Implement several HELP subcommands

libs/common/RespMemoryWriter.cs

@@ -57,7 +57,7 @@ public void WriteAsciiDirect(ReadOnlySpan<char> span)
         }
 
         /// <summary>
-        /// Writes an array str to memory.
+        /// Writes an array item to memory.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void WriteArrayItem(long item)
@@ -192,7 +192,6 @@ public void WriteEmptyMap()
         /// Write simple error to memory.
         /// </summary>
         /// <param name="errorString">An ASCII encoded error string. The string mustn't contain a CR (\r) or LF (\n) bytes.</param>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void WriteError(scoped ReadOnlySpan<byte> errorString)
         {
             while (!RespWriteUtils.TryWriteError(errorString, ref curr, end))
@@ -227,6 +226,18 @@ public void TryWriteFalse()
             }
         }
 
+        /// <summary>
+        /// Write Help output
+        /// </summary>
+        public void WriteHelp(params string[] Help)
+        {
+            WriteArrayLength(Help.Length);
+            foreach (var help in Help)
+            {
+                WriteSimpleString(help);
+            }
+        }
+
         /// <summary>
         /// Write integer to memory.
         /// </summary>

libs/resources/RespCommandsDocs.json

@@ -68,6 +68,13 @@
           }
         ]
       },
+      {
+        "Command": "ACL_HELP",
+        "Name": "ACL|HELP",
+        "Summary": "Show helpful text about the different subcommands",
+        "Group": "Server",
+        "Complexity": "O(1)"
+      },
       {
         "Command": "ACL_LIST",
         "Name": "ACL|LIST",
@@ -944,6 +951,13 @@
         "Group": "Connection",
         "Complexity": "O(1)"
       },
+      {
+        "Command": "CLIENT_HELP",
+        "Name": "CLIENT|HELP",
+        "Summary": "Show helpful text about the different subcommands",
+        "Group": "Server",
+        "Complexity": "O(1)"
+      },
       {
         "Command": "CLIENT_ID",
         "Name": "CLIENT|ID",
@@ -1722,6 +1736,13 @@
           }
         ]
       },
+      {
+        "Command": "COMMAND_HELP",
+        "Name": "COMMAND|HELP",
+        "Summary": "Show helpful text about the different subcommands",
+        "Group": "Server",
+        "Complexity": "O(1)"
+      },
       {
         "Command": "COMMAND_INFO",
         "Name": "COMMAND|INFO",
@@ -1779,6 +1800,13 @@
           }
         ]
       },
+      {
+        "Command": "CONFIG_HELP",
+        "Name": "CONFIG|HELP",
+        "Summary": "Show helpful text about the different subcommands",
+        "Group": "Server",
+        "Complexity": "O(1)"
+      },
       {
         "Command": "CONFIG_REWRITE",
         "Name": "CONFIG|REWRITE",
@@ -5335,6 +5363,13 @@
     "Group": "Server",
     "Complexity": "Depends on subcommand.",
     "SubCommands": [
+      {
+        "Command": "MEMORY_HELP",
+        "Name": "MEMORY|HELP",
+        "Summary": "Show helpful text about the different subcommands",
+        "Group": "Server",
+        "Complexity": "O(1)"
+      },
       {
         "Command": "MEMORY_USAGE",
         "Name": "MEMORY|USAGE",
@@ -5499,6 +5534,13 @@
     "Group": "Server",
     "Complexity": "Depends on subcommand.",
     "SubCommands": [
+      {
+        "Command": "MODULE_HELP",
+        "Name": "MODULE|HELP",
+        "Summary": "Show helpful text about the different subcommands",
+        "Group": "Server",
+        "Complexity": "O(1)"
+      },
       {
         "Command": "MODULE_LOADCS",
         "Name": "MODULE|LOADCS",
@@ -5931,6 +5973,13 @@
           }
         ]
       },
+      {
+        "Command": "PUBSUB_HELP",
+        "Name": "PUBSUB|HELP",
+        "Summary": "Show helpful text about the different subcommands",
+        "Group": "Server",
+        "Complexity": "O(1)"
+      },
       {
         "Command": "PUBSUB_NUMPAT",
         "Name": "PUBSUB|NUMPAT",
@@ -6590,6 +6639,13 @@
           }
         ]
       },
+      {
+        "Command": "SCRIPT_HELP",
+        "Name": "SCRIPT|HELP",
+        "Summary": "Show helpful text about the different subcommands",
+        "Group": "Server",
+        "Complexity": "O(1)"
+      },
       {
         "Command": "SCRIPT_LOAD",
         "Name": "SCRIPT|LOAD",

