1. 22 Mar, 2022 1 commit
    • Meir Shpilraien (Spielrein)'s avatar
      Add new RM_Call flags for script mode, no writes, and error replies. (#10372) · f3855a09
      Meir Shpilraien (Spielrein) authored
      The PR extends RM_Call with 3 new capabilities using new flags that
      are given to RM_Call as part of the `fmt` argument.
      It aims to assist modules that are getting a list of commands to be
      executed from the user (not hard coded as part of the module logic),
      think of a module that implements a new scripting language...
      
      * `S` - Run the command in a script mode, this means that it will raise an
        error if a command which are not allowed inside a script (flaged with the
        `deny-script` flag) is invoked (like SHUTDOWN). In addition, on script mode,
        write commands are not allowed if there is not enough good replicas (as
        configured with `min-replicas-to-write`) and/or a disk error happened.
      
      * `W` - no writes mode, Redis will reject any command that is marked with `write`
        flag. Again can be useful to modules that implement a new scripting language
        and wants to prevent any write commands.
      
      * `E` - Return errors as RedisModuleCallReply. Today the errors that happened
        before the command was invoked (like unknown commands or acl error) return
        a NULL reply and set errno. This might be missing important information about
        the failure and it is also impossible to just pass the error to the user using
        RM_ReplyWithCallReply. This new flag allows you to get a RedisModuleCallReply
        object with the relevant error message and treat it as if it was an error that was
        raised by the command invocation.
      
      Tests were added to verify the new code paths.
      
      In addition small refactoring was done to share some code between modules,
      scripts, and `processCommand` function:
      1. `getAclErrorMessage` was added to `acl.c` to unified to log message extraction
        from the acl result
      2. `checkGoodReplicasStatus` was added to `replication.c` to check the status of
        good replicas. It is used on `scriptVerifyWriteCommandAllow`, `RM_Call`, and
        `processCommand`.
      3. `writeCommandsGetDiskErrorMessage` was added to `server.c` to get the error
        message on persistence failure. Again it is used on `scriptVerifyWriteCommandAllow`,
        `RM_Call`, and `processCommand`.
      f3855a09
  2. 13 Feb, 2022 1 commit
    • Oran Agra's avatar
      Fix and improve module error reply statistics (#10278) · b099889a
      Oran Agra authored
      This PR handles several aspects
      1. Calls to RM_ReplyWithError from thread safe contexts don't violate thread safety.
      2. Errors returning from RM_Call to the module aren't counted in the statistics (they
        might be handled silently by the module)
      3. When a module propagates a reply it got from RM_Call to it's client, then the error
        statistics are counted.
      
      This is done by:
      1. When appending an error reply to the output buffer, we avoid updating the global
        error statistics, instead we cache that error in a deferred list in the client struct.
      2. When creating a RedisModuleCallReply object, the deferred error list is moved from
        the client into that object.
      3. when a module calls RM_ReplyWithCallReply we copy the deferred replies to the dest
        client (if that's a real client, then that's when the error statistics are updated to the server)
      
      Note about RM_ReplyWithCallReply: if the original reply had an array with errors, and the module
      replied with just a portion of the original reply, and not the entire reply, the errors are currently not
      propagated and the errors stats will not get propagated.
      
      Fix #10180
      b099889a
  3. 09 Sep, 2021 1 commit
  4. 04 Aug, 2021 1 commit
    • Meir Shpilraien (Spielrein)'s avatar
      Unified Lua and modules reply parsing and added RESP3 support to RM_Call (#9202) · 2237131e
      Meir Shpilraien (Spielrein) authored
      
      
      ## Current state
      1. Lua has its own parser that handles parsing `reds.call` replies and translates them
        to Lua objects that can be used by the user Lua code. The parser partially handles
        resp3 (missing big number, verbatim, attribute, ...)
      2. Modules have their own parser that handles parsing `RM_Call` replies and translates
        them to RedisModuleCallReply objects. The parser does not support resp3.
      
