SERVER-27211 de-duplicate symbol `isMongos`

A hidden global variable representing the "is Mongos process" state
can now be accessed and updated by the `is_mongos.h` interface.  All
tests defining their own versions (and test crutches) are replaced
with calls to global registration of the desired state of this variable.
The `mongos` main executable now sets this hidden global state as part
of its startup code.

21 files changed, 48 insertions, 100 deletions

diff --git a/src/mongo/db/pipeline/SConscript b/src/mongo/db/pipeline/SConscript
index 3aeea52b08c..ac7ab097c07 100644
--- a/src/mongo/db/pipeline/SConscript
+++ b/src/mongo/db/pipeline/SConscript
@@ -143,6 +143,7 @@ env.CppUnitTest(
         '$BUILD_DIR/mongo/db/auth/authorization_manager_mock_init',
         '$BUILD_DIR/mongo/db/query/query_test_service_context',
         '$BUILD_DIR/mongo/db/service_context',
+        '$BUILD_DIR/mongo/s/is_mongos',
         '$BUILD_DIR/mongo/util/clock_source_mock',
     ],
 )
@@ -302,6 +303,7 @@ env.CppUnitTest(
         '$BUILD_DIR/mongo/db/auth/authorization_manager_mock_init',
         '$BUILD_DIR/mongo/db/query/query_test_service_context',
         '$BUILD_DIR/mongo/db/service_context_noop_init',
+        '$BUILD_DIR/mongo/s/is_mongos',
     ],
 )
 
@@ -325,6 +327,7 @@ env.CppUnitTest(
         '$BUILD_DIR/mongo/db/auth/authorization_manager_mock_init',
         '$BUILD_DIR/mongo/db/query/query_test_service_context',
         '$BUILD_DIR/mongo/db/service_context_noop_init',
+        '$BUILD_DIR/mongo/s/is_mongos',
         'document_source_facet',
         'document_value_test_util',
     ],
@@ -336,6 +339,7 @@ env.CppUnitTest(
     LIBDEPS=[
         '$BUILD_DIR/mongo/db/auth/authorization_manager_mock_init',
         '$BUILD_DIR/mongo/db/service_context_noop_init',
+        '$BUILD_DIR/mongo/s/is_mongos',
         'document_source_facet',
         'document_value_test_util',
     ],
@@ -373,6 +377,7 @@ env.CppUnitTest(
         '$BUILD_DIR/mongo/db/query/query_test_service_context',
         '$BUILD_DIR/mongo/db/service_context',
         '$BUILD_DIR/mongo/db/service_context_noop_init',
+        '$BUILD_DIR/mongo/s/is_mongos',
         'document_value_test_util',
         'document_source_lookup',
         'pipeline',
diff --git a/src/mongo/db/pipeline/document_source_facet_test.cpp b/src/mongo/db/pipeline/document_source_facet_test.cpp
index 72d79fd56fe..733634b8994 100644
--- a/src/mongo/db/pipeline/document_source_facet_test.cpp
+++ b/src/mongo/db/pipeline/document_source_facet_test.cpp
@@ -50,11 +50,6 @@ namespace mongo {
 using std::deque;
 using std::vector;
 
-// Crutch.
-bool isMongos() {
-    return false;
-}
-
 namespace {
 
 using std::deque;
diff --git a/src/mongo/db/pipeline/document_source_graph_lookup_test.cpp b/src/mongo/db/pipeline/document_source_graph_lookup_test.cpp
index ddddfe5f5a9..f96e3521017 100644
--- a/src/mongo/db/pipeline/document_source_graph_lookup_test.cpp
+++ b/src/mongo/db/pipeline/document_source_graph_lookup_test.cpp
@@ -43,11 +43,6 @@
 
 namespace mongo {
 
-// Crutch.
-bool isMongos() {
-    return false;
-}
-
 namespace {
 
 // This provides access to getExpCtx(), but we'll use a different name for this test suite.
diff --git a/src/mongo/db/pipeline/document_source_sort_test.cpp b/src/mongo/db/pipeline/document_source_sort_test.cpp
index 52da88fd616..233e200f374 100644
--- a/src/mongo/db/pipeline/document_source_sort_test.cpp
+++ b/src/mongo/db/pipeline/document_source_sort_test.cpp
@@ -49,11 +49,6 @@
 
 namespace mongo {
 
-// Crutch.
-bool isMongos() {
-    return false;
-}
-
 namespace {
 
 using boost::intrusive_ptr;
diff --git a/src/mongo/db/pipeline/pipeline_test.cpp b/src/mongo/db/pipeline/pipeline_test.cpp
index 7b4331d60b8..41cd6e567d3 100644
--- a/src/mongo/db/pipeline/pipeline_test.cpp
+++ b/src/mongo/db/pipeline/pipeline_test.cpp
@@ -46,12 +46,6 @@
 #include "mongo/db/query/query_test_service_context.h"
 #include "mongo/dbtests/dbtests.h"
 
