redict/tests/unit/moduleapi/blockedclient.tcl

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set testmodule [file normalize tests/modules/blockedclient.so]
start_server {tags {"modules"}} {
r module load $testmodule
test {Locked GIL acquisition} {
assert_match "OK" [r acquire_gil]
}
test {Locked GIL acquisition during multi} {
r multi
r acquire_gil
assert_equal {{Blocked client is not supported inside multi}} [r exec]
}
Unified MULTI, LUA, and RM_Call with respect to blocking commands (#8025) Blocking command should not be used with MULTI, LUA, and RM_Call. This is because, the caller, who executes the command in this context, expects a reply. Today, LUA and MULTI have a special (and different) treatment to blocking commands: LUA - Most commands are marked with no-script flag which are checked when executing and command from LUA, commands that are not marked (like XREAD) verify that their blocking mode is not used inside LUA (by checking the CLIENT_LUA client flag). MULTI - Command that is going to block, first verify that the client is not inside multi (by checking the CLIENT_MULTI client flag). If the client is inside multi, they return a result which is a match to the empty key with no timeout (for example blpop inside MULTI will act as lpop) For modules that perform RM_Call with blocking command, the returned results type is REDISMODULE_REPLY_UNKNOWN and the caller can not really know what happened. Disadvantages of the current state are: No unified approach, LUA, MULTI, and RM_Call, each has a different treatment Module can not safely execute blocking command (and get reply or error). Though It is true that modules are not like LUA or MULTI and should be smarter not to execute blocking commands on RM_Call, sometimes you want to execute a command base on client input (for example if you create a module that provides a new scripting language like javascript or python). While modules (on modules command) can check for REDISMODULE_CTX_FLAGS_LUA or REDISMODULE_CTX_FLAGS_MULTI to know not to block the client, there is no way to check if the command came from another module using RM_Call. So there is no way for a module to know not to block another module RM_Call execution. This commit adds a way to unify the treatment for blocking clients by introducing a new CLIENT_DENY_BLOCKING client flag. On LUA, MULTI, and RM_Call the new flag turned on to signify that the client should not be blocked. A blocking command verifies that the flag is turned off before blocking. If a blocking command sees that the CLIENT_DENY_BLOCKING flag is on, it's not blocking and return results which are matches to empty key with no timeout (as MULTI does today). The new flag is checked on the following commands: List blocking commands: BLPOP, BRPOP, BRPOPLPUSH, BLMOVE, Zset blocking commands: BZPOPMIN, BZPOPMAX Stream blocking commands: XREAD, XREADGROUP SUBSCRIBE, PSUBSCRIBE, MONITOR In addition, the new flag is turned on inside the AOF client, we do not want to block the AOF client to prevent deadlocks and commands ordering issues (and there is also an existing assert in the code that verifies it). To keep backward compatibility on LUA, all the no-script flags on existing commands were kept untouched. In addition, a LUA special treatment on XREAD and XREADGROUP was kept. To keep backward compatibility on MULTI (which today allows SUBSCRIBE, and PSUBSCRIBE). We added a special treatment on those commands to allow executing them on MULTI. The only backward compatibility issue that this PR introduces is that now MONITOR is not allowed inside MULTI. Tests were added to verify blocking commands are not blocking the client on LUA, MULTI, or RM_Call. Tests were added to verify the module can check for CLIENT_DENY_BLOCKING flag. Co-authored-by: Oran Agra <oran@redislabs.com> Co-authored-by: Itamar Haber <itamar@redislabs.com>
2020-11-17 11:58:55 -05:00
test {Locked GIL acquisition from RM_Call} {
assert_equal {Blocked client is not allowed} [r do_rm_call acquire_gil]
}
test {Blocking command are not block the client on RM_Call} {
r lpush l test
assert_equal [r do_rm_call blpop l 0] {l test}
r lpush l test
assert_equal [r do_rm_call brpop l 0] {l test}
r lpush l1 test
assert_equal [r do_rm_call brpoplpush l1 l2 0] {test}
