feat(remote_command): change some remote_command shell output to JSON…

… format (#2058)

Some remote commands shell output are format by json. And some remote
command are not.

Change the output of register_int_command, register_bool_command to
JSON format to improve readability by programs (e.g., Python scripts).

src/nfs/nfs_client_impl.cpp

@@ -26,13 +26,15 @@
 
 #include "nfs_client_impl.h"
 
+#include <cstdint>
 // IWYU pragma: no_include <ext/alloc_traits.h>
 #include <mutex>
 
 #include "absl/strings/string_view.h"
 #include "fmt/core.h"
 #include "nfs/nfs_code_definition.h"
 #include "nfs/nfs_node.h"
+#include "nlohmann/json.hpp"
 #include "runtime/rpc/dns_resolver.h" // IWYU pragma: keep
 #include "runtime/rpc/rpc_host_port.h"
 #include "utils/blob.h"

src/nfs/nfs_server_impl.cpp

@@ -35,6 +35,7 @@
 
 #include "absl/strings/string_view.h"
 #include "nfs/nfs_code_definition.h"
+#include "nlohmann/json.hpp"
 #include "runtime/api_layer1.h"
 #include "runtime/task/async_calls.h"
 #include "utils/TokenBucket.h"

src/utils/command_manager.cpp

@@ -129,27 +129,32 @@ std::string command_manager::set_bool(bool &value,
                                       const std::string &name,
                                       const std::vector<std::string> &args)
 {
+    nlohmann::json msg;
+    msg["error"] = "ok";
     // Query.
     if (args.empty()) {
-        return value ? "true" : "false";
+        msg[name] = value ? "true" : "false";
+        return msg.dump(2);
     }
 
     // Invalid arguments size.
     if (args.size() > 1) {
-        return fmt::format("ERR: invalid arguments, only one boolean argument is acceptable");
+        msg["error"] = "ERR: invalid arguments, only one boolean argument is acceptable";
+        return msg.dump(2);
     }
 
     // Invalid argument.
     bool new_value;
     if (!dsn::buf2bool(args[0], new_value, /* ignore_case */ true)) {
-        return fmt::format("ERR: invalid arguments, '{}' is not a boolean", args[0]);
+        msg["error"] = fmt::format("ERR: invalid arguments, '{}' is not a boolean", args[0]);
+        return msg.dump(2);
     }
 
     // Set to a new value.
     value = new_value;
     LOG_INFO("set {} to {} by remote command", name, new_value);
 
-    return "OK";
+    return msg.dump(2);
 }
 
 command_manager::command_manager()

src/utils/command_manager.h

@@ -32,6 +32,8 @@
 #include <functional>
 #include <map>
 #include <memory>
+#include <nlohmann/json.hpp>
+#include <nlohmann/json_fwd.hpp>
 #include <string>
 #include <vector>
 
@@ -134,34 +136,40 @@ class command_manager : public ::dsn::utils::singleton<command_manager>
                                const std::vector<std::string> &args,
                                const std::function<bool(int64_t value)> &validator)
     {
+        nlohmann::json msg;
+        msg["error"] = "ok";
         // Query.
         if (args.empty()) {
-            return std::to_string(value);
+            msg[name] = fmt::format("{}", std::to_string(value));
+            return msg.dump(2);
         }
 
         // Invalid arguments size.
         if (args.size() > 1) {
-            return fmt::format("ERR: invalid arguments, only one integer argument is acceptable");
+            msg["error"] = "ERR: invalid arguments, only one integer argument is acceptable";
+            return msg.dump(2);
         }
 
         // Reset to the default value.
         if (dsn::utils::iequals(args[0], "DEFAULT")) {
             value = default_value;
-            return "OK";
+            msg[name] = default_value;
+            return msg.dump(2);
         }
 
         // Invalid argument.
         T new_value = 0;
         if (!internal::buf2signed(args[0], new_value) ||
             !validator(static_cast<int64_t>(new_value))) {
-            return {"ERR: invalid arguments"};
+            msg["error"] = "ERR: invalid arguments";
+            return msg.dump(2);
         }
 
         // Set to a new value.
         value = new_value;
         LOG_INFO("set {} to {} by remote command", name, new_value);
 
-        return "OK";
+        return msg.dump(2);
     }
 
     typedef ref_ptr<command_instance> command_instance_ptr;