-namespace mongo {
-bool isMongos() {
-    return false;
-}
-}
-
 namespace PipelineTests {
 
 using boost::intrusive_ptr;
diff --git a/src/mongo/db/pipeline/tee_buffer_test.cpp b/src/mongo/db/pipeline/tee_buffer_test.cpp
index 0a8fc7d22a2..2e4495c3d5f 100644
--- a/src/mongo/db/pipeline/tee_buffer_test.cpp
+++ b/src/mongo/db/pipeline/tee_buffer_test.cpp
@@ -37,12 +37,6 @@
 #include "mongo/util/assert_util.h"
 
 namespace mongo {
-
-// Crutch.
-bool isMongos() {
-    return false;
-}
-
 namespace {
 
 TEST(TeeBufferTest, ShouldRequireAtLeastOneConsumer) {
diff --git a/src/mongo/db/s/SConscript b/src/mongo/db/s/SConscript
index 53e74c1d5e3..e9c17720d76 100644
--- a/src/mongo/db/s/SConscript
+++ b/src/mongo/db/s/SConscript
@@ -69,6 +69,7 @@ env.Library(
         '$BUILD_DIR/mongo/bson/util/bson_extract',
         '$BUILD_DIR/mongo/db/common',
         '$BUILD_DIR/mongo/s/sharding_initialization',
+        '$BUILD_DIR/mongo/s/is_mongos',
         'metadata',
         'migration_types',
         'type_shard_identity',
diff --git a/src/mongo/db/s/sharding_state.cpp b/src/mongo/db/s/sharding_state.cpp
index bd6867ddc6d..f9785b5325d 100644
--- a/src/mongo/db/s/sharding_state.cpp
+++ b/src/mongo/db/s/sharding_state.cpp
@@ -818,12 +818,4 @@ void ShardingState::_initializeRangeDeleterTaskExecutor() {
 executor::ThreadPoolTaskExecutor* ShardingState::getRangeDeleterTaskExecutor() {
     return _rangeDeleterTaskExecutor.get();
 }
-
-/**
- * Global free function.
- */
-bool isMongos() {
-    return false;
-}
-
 }  // namespace mongo
diff --git a/src/mongo/db/sorter/SConscript b/src/mongo/db/sorter/SConscript
index 959f6cdb919..365c1a91f54 100644
--- a/src/mongo/db/sorter/SConscript
+++ b/src/mongo/db/sorter/SConscript
@@ -7,4 +7,5 @@ sorterEnv.CppUnitTest('sorter_test',
                        LIBDEPS=['$BUILD_DIR/mongo/db/service_context',
                                 '$BUILD_DIR/mongo/db/storage/wiredtiger/storage_wiredtiger_customization_hooks',
                                 '$BUILD_DIR/mongo/db/storage/storage_options',
+                                '$BUILD_DIR/mongo/s/is_mongos',
                                 '$BUILD_DIR/third_party/shim_snappy'])
diff --git a/src/mongo/db/sorter/sorter_test.cpp b/src/mongo/db/sorter/sorter_test.cpp
index 19171fb13ba..1bf02fdcbf3 100644
--- a/src/mongo/db/sorter/sorter_test.cpp
+++ b/src/mongo/db/sorter/sorter_test.cpp
@@ -52,12 +52,6 @@ using namespace mongo::sorter;
 using std::make_shared;
 using std::pair;
 
