1. 20 Oct, 2021 1 commit
    • guybe7's avatar
      Treat subcommands as commands (#9504) · 43e736f7
      guybe7 authored
      ## Intro
      
      The purpose is to allow having different flags/ACL categories for
      subcommands (Example: CONFIG GET is ok-loading but CONFIG SET isn't)
      
      We create a small command table for every command that has subcommands
      and each subcommand has its own flags, etc. (same as a "regular" command)
      
      This commit also unites the Redis and the Sentinel command tables
      
      ## Affected commands
      
      CONFIG
      Used to have "admin ok-loading ok-stale no-script"
      Changes:
      1. Dropped "ok-loading" in all except GET (this doesn't change behavior since
      there were checks in the code doing that)
      
      XINFO
      Used to have "read-only random"
      Changes:
      1. Dropped "random" in all except CONSUMERS
      
      XGROUP
      Used to have "write use-memory"
      Changes:
      1. Dropped "use-memory" in all except CREATE and CREATECONSUMER
      
      COMMAND
      No changes.
      
      MEMORY
      Used to have "random read-only"
      Changes:
      1. Dropped "random" in PURGE and USAGE
      
      ACL
      Used to have "admin no-script ok-loading ok-stale"
      Changes:
      1. Dropped "admin" in WHOAMI, GENPASS, and CAT
      
      LATENCY
      No changes.
      
      MODULE
      No changes.
      
      SLOWLOG
      Used to have "admin random ok-loading ok-stale"
      Changes:
      1. Dropped "random" in RESET
      
      OBJECT
      Used to have "read-only random"
      Changes:
      1. Dropped "random" in ENCODING and REFCOUNT
      
      SCRIPT
      Used to have "may-replicate no-script"
      Changes:
      1. Dropped "may-replicate" in all except FLUSH and LOAD
      
      CLIENT
      Used to have "admin no-script random ok-loading ok-stale"
      Changes:
      1. Dropped "random" in all except INFO and LIST
      2. Dropped "admin" in ID, TRACKING, CACHING, GETREDIR, INFO, SETNAME, GETNAME, and REPLY
      
      STRALGO
      No changes.
      
      PUBSUB
      No changes.
      
      CLUSTER
      Changes:
      1. Dropped "admin in countkeysinslots, getkeysinslot, info, nodes, keyslot, myid, and slots
      
      SENTINEL
      No changes.
      
      (note that DEBUG also fits, but we decided not to convert it since it's for
      debugging and anyway undocumented)
      
      ## New sub-command
      This commit adds another element to the per-command output of COMMAND,
      describing the list of subcommands, if any (in the same structure as "regular" commands)
      Also, it adds a new subcommand:
      ```
      COMMAND LIST [FILTERBY (MODULE <module-name>|ACLCAT <cat>|PATTERN <pattern>)]
      ```
      which returns a set of all commands (unless filters), but excluding subcommands.
      
      ## Module API
      A new module API, RM_CreateSubcommand, was added, in order to allow
      module writer to define subcommands
      
      ## ACL changes:
      1. Now, that each subcommand is actually a command, each has its own ACL id.
      2. The old mechanism of allowed_subcommands is redundant
      (blocking/allowing a subcommand is the same as blocking/allowing a regular command),
      but we had to keep it, to support the widespread usage of allowed_subcommands
      to block commands with certain args, that aren't subcommands (e.g. "-select +select|0").
      3. I have renamed allowed_subcommands to allowed_firstargs to emphasize the difference.
      4. Because subcommands are commands in ACL too, you can now use "-" to block subcommands
      (e.g. "+client -client|kill"), which wasn't possible in the past.
      5. It is also possible to use the allowed_firstargs mechanism with subcommand.
      For example: `+config -config|set +config|set|loglevel` will block all CONFIG SET except
      for setting the log level.
      6. All of the ACL changes above required some amount of refactoring.
      
      ## Misc
      1. There are two approaches: Either each subcommand has its own function or all
         subcommands use the same function, determining what to do according to argv[0].
         For now, I took the former approaches only with CONFIG and COMMAND,
         while other commands use the latter approach (for smaller blamelog diff).
      2. Deleted memoryGetKeys: It is no longer needed because MEMORY USAGE now uses the "range" key spec.
      4. Bugfix: GETNAME was missing from CLIENT's help message.
      5. Sentinel and Redis now use the same table, with the same function pointer.
         Some commands have a different implementation in Sentinel, so we redirect
         them (these are ROLE, PUBLISH, and INFO).
      6. Command stats now show the stats per subcommand (e.g. instead of stats just
         for "config" you will have stats for "config|set", "config|get", etc.)
      7. It is now possible to use COMMAND directly on subcommands:
         COMMAND INFO CONFIG|GET (The pipeline syntax was inspired from ACL, and
         can be used in functions lookupCommandBySds and lookupCommandByCString)
      8. STRALGO is now a container command (has "help")
      
      ## Breaking changes:
      1. Command stats now show the stats per subcommand (see (5) above)
      43e736f7