libs/resources/RespCommandsInfo.json

@@ -86,6 +86,13 @@
         "Arity": -2,
         "Flags": "Loading, NoScript, Stale",
         "AclCategories": "Slow"
+      },
+      {
+        "Command": "ACL_HELP",
+        "Name": "ACL|HELP",
+        "Arity": 2,
+        "Flags": "Loading, Stale",
+        "AclCategories": "Slow"
       }
     ]
   },
@@ -524,6 +531,13 @@
         "Flags": "Loading, NoScript, Stale",
         "AclCategories": "Connection, Slow"
       },
+      {
+        "Command": "CLIENT_HELP",
+        "Name": "CLIENT|HELP",
+        "Arity": 2,
+        "Flags": "Loading, Stale",
+        "AclCategories": "Slow"
+      },
       {
         "Command": "CLIENT_ID",
         "Name": "CLIENT|ID",
@@ -1018,6 +1032,13 @@
         "Flags": "Loading, Stale",
         "AclCategories": "Connection, Slow"
       },
+      {
+        "Command": "COMMAND_HELP",
+        "Name": "COMMAND|HELP",
+        "Arity": 2,
+        "Flags": "Loading, Stale",
+        "AclCategories": "Slow"
+      },
       {
         "Command": "COMMAND_INFO",
         "Name": "COMMAND|INFO",
@@ -1053,6 +1074,13 @@
         "Flags": "Admin, Loading, NoScript, Stale",
         "AclCategories": "Admin, Dangerous, Slow"
       },
+      {
+        "Command": "CONFIG_HELP",
+        "Name": "CONFIG|HELP",
+        "Arity": 2,
+        "Flags": "Admin, Loading, NoScript, Stale",
+        "AclCategories": "Slow, Garnet"
+      },
       {
         "Command": "CONFIG_REWRITE",
         "Name": "CONFIG|REWRITE",
@@ -2781,8 +2809,8 @@
         "Command": "LATENCY_HELP",
         "Name": "LATENCY|HELP",
         "Arity": 2,
-        "Flags": "Admin, Loading, NoScript, Stale",
-        "AclCategories": "Slow, Garnet"
+        "Flags": "Loading, Stale",
+        "AclCategories": "Slow"
       },
       {
         "Command": "LATENCY_HISTOGRAM",
@@ -3175,6 +3203,13 @@
     "Arity": -2,
     "AclCategories": "Slow",
     "SubCommands": [
+      {
+        "Command": "MEMORY_HELP",
+        "Name": "MEMORY|HELP",
+        "Arity": 2,
+        "Flags": "Loading, Stale",
+        "AclCategories": "Slow"
+      },
       {
         "Command": "MEMORY_USAGE",
         "Name": "MEMORY|USAGE",
@@ -3285,6 +3320,13 @@
         "Arity": -3,
         "Flags": "Admin, NoAsyncLoading, NoScript",
         "AclCategories": "Admin, Dangerous, Slow"
+      },
+      {
+        "Command": "MODULE_HELP",
+        "Name": "MODULE|HELP",
+        "Arity": 2,
+        "Flags": "Loading, Stale",
+        "AclCategories": "Slow"
       }
     ]
   },
@@ -3636,6 +3678,13 @@
         "Flags": "Loading, PubSub, Stale",
         "AclCategories": "PubSub, Slow"
       },
+      {
+        "Command": "PUBSUB_HELP",
+        "Name": "PUBSUB|HELP",
+        "Arity": 2,
+        "Flags": "Loading, Stale",
+        "AclCategories": "Slow"
+      },
       {
         "Command": "PUBSUB_NUMPAT",
         "Name": "PUBSUB|NUMPAT",
@@ -4035,6 +4084,13 @@
           "response_policy:all_succeeded"
         ]
       },
+      {
+        "Command": "SCRIPT_HELP",
+        "Name": "SCRIPT|HELP",
+        "Arity": 2,
+        "Flags": "Loading, Stale",
+        "AclCategories": "Slow"
+      },
       {
         "Command": "SCRIPT_LOAD",
         "Name": "SCRIPT|LOAD",

libs/server/Lua/LuaCommands.cs

@@ -271,6 +271,34 @@ private bool NetworkScriptFlush()
             return true;
         }
 
