
-  } else {
+  if (context != NULL) {
     grpc_call_context_set(call, GRPC_CONTEXT_TRACING, context, NULL);
   }
 }
diff --git a/src/core/census/operation.c b/src/core/census/operation.c
new file mode 100644
index 0000000000..118eb0a47a
--- /dev/null
+++ b/src/core/census/operation.c
@@ -0,0 +1,63 @@
+/*
+ * 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 <grpc/census.h>
+
+/* TODO(aveitch): These are all placeholder implementations. */
+
+census_timestamp census_start_rpc_op_timestamp(void) {
+  census_timestamp ct;
+  /* TODO(aveitch): assumes gpr_timespec implementation of census_timestamp. */
+  ct.ts = gpr_now(GPR_CLOCK_MONOTONIC);
+  return ct;
+}
+
+census_context *census_start_client_rpc_op(
+    const census_context *context, gpr_int64 rpc_name_id,
+    const census_rpc_name_info *rpc_name_info, const char *peer, int trace_mask,
+    const census_timestamp *start_time) {
+  return NULL;
+}
+
+census_context *census_start_server_rpc_op(
+    const char *buffer, gpr_int64 rpc_name_id,
+    const census_rpc_name_info *rpc_name_info, const char *peer, int trace_mask,
+    census_timestamp *start_time) {
+  return NULL;
+}
+
+census_context *census_start_op(census_context *context, const char *family,
+                                const char *name, int trace_mask) {
+  return NULL;
+}
+
+void census_end_op(census_context *context, int status) {}
diff --git a/src/core/census/tracing.c b/src/core/census/tracing.c
new file mode 100644
index 0000000000..ae38773c0a
--- /dev/null
+++ b/src/core/census/tracing.c
@@ -0,0 +1,45 @@
+/*
+ *
+ * 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 <grpc/census.h>
+
+/* TODO(aveitch): These are all placeholder implementations. */
+
+int census_trace_mask(const census_context *context) {
+  return CENSUS_TRACE_MASK_NONE;
+}
+
+void census_set_trace_mask(int trace_mask) {}
+
+void census_trace_print(census_context *context, gpr_uint32 type,
+                        const char *buffer, size_t n) {}
diff --git a/src/csharp/README.md b/src/csharp/README.md
index 30523b3bd2..3fbc1c5f05 100644
--- a/src/csharp/README.md
+++ b/src/csharp/README.md
@@ -158,3 +158,20 @@ Contents
   An example client that sends some requests to math server.
 - Grpc.IntegrationTesting:
   Cross-language gRPC implementation testing (interop testing).
+
+Troubleshooting
+---------------
+
+### Problem: Unable to load DLL 'grpc_csharp_ext.dll'
+
+Internally, gRPC C# uses a native library written in C (gRPC C core) and invokes its functionality via P/Invoke. `grpc_csharp_ext` library is a native extension library that facilitates this by wrapping some C core API into a form that's more digestible for P/Invoke. If you get the above error, it means that the native dependencies could not be located by the C# runtime (or they are incompatible with the current runtime, so they could not be loaded). The solution to this is environment specific.
+
+- If you are developing on Windows in Visual Studio, the `grpc_csharp_ext.dll` that is shipped by gRPC nuget packages should be automatically copied to your build destination folder once you build. By adjusting project properties in your VS project file, you can influence which exact configuration of `grpc_csharp_ext.dll` will be used (based on VS version, bitness, debug/release configuration).
+
+- If you are running your application that is using gRPC on Windows machine that doesn't have Visual Studio installed, you might need to install [Visual C++ 2013 redistributable](https://www.microsoft.com/en-us/download/details.aspx?id=40784) that contains some system .dll libraries that `grpc_csharp_ext.dll` depends on (see #905 for more details).
+
+- On Linux (or Docker), you need to first install gRPC C core and `libgrpc_csharp_ext.so` shared libraries. Currently, the libraries can be installed by `make install_grpc_csharp_ext` or using Linuxbrew (a Debian package is coming soon). Installation on a machine where your application is going to be deployed is no different. 
+
+- On Mac, you need to first install gRPC C core and `libgrpc_csharp_ext.dylib` shared libraries using Homebrew. See above for installation instruction. Installation on a machine where your application is going to be deployed is no different. 
+
+- Possible cause for the problem is that the `grpc_csharp_ext` library is installed, but it has different bitness (32/64bit) than your C# runtime (in case you are using mono) or C# application.
