[sonic-db-cli] Support --json option

common/redisreply.cpp

@@ -6,6 +6,7 @@
 #include <sstream>
 #include <functional>
 #include <boost/algorithm/string.hpp>
+#include <nlohmann/json.hpp>
 
 #include "common/logger.h"
 #include "common/redisreply.h"
@@ -291,6 +292,80 @@ string RedisReply::to_string(redisReply *reply, string command)
     }
 }
 
+static nlohmann::ordered_json buildJsonDict(struct redisReply **element, size_t elements)
+{
+    if (elements%2 != 0)
+    {
+        throw system_error(make_error_code(errc::io_error),
+                           "Invalid result");
+    }
+
+    auto result = nlohmann::ordered_json::object();
+    for (unsigned int i = 0; i < elements; i += 2)
+    {
+        result[RedisReply::to_string(element[i])] = RedisReply::to_string(element[i + 1]);
+    }
+
+    return result;
+}
+
+static nlohmann::ordered_json buildJsonReply(redisReply *reply, const string& command)
+{
+    switch(reply->type)
+    {
+    case REDIS_REPLY_INTEGER:
+        return reply->integer;
+
+    case REDIS_REPLY_NIL:
+        return nullptr;
+
+    case REDIS_REPLY_STRING:
+    case REDIS_REPLY_ERROR:
+    case REDIS_REPLY_STATUS:
+        return string(reply->str, reply->len);
+
+    case REDIS_REPLY_ARRAY:
+    {
+        if (command == "HGETALL")
+        {
+            return buildJsonDict(reply->element, reply->elements);
+        }
+
+        if (command == "HSCAN" && reply->elements == 2)
+        {
+            auto result = nlohmann::ordered_json::array();
+            result.push_back(buildJsonReply(reply->element[0], string()));
+            result.push_back(buildJsonDict(reply->element[1]->element, reply->element[1]->elements));
+            return result;
+        }
+
+        auto result = nlohmann::ordered_json::array();
+        for (unsigned int i = 0; i < reply->elements; i++)
+        {
+            result.push_back(buildJsonReply(reply->element[i], string()));
+        }
+        return result;
+    }
+
+    default:
+        SWSS_LOG_ERROR("invalid type %d for message", reply->type);
+        return nullptr;
+    }
+}
+
+string RedisReply::to_json_string(redisReply *reply, string command)
+{
+    /*
+        JSON output mode for sonic-db-cli --json.
+        Unlike to_string(), this does not emulate redis-py output: replies map
+        directly to JSON types (integer -> number, nil -> null, status/error -> string),
+        except that HGETALL (and the field map element of HSCAN) become a JSON object.
+        Bytes that are not valid UTF-8 are replaced with U+FFFD rather than failing.
+    */
+    auto result = buildJsonReply(reply, command);
+    return result.dump(-1, ' ', false, nlohmann::ordered_json::error_handler_t::replace);
+}
+
 string RedisReply::formatReply(string command, long long integer)
 {
     if (g_intToBoolCommands.find(command) != g_intToBoolCommands.end())

common/redisreply.h

@@ -98,6 +98,8 @@ class RedisReply
 
     static std::string to_string(redisReply *reply, std::string command = std::string());
 
+    static std::string to_json_string(redisReply *reply, std::string command = std::string());
+
 private:
     void checkStatus(const char *status);
     void checkReply();

sonic-db-cli/sonic-db-cli.cpp

@@ -12,7 +12,7 @@ using namespace std;
 
 void printUsage()
 {
-    cout << "usage: sonic-db-cli [-h] [-s] [-n NAMESPACE] db_or_op [cmd [cmd ...]]" << endl;
+    cout << "usage: sonic-db-cli [-h] [-s] [-j] [-n NAMESPACE] db_or_op [cmd [cmd ...]]" << endl;
     cout << endl;
     cout << "SONiC DB CLI:" << endl;
     cout << endl;
@@ -23,6 +23,7 @@ void printUsage()
     cout << "optional arguments:" << endl;
     cout << "  -h, --help            show this help message and exit" << endl;
     cout << "  -s, --unixsocket      Override use of tcp_port and use unixsocket" << endl;
+    cout << "  -j, --json            Print command result as JSON" << endl;
     cout << "  -n NAMESPACE, --namespace NAMESPACE" << endl;
     cout << "                        Namespace string to use asic0/asic1.../asicn" << endl;
     cout << endl;
@@ -133,7 +134,8 @@ int executeCommands(
     const string& db_name,
     vector<string>& commands,
     const string& netns,
-    bool useUnixSocket)
+    bool useUnixSocket,
+    bool useJson)
 {
     shared_ptr<DBConnector> client = nullptr;
     try
@@ -169,7 +171,14 @@ int executeCommands(
         with these changes, it is enough for us to mimic redis-cli in SONiC so far since no application uses tty mode redis-cli output
         */
         auto commandName = getCommandName(commands);
-        cout << RedisReply::to_string(reply.getContext(), commandName) << endl;
+        if (useJson)
+        {
+            cout << RedisReply::to_json_string(reply.getContext(), commandName) << endl;
+        }
+        else
+        {
+            cout << RedisReply::to_string(reply.getContext(), commandName) << endl;
+        }
     }
     catch (const std::system_error& e)
     {
@@ -186,10 +195,11 @@ void parseCliArguments(
     Options &options)
 {
     // Parse argument with getopt https://man7.org/linux/man-pages/man3/getopt.3.html
-    const char* short_options = "hsn";
+    const char* short_options = "hsjn";
     static struct option long_options[] = {
        {"help",        optional_argument, NULL,  'h' },
        {"unixsocket",  optional_argument, NULL,  's' },
+       {"json",        no_argument,       NULL,  'j' },
        {"namespace",   optional_argument, NULL,  'n' },
        // The last element of the array has to be filled with zeros.
        {0,          0,       0,  0 }
@@ -211,6 +221,10 @@ void parseCliArguments(
                     options.m_unixsocket = true;
                     break;
 