-// Stub to avoid including the server_options library
-// TODO: This should go away once we can do these checks at compile time
-bool isMongos() {
-    return false;
-}
-
 // Stub to avoid including the server environment library.
 MONGO_INITIALIZER(SetGlobalEnvironment)(InitializerContext* context) {
     setGlobalServiceContext(stdx::make_unique<ServiceContextNoop>());
diff --git a/src/mongo/db/views/SConscript b/src/mongo/db/views/SConscript
index 5ba5607297a..fc5ba8b83a1 100644
--- a/src/mongo/db/views/SConscript
+++ b/src/mongo/db/views/SConscript
@@ -39,7 +39,6 @@ env.CppUnitTest(
         'resolved_view_test.cpp',
         'view_catalog_test.cpp',
         'view_definition_test.cpp',
-        'view_test_crutch.cpp'
     ],
     LIBDEPS=[
         'views',
@@ -47,6 +46,7 @@ env.CppUnitTest(
         '$BUILD_DIR/mongo/db/query/collation/collator_interface_mock',
         '$BUILD_DIR/mongo/db/query/query_test_service_context',
         '$BUILD_DIR/mongo/db/service_context_noop_init',
+        '$BUILD_DIR/mongo/s/is_mongos',
         '$BUILD_DIR/mongo/unittest/unittest',
     ],
 )
diff --git a/src/mongo/db/views/resolved_view_test.cpp b/src/mongo/db/views/resolved_view_test.cpp
index f47b980fba1..2221704e69a 100644
--- a/src/mongo/db/views/resolved_view_test.cpp
+++ b/src/mongo/db/views/resolved_view_test.cpp
@@ -36,7 +36,6 @@
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/pipeline/aggregation_request.h"
 #include "mongo/db/views/resolved_view.h"
-#include "mongo/db/views/view_test_crutch.h"
 #include "mongo/unittest/unittest.h"
 
 namespace mongo {
diff --git a/src/mongo/db/views/view_catalog_test.cpp b/src/mongo/db/views/view_catalog_test.cpp
index 4c93b7d1d18..1a034533a58 100644
--- a/src/mongo/db/views/view_catalog_test.cpp
+++ b/src/mongo/db/views/view_catalog_test.cpp
@@ -45,7 +45,6 @@
 #include "mongo/db/views/view.h"
 #include "mongo/db/views/view_catalog.h"
 #include "mongo/db/views/view_graph.h"
-#include "mongo/db/views/view_test_crutch.h"
 #include "mongo/stdx/functional.h"
 #include "mongo/stdx/memory.h"
 #include "mongo/unittest/unittest.h"
diff --git a/src/mongo/db/views/view_definition_test.cpp b/src/mongo/db/views/view_definition_test.cpp
index e61ddaa1b8d..b815324b687 100644
--- a/src/mongo/db/views/view_definition_test.cpp
+++ b/src/mongo/db/views/view_definition_test.cpp
@@ -37,7 +37,6 @@
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/query/collation/collator_interface_mock.h"
 #include "mongo/db/views/view.h"
-#include "mongo/db/views/view_test_crutch.h"
 #include "mongo/stdx/memory.h"
 #include "mongo/unittest/death_test.h"
 #include "mongo/unittest/unittest.h"
diff --git a/src/mongo/db/views/view_test_crutch.cpp b/src/mongo/db/views/view_test_crutch.cpp
deleted file mode 100644
index ac4434c1911..00000000000
--- a/src/mongo/db/views/view_test_crutch.cpp
+++ /dev/null
@@ -1,35 +0,0 @@
-/**
- *    Copyright (C) 2016 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#include "mongo/db/views/view_test_crutch.h"
-
-namespace mongo {
-bool isMongos() {
-    return false;
-}
-}  // namespace mongo
diff --git a/src/mongo/s/SConscript b/src/mongo/s/SConscript
index 2ccbe5b43e4..80fc2930396 100644
--- a/src/mongo/s/SConscript
+++ b/src/mongo/s/SConscript
@@ -273,6 +273,14 @@ env.Library(
 )
 