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index 7d5df66bc1..0b7f89ffdd 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -1022,7 +1022,9 @@ src/core/transport/transport.c \
 src/core/transport/transport_op_string.c \
 src/core/census/context.c \
 src/core/census/initialize.c \
+src/core/census/operation.c \
 src/core/census/record_stat.c \
+src/core/census/tracing.c \
 include/grpc/support/alloc.h \
 include/grpc/support/atm.h \
 include/grpc/support/atm_gcc_atomic.h \
diff --git a/tools/run_tests/sources_and_headers.json b/tools/run_tests/sources_and_headers.json
index 4840e24463..c91220948d 100644
--- a/tools/run_tests/sources_and_headers.json
+++ b/tools/run_tests/sources_and_headers.json
@@ -12362,8 +12362,10 @@
       "src/core/census/grpc_filter.c", 
       "src/core/census/grpc_filter.h", 
       "src/core/census/initialize.c", 
+      "src/core/census/operation.c", 
       "src/core/census/record_stat.c", 
       "src/core/census/rpc_stat_id.h", 
+      "src/core/census/tracing.c", 
       "src/core/channel/channel_args.c", 
       "src/core/channel/channel_args.h", 
       "src/core/channel/channel_stack.c", 
@@ -12825,8 +12827,10 @@
       "src/core/census/grpc_filter.c", 
       "src/core/census/grpc_filter.h", 
       "src/core/census/initialize.c", 
+      "src/core/census/operation.c", 
       "src/core/census/record_stat.c", 
       "src/core/census/rpc_stat_id.h", 
+      "src/core/census/tracing.c", 
       "src/core/channel/channel_args.c", 
       "src/core/channel/channel_args.h", 
       "src/core/channel/channel_stack.c", 
diff --git a/vsprojects/grpc/grpc.vcxproj b/vsprojects/grpc/grpc.vcxproj
index 1fa7e4b4f1..f85216151b 100644
--- a/vsprojects/grpc/grpc.vcxproj
+++ b/vsprojects/grpc/grpc.vcxproj
@@ -625,8 +625,12 @@
     </ClCompile>
     <ClCompile Include="..\..\src\core\census\initialize.c">
     </ClCompile>
+    <ClCompile Include="..\..\src\core\census\operation.c">
+    </ClCompile>
     <ClCompile Include="..\..\src\core\census\record_stat.c">
     </ClCompile>
+    <ClCompile Include="..\..\src\core\census\tracing.c">
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\gpr\gpr.vcxproj">
diff --git a/vsprojects/grpc/grpc.vcxproj.filters b/vsprojects/grpc/grpc.vcxproj.filters
index b22818aebd..835aa1b165 100644
--- a/vsprojects/grpc/grpc.vcxproj.filters
+++ b/vsprojects/grpc/grpc.vcxproj.filters
@@ -418,9 +418,15 @@
     <ClCompile Include="..\..\src\core\census\initialize.c">
       <Filter>src\core\census</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\core\census\operation.c">
+      <Filter>src\core\census</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\src\core\census\record_stat.c">
       <Filter>src\core\census</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\core\census\tracing.c">
+      <Filter>src\core\census</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\include\grpc\grpc_security.h">
diff --git a/vsprojects/grpc_unsecure/grpc_unsecure.vcxproj b/vsprojects/grpc_unsecure/grpc_unsecure.vcxproj
index 3883a328e0..ca73b5633a 100644
--- a/vsprojects/grpc_unsecure/grpc_unsecure.vcxproj
+++ b/vsprojects/grpc_unsecure/grpc_unsecure.vcxproj
@@ -568,8 +568,12 @@
     </ClCompile>
     <ClCompile Include="..\..\src\core\census\initialize.c">
     </ClCompile>
+    <ClCompile Include="..\..\src\core\census\operation.c">
+    </ClCompile>
     <ClCompile Include="..\..\src\core\census\record_stat.c">
     </ClCompile>
+    <ClCompile Include="..\..\src\core\census\tracing.c">
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\gpr\gpr.vcxproj">
diff --git a/vsprojects/grpc_unsecure/grpc_unsecure.vcxproj.filters b/vsprojects/grpc_unsecure/grpc_unsecure.vcxproj.filters
index d12abc0ad7..994539cfa2 100644
--- a/vsprojects/grpc_unsecure/grpc_unsecure.vcxproj.filters
+++ b/vsprojects/grpc_unsecure/grpc_unsecure.vcxproj.filters
@@ -358,9 +358,15 @@
     <ClCompile Include="..\..\src\core\census\initialize.c">
       <Filter>src\core\census</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\core\census\operation.c">
+      <Filter>src\core\census</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\src\core\census\record_stat.c">
       <Filter>src\core\census</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\core\census\tracing.c">
+      <Filter>src\core\census</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\include\grpc\byte_buffer.h">