+
+        /// <summary>
+        /// SCRIPT HELP
+        /// </summary>
+        /// <returns></returns>
+        private bool NetworkScriptHelp()
+        {
+            if (parseState.Count != 0)
+            {
+                return AbortWithWrongNumberOfArguments("script|help");
+            }
+
+            WriteHelp(
+                "SCRIPT <subcommand> [<arg> [value] [opt] ...]. Subcommands are:",
+                "EXISTS <sha1> [<sha1> ...]",
+                "\tReturn information about the existence of the scripts in the script cache.",
+                "FLUSH [ASYNC|SYNC]",
+                "\tFlush the Lua scripts cache. Very dangerous on replicas. Valid modes are:",
+                "\t* ASYNC: Asynchronously flush the scripts cache.",
+                "\t* SYNC: Synchronously flush the scripts cache.",
+                "LOAD <script>",
+                "\tLoad a script into the scripts cache without executing it.",
+                "HELP",
+                "\tPrint this help.");
+
+            return true;
+        }
+
         /// <summary>
         /// SCRIPT|LOAD
         /// </summary>

libs/server/Metrics/Latency/RespLatencyCommands.cs

@@ -17,18 +17,11 @@ private bool NetworkLatencyHelp()
             // No additional arguments
             if (parseState.Count != 0)
             {
-                return AbortWithErrorMessage($"ERR Unknown subcommand or wrong number of arguments for LATENCY HELP.");
+                return AbortWithWrongNumberOfArguments("latency|help");
             }
 
-            List<string> latencyCommands = RespLatencyHelp.GetLatencyCommands();
-            while (!RespWriteUtils.TryWriteArrayLength(latencyCommands.Count, ref dcurr, dend))
-                SendAndReset();
-
-            foreach (string command in latencyCommands)
-            {
-                while (!RespWriteUtils.TryWriteSimpleString(command, ref dcurr, dend))
-                    SendAndReset();
-            }
+            var latencyCommands = RespLatencyHelp.GetLatencyCommands();
+            WriteHelp(latencyCommands);
 
             return true;
         }

libs/server/Metrics/Latency/RespLatencyHelp.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
-using System.Collections.Generic;
-
 namespace Garnet.server
 {
     /// <summary>
@@ -14,10 +12,10 @@ static class RespLatencyHelp
         /// Get supported latency commands and a short description
         /// </summary>
         /// <returns></returns>
-        public static List<string> GetLatencyCommands()
+        public static string[] GetLatencyCommands()
         {
-            return new List<string>()
-            {
+            return
+            [
                 "LATENCY <subcommand> [<arg> [value] [opt] ...]. Subcommands are:",
                 "HISTOGRAM [EVENT [EVENT...]]",
                 "\tReturn latency histogram of one or more <event> classes.",
@@ -27,7 +25,7 @@ public static List<string> GetLatencyCommands()
                 "\t(default: reset all data for all event classes).",
                 "HELP",
                 "\tPrints this help"
-            };
+            ];
         }
     }
 }

libs/server/Metrics/Slowlog/RespSlowlogCommands.cs

@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using Garnet.common;
@@ -23,15 +22,8 @@ private bool NetworkSlowLogHelp()
                 return AbortWithWrongNumberOfArguments(nameof(RespCommand.SLOWLOG_HELP));
             }
 
-            List<string> slowLogCommands = RespSlowLogHelp.GetSlowLogCommands();
-            while (!RespWriteUtils.TryWriteArrayLength(slowLogCommands.Count, ref dcurr, dend))
-                SendAndReset();
-
-            foreach (string command in slowLogCommands)
-            {
-                while (!RespWriteUtils.TryWriteSimpleString(command, ref dcurr, dend))
-                    SendAndReset();
-            }
+            var slowLogCommands = RespSlowLogHelp.GetSlowLogCommands();
+            WriteHelp(slowLogCommands);
 
             return true;
         }