 env.Library(
+    target='is_mongos',
+    source=[
+        'is_mongos.cpp',
+    ],
+    LIBDEPS=[],
+)
+
+env.Library(
     target='mongoscore',
     source=[
         'chunk_manager_targeter.cpp',
@@ -292,6 +300,7 @@ env.Library(
         '$BUILD_DIR/mongo/s/query/cluster_query',
         '$BUILD_DIR/mongo/util/concurrency/task',
         'cluster_last_error_info',
+        'is_mongos',
         'write_ops/cluster_write_op',
         'write_ops/cluster_write_op_conversion',
     ],
diff --git a/src/mongo/s/is_mongos.cpp b/src/mongo/s/is_mongos.cpp
new file mode 100644
index 00000000000..cef0d4c57ef
--- /dev/null
+++ b/src/mongo/s/is_mongos.cpp
@@ -0,0 +1,15 @@
+#include "mongo/s/is_mongos.h"
+
+namespace mongo {
+namespace {
+bool mongosState = false;
+}  // namespace
+}  // namespace mongo
+
+bool mongo::isMongos() {
+    return mongosState;
+}
+
+void mongo::setMongos(const bool state) {
+    mongosState = state;
+}
diff --git a/src/mongo/db/views/view_test_crutch.h b/src/mongo/s/is_mongos.h
index 8304a29e342..8c3593e599f 100644
--- a/src/mongo/db/views/view_test_crutch.h
+++ b/src/mongo/s/is_mongos.h
@@ -1,5 +1,5 @@
-/**
- *    Copyright (C) 2016 MongoDB Inc.
+/*
+ *    Copyright (C) 2016 10gen Inc.
  *
  *    This program is free software: you can redistribute it and/or  modify
  *    it under the terms of the GNU Affero General Public License, version 3,
@@ -17,20 +17,21 @@
  *    code of portions of this program with the OpenSSL library under certain
  *    conditions as described in each individual source file and distribute
  *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
+ *    must comply with the GNU Affero General Public License in all respects
+ *    for all of the code used other than as permitted herein. If you modify
+ *    file(s) with this exception, you may extend this exception to your
+ *    version of the file(s), but you are not obligated to do so. If you do not
+ *    wish to do so, delete this exception statement from your version. If you
+ *    delete this exception statement from all source files in the program,
+ *    then also delete it in the license file.
  */
 
 #pragma once
 
 namespace mongo {
-/**
- * Stub for unit tests to avoid including the server_options library.
- */
+/** Returns true when the running process is `mongos` and false otherwise. */
 bool isMongos();
+
+/** Set the global state flag indicating whether the running process is `mongos` or not. */
+void setMongos(const bool state = true);
 }  // namespace mongo
diff --git a/src/mongo/s/mongos_options.h b/src/mongo/s/mongos_options.h
index 8ac3a1d9321..3e2f5ff4623 100644
--- a/src/mongo/s/mongos_options.h
+++ b/src/mongo/s/mongos_options.h
@@ -31,6 +31,7 @@
 #include "mongo/base/status.h"
 #include "mongo/client/connection_string.h"
 #include "mongo/db/server_options.h"
+#include "mongo/s/is_mongos.h"
 #include "mongo/util/options_parser/environment.h"
 #include "mongo/util/options_parser/option_section.h"
 
@@ -78,8 +79,4 @@ Status validateMongosOptions(const moe::Environment& params);
 Status canonicalizeMongosOptions(moe::Environment* params);
 
 Status storeMongosOptions(const moe::Environment& params);
-
-// This function should eventually go away, but needs to be here now because the sorter and
-// the version manager must know at runtime which binary it is in.
-bool isMongos();
 }
diff --git a/src/mongo/s/s_only.cpp b/src/mongo/s/s_only.cpp
index 2fcfc4c30b2..e012c9045a5 100644
--- a/src/mongo/s/s_only.cpp
+++ b/src/mongo/s/s_only.cpp
@@ -56,10 +56,6 @@ namespace mongo {
 using std::string;
 using std::stringstream;
 
-bool isMongos() {
-    return true;
-}
-
 /**
  * When this callback is run, we record a shard that we've used for useful work in an operation to
  * be read later by getLastError()
diff --git a/src/mongo/s/server.cpp b/src/mongo/s/server.cpp
index 44569f4081a..2bad7e6063f 100644
--- a/src/mongo/s/server.cpp
+++ b/src/mongo/s/server.cpp
@@ -73,6 +73,7 @@
 #include "mongo/s/commands/request.h"
 #include "mongo/s/config.h"
 #include "mongo/s/grid.h"
+#include "mongo/s/is_mongos.h"
 #include "mongo/s/mongos_options.h"
 #include "mongo/s/query/cluster_cursor_cleanup_job.h"
 #include "mongo/s/query/cluster_cursor_manager.h"
@@ -435,6 +436,7 @@ MONGO_INITIALIZER_GENERAL(setSSLManagerType, MONGO_NO_PREREQUISITES, ("SSLManage
 #endif
 
 int mongoSMain(int argc, char* argv[], char** envp) {
+    mongo::setMongos();
     static StaticObserver staticObserver;
     if (argc < 1)
         return EXIT_FAILURE;