The problem is that WAITAOF could have hang in case commands were
propagated only to replicas.
This can happen if a module uses RM_Call with the REDISMODULE_ARGV_NO_AOF flag.
In that case, master_repl_offset would increase, but there would be nothing to fsync, so
in the absence of other traffic, fsynced_reploff_pending would stay the static, and WAITAOF can hang.
This commit updates fsynced_reploff_pending to the latest offset in flushAppendOnlyFile in case
there's nothing to fsync. i.e. in case it's behind because of the above mentions case it'll be refreshed
and release the WAITAOF.
Other changes:
Fix a race in wait.tcl (client getting blocked vs. the fsync thread)
* Make it clear that current_client is the root client that was called by
external connection
* add executing_client which is the client that runs the current command
(can be a module or a script)
* Remove script_caller that was used for commands that have CLIENT_SCRIPT
to get the client that called the script. in most cases, that's the current_client,
and in others (when being called from a module), it could be an intermediate
client when we actually want the original one used by the external connection.
bugfixes:
* RM_Call with C flag should log ACL errors with the requested user rather than
the one used by the original client, this also solves a crash when RM_Call is used
with C flag from a detached thread safe context.
* addACLLogEntry would have logged info about the script_caller, but in case the
script was issued by a module command we actually want the current_client. the
exception is when RM_Call is called from a timer event, in which case we don't
have a current_client.
behavior changes:
* client side tracking for scripts now tracks the keys that are read by the script
instead of the keys that are declared by the caller for EVAL
other changes:
* Log both current_client and executing_client in the crash log.
* remove prepareLuaClient and resetLuaClient, being dead code that was forgotten.
* remove scriptTimeSnapshot and snapshot_time and instead add cmd_time_snapshot
that serves all commands and is reset only when execution nesting starts.
* remove code to propagate CLIENT_FORCE_REPL from the executed command
to the script caller since scripts aren't propagated anyway these days and anyway
this flag wouldn't have had an effect since CLIENT_PREVENT_PROP is added by scriptResetRun.
* fix a module GIL violation issue in afterSleep that was introduced in #10300 (unreleased)
Motivation: for applications that use RM ACL verification functions, they would
want to return errors back to the user, in ways that are consistent with Redis.
While investigating how we should return ACL errors to the user, we realized that
Redis isn't consistent, and currently returns ACL error strings in 3 primary ways.
[For the actual implications of this change, see the "Impact" section at the bottom]
1. how it returns an error when calling a command normally
ACL_DENIED_CMD -> "this user has no permissions to run the '%s' command"
ACL_DENIED_KEY -> "this user has no permissions to access one of the keys used as arguments"
ACL_DENIED_CHANNEL -> "this user has no permissions to access one of the channels used as arguments"
2. how it returns an error when calling via 'acl dryrun' command
ACL_DENIED_CMD -> "This user has no permissions to run the '%s' command"
ACL_DENIED_KEY -> "This user has no permissions to access the '%s' key"
ACL_DENIED_CHANNEL -> "This user has no permissions to access the '%s' channel"
3. how it returns an error via RM_Call (and scripting is similar).
ACL_DENIED_CMD -> "can't run this command or subcommand";
ACL_DENIED_KEY -> "can't access at least one of the keys mentioned in the command arguments";
ACL_DENIED_CHANNEL -> "can't publish to the channel mentioned in the command";
In addition, if one wants to use RM_Call's "dry run" capability instead of the RM ACL
functions directly, one also sees a different problem than it returns ACL errors with a -ERR,
not a -PERM, so it can't be returned directly to the caller.
This PR modifies the code to generate a base message in a common manner with the ability
to set verbose flag for acl dry run errors, and keep it unset for normal/rm_call/script cases
```c
sds getAclErrorMessage(int acl_res, user *user, struct redisCommand *cmd, sds errored_val, int verbose) {
switch (acl_res) {
case ACL_DENIED_CMD:
return sdscatfmt(sdsempty(), "User %S has no permissions to run "
"the '%S' command", user->name, cmd->fullname);
case ACL_DENIED_KEY:
if (verbose) {
return sdscatfmt(sdsempty(), "User %S has no permissions to access "
"the '%S' key", user->name, errored_val);
} else {
return sdsnew("No permissions to access a key");
}
case ACL_DENIED_CHANNEL:
if (verbose) {
return sdscatfmt(sdsempty(), "User %S has no permissions to access "
"the '%S' channel", user->name, errored_val);
} else {
return sdsnew("No permissions to access a channel");
}
}
```
The caller can append/prepend the message (adding NOPERM for normal/RM_Call or indicating it's within a script).
Impact:
- Plain commands, as well as scripts and RM_Call now include the user name.
- ACL DRYRUN remains the only one that's verbose (mentions the offending channel or key name)
- Changes RM_Call ACL errors from being a `-ERR` to being `-NOPERM` (besides for textual changes)
**This somewhat a breaking change, but it only affects the RM_Call with both `C` and `E`, or `D`**
- Changes ACL errors in scripts textually from being
`The user executing the script <old non unified text>`
to
`ACL failure in script: <new unified text>`
Adds a number of user management/ACL validaiton/command execution functions to improve a
Redis module's ability to enforce ACLs correctly and easily.
* RM_SetContextUser - sets a RedisModuleUser on the context, which RM_Call will use to both
validate ACLs (if requested and set) as well as assign to the client so that scripts executed via
RM_Call will have proper ACL validation.
* RM_SetModuleUserACLString - Enables one to pass an entire ACL string, not just a single OP
and have it applied to the user
* RM_GetModuleUserACLString - returns a stringified version of the user's ACL (same format as dump
and list). Contains an optimization to cache the stringified version until the underlying ACL is modified.
* Slightly re-purpose the "C" flag to RM_Call from just being about ACL check before calling the
command, to actually running the command with the right user, so that it also affects commands
inside EVAL scripts. see #11231