      In addition, in the future, we want to add Redis Function (#8693) that will probably
      support more languages. At some point maintaining so many parsers will stop
      scaling (bug fixes and protocol changes will need to be applied on all of them).
      We will probably end up with different parsers that support different parts of the
      resp protocol (like we already have today with Lua and modules)
      
      ## PR Changes
      This PR attempt to unified the reply parsing of Lua and modules (and in the future
      Redis Function) by introducing a new parser unit (`resp_parser.c`). The new parser
      handles parsing the reply and calls different callbacks to allow the users (another
      unit that uses the parser, i.e, Lua, modules, or Redis Function) to analyze the reply.
      
      ### Lua API Additions
      The code that handles reply parsing on `scripting.c` was removed. Instead, it uses
      the resp_parser to parse and create a Lua object out of the reply. As mentioned
      above the Lua parser did not handle parsing big numbers, verbatim, and attribute.
      The new parser can handle those and so Lua also gets it for free.
      Those are translated to Lua objects in the following way:
      1. Big Number - Lua table `{'big_number':'<str representation for big number>'}`
      2. Verbatim - Lua table `{'verbatim_string':{'format':'<verbatim format>', 'string':'<verbatim string value>'}}`
      3. Attribute - currently ignored and not expose to the Lua parser, another issue will be open to decide how to expose it.
      
      Tests were added to check resp3 reply parsing on Lua
      
      ### Modules API Additions
      The reply parsing code on `module.c` was also removed and the new resp_parser is used instead.
      In addition, the RedisModuleCallReply was also extracted to a separate unit located on `call_reply.c`
      (in the future, this unit will also be used by Redis Function). A nice side effect of unified parsing is
      that modules now also support resp3. Resp3 can be enabled by giving `3` as a parameter to the
      fmt argument of `RM_Call`. It is also possible to give `0`, which will indicate an auto mode. i.e, Redis
      will automatically chose the reply protocol base on the current client set on the RedisModuleCtx
      (this mode will mostly be used when the module want to pass the reply to the client as is).
      In addition, the following RedisModuleAPI were added to allow analyzing resp3 replies:
      
      * New RedisModuleCallReply types:
         * `REDISMODULE_REPLY_MAP`
         * `REDISMODULE_REPLY_SET`
         * `REDISMODULE_REPLY_BOOL`
         * `REDISMODULE_REPLY_DOUBLE`
         * `REDISMODULE_REPLY_BIG_NUMBER`
         * `REDISMODULE_REPLY_VERBATIM_STRING`
         * `REDISMODULE_REPLY_ATTRIBUTE`
      
      * New RedisModuleAPI:
         * `RedisModule_CallReplyDouble` - getting double value from resp3 double reply
         * `RedisModule_CallReplyBool` - getting boolean value from resp3 boolean reply
         * `RedisModule_CallReplyBigNumber` - getting big number value from resp3 big number reply
         * `RedisModule_CallReplyVerbatim` - getting format and value from resp3 verbatim reply
         * `RedisModule_CallReplySetElement` - getting element from resp3 set reply
         * `RedisModule_CallReplyMapElement` - getting key and value from resp3 map reply
         * `RedisModule_CallReplyAttribute` - getting a reply attribute
         * `RedisModule_CallReplyAttributeElement` - getting key and value from resp3 attribute reply
         
      * New context flags:
         * `REDISMODULE_CTX_FLAGS_RESP3` - indicate that the client is using resp3
      
      Tests were added to check the new RedisModuleAPI
      
      ### Modules API Changes
      * RM_ReplyWithCallReply might return REDISMODULE_ERR if the given CallReply is in resp3
        but the client expects resp2. This is not a breaking change because in order to get a resp3
        CallReply one needs to specifically specify `3` as a parameter to the fmt argument of
        `RM_Call` (as mentioned above).
      
      Tests were added to check this change
      
      ### More small Additions
      * Added `debug set-disable-deny-scripts` that allows to turn on and off the commands no-script
      flag protection. This is used by the Lua resp3 tests so it will be possible to run `debug protocol`
      and check the resp3 parsing code.
      Co-authored-by: default avatarOran Agra <oran@redislabs.com>
      Co-authored-by: default avatarYossi Gottlieb <yossigo@gmail.com>
      2237131e