+                case 'j':
+                    options.m_json = true;
+                    break;
+
                 case 'n':
                     if (optind < argc)
                     {
@@ -298,7 +312,7 @@ int sonic_db_cli(
                 initializeConfig();
             }
 
-            return executeCommands(dbOrOperation, commands, netns, useUnixSocket);
+            return executeCommands(dbOrOperation, commands, netns, useUnixSocket, options.m_json);
         }
         else if (dbOrOperation == "PING"
                 || dbOrOperation == "SAVE"

sonic-db-cli/sonic-db-cli.h

@@ -12,6 +12,7 @@ struct Options
 {
     bool m_help = false;
     bool m_unixsocket = false;
+    bool m_json = false;
     std::string m_namespace;
     std::string m_db_or_op;
     std::vector<std::string> m_cmd;
@@ -30,7 +31,8 @@ int executeCommands(
     const std::string& db_name,
     std::vector<std::string>& commands,
     const std::string& netns,
-    bool isTcpConn);
+    bool isTcpConn,
+    bool useJson = false);
 
 std::string handleSingleOperation(
     const std::string& netns,

tests/cli_test_data/cli_help_output.txt

@@ -1,4 +1,4 @@
-usage: sonic-db-cli [-h] [-s] [-n NAMESPACE] db_or_op [cmd [cmd ...]]
+usage: sonic-db-cli [-h] [-s] [-j] [-n NAMESPACE] db_or_op [cmd [cmd ...]]
 
 SONiC DB CLI:
 
@@ -9,6 +9,7 @@ positional arguments:
 optional arguments:
   -h, --help            show this help message and exit
   -s, --unixsocket      Override use of tcp_port and use unixsocket
+  -j, --json            Print command result as JSON
   -n NAMESPACE, --namespace NAMESPACE
                         Namespace string to use asic0/asic1.../asicn
 

tests/cli_ut.cpp

@@ -147,6 +147,83 @@ TEST(sonic_db_cli, test_cli_hscan_commands)
     EXPECT_EQ("{'testfield': \"{'value': 'with qute'}\"}\n", output);
 }
 
+TEST(sonic_db_cli, test_cli_json_output)
+{
+    char *args[7];
+    args[0] = "sonic-db-cli";
+    args[1] = "-j";
+    args[2] = "TEST_DB";
+
+    // clear database, status reply becomes a JSON string
+    args[3] = "FLUSHDB";
+    auto output = runCli(4, args);
+    EXPECT_EQ("\"OK\"\n", output);
+
+    // hset to test DB, integer reply becomes a JSON number
+    args[3] = "HSET";
+    args[4] = "testkey";
+    args[5] = "testfield";
+    args[6] = "testvalue";
+    output = runCli(7, args);
+    EXPECT_EQ("1\n", output);
+
+    // hgetall from test db becomes a JSON object
+    args[3] = "HGETALL";
+    args[4] = "testkey";
+    output = runCli(5, args);
+    EXPECT_EQ("{\"testfield\":\"testvalue\"}\n", output);
+
+    // hgetall of a missing key becomes an empty JSON object
+    args[3] = "HGETALL";
+    args[4] = "notexistkey";
+    output = runCli(5, args);
+    EXPECT_EQ("{}\n", output);
+
+    // hscan from test db, cursor is a JSON string and fields a JSON object
+    args[3] = "HSCAN";
+    args[4] = "testkey";
+    args[5] = "0";
+    output = runCli(6, args);
+    EXPECT_EQ("[\"0\",{\"testfield\":\"testvalue\"}]\n", output);
+
+    // values with quote characters are escaped
+    args[3] = "HSET";
+    args[4] = "quotekey";
+    args[5] = "testfield";
+    args[6] = "va'l\"ue";
+    output = runCli(7, args);
+    EXPECT_EQ("1\n", output);
+
+    args[3] = "HGETALL";
+    args[4] = "quotekey";
+    output = runCli(5, args);
+    EXPECT_EQ("{\"testfield\":\"va'l\\\"ue\"}\n", output);
+
+    // get from test db becomes a quoted JSON string
+    args[3] = "GET";
+    args[4] = "notexistkey";
+    output = runCli(5, args);
+    EXPECT_EQ("null\n", output);
+
+    // keys from test db becomes a JSON array
+    args[3] = "DEL";
+    args[4] = "quotekey";
+    output = runCli(5, args);
+    EXPECT_EQ("1\n", output);
+
+    args[3] = "keys";
+    args[4] = "*";
+    output = runCli(5, args);
+    EXPECT_EQ("[\"testkey\"]\n", output);
+
+    // long option works as well
+    args[1] = "--json";
+    args[3] = "HGETALL";
+    args[4] = "testkey";
+    output = runCli(5, args);
+    EXPECT_EQ("{\"testfield\":\"testvalue\"}\n", output);
+}
+
 TEST(sonic_db_cli, test_cli_pop_commands)
 {
     char *args[10];