assert_equal [r do_rm_call brpop l2 0] {l2 test}
r lpush l1 test
assert_equal [r do_rm_call blmove l1 l2 LEFT LEFT 0] {test}
assert_equal [r do_rm_call brpop l2 0] {l2 test}
r ZADD zset1 0 a 1 b 2 c
assert_equal [r do_rm_call bzpopmin zset1 0] {zset1 a 0}
assert_equal [r do_rm_call bzpopmax zset1 0] {zset1 c 2}
r xgroup create s g $ MKSTREAM
r xadd s * foo bar
assert {[r do_rm_call xread BLOCK 0 STREAMS s 0-0] ne {}}
assert {[r do_rm_call xreadgroup group g c BLOCK 0 STREAMS s >] ne {}}
assert {[r do_rm_call blpop empty_list 0] eq {}}
assert {[r do_rm_call brpop empty_list 0] eq {}}
assert {[r do_rm_call brpoplpush empty_list1 empty_list2 0] eq {}}
assert {[r do_rm_call blmove empty_list1 empty_list2 LEFT LEFT 0] eq {}}
assert {[r do_rm_call bzpopmin empty_zset 0] eq {}}
assert {[r do_rm_call bzpopmax empty_zset 0] eq {}}
r xgroup create empty_stream g $ MKSTREAM
assert {[r do_rm_call xread BLOCK 0 STREAMS empty_stream $] eq {}}
assert {[r do_rm_call xreadgroup group g c BLOCK 0 STREAMS empty_stream >] eq {}}
}
test {Monitor disallow inside RM_Call} {
set e {}
catch {
r do_rm_call monitor
} e
set e
Adds pub/sub channel patterns to ACL (#7993) Fixes #7923. This PR appropriates the special `&` symbol (because `@` and `*` are taken), followed by a literal value or pattern for describing the Pub/Sub patterns that an ACL user can interact with. It is similar to the existing key patterns mechanism in function (additive) and implementation (copy-pasta). It also adds the allchannels and resetchannels ACL keywords, naturally. The default user is given allchannels permissions, whereas new users get whatever is defined by the acl-pubsub-default configuration directive. For backward compatibility in 6.2, the default of this directive is allchannels but this is likely to be changed to resetchannels in the next major version for stronger default security settings. Unless allchannels is set for the user, channel access permissions are checked as follows : * Calls to both PUBLISH and SUBSCRIBE will fail unless a pattern matching the argumentative channel name(s) exists for the user. * Calls to PSUBSCRIBE will fail unless the pattern(s) provided as an argument literally exist(s) in the user's list. Such failures are logged to the ACL log. Runtime changes to channel permissions for a user with existing subscribing clients cause said clients to disconnect unless the new permissions permit the connections to continue. Note, however, that PSUBSCRIBErs' patterns are matched literally, so given the change bar:* -> b*, pattern subscribers to bar:* will be disconnected. Notes/questions: * UNSUBSCRIBE, PUNSUBSCRIBE and PUBSUB remain unprotected due to lack of reasons for touching them.
2020-12-01 07:21:39 -05:00
} {*ERR*DENY BLOCKING*}
Unified MULTI, LUA, and RM_Call with respect to blocking commands (#8025) Blocking command should not be used with MULTI, LUA, and RM_Call. This is because, the caller, who executes the command in this context, expects a reply. Today, LUA and MULTI have a special (and different) treatment to blocking commands: LUA - Most commands are marked with no-script flag which are checked when executing and command from LUA, commands that are not marked (like XREAD) verify that their blocking mode is not used inside LUA (by checking the CLIENT_LUA client flag). MULTI - Command that is going to block, first verify that the client is not inside multi (by checking the CLIENT_MULTI client flag). If the client is inside multi, they return a result which is a match to the empty key with no timeout (for example blpop inside MULTI will act as lpop) For modules that perform RM_Call with blocking command, the returned results type is REDISMODULE_REPLY_UNKNOWN and the caller can not really know what happened. Disadvantages of the current state are: No unified approach, LUA, MULTI, and RM_Call, each has a different treatment Module can not safely execute blocking command (and get reply or error). Though It is true that modules are not like LUA or MULTI and should be smarter not to execute blocking commands on RM_Call, sometimes you want to execute a command base on client input (for example if you create a module that provides a new scripting language like javascript or python). While modules (on modules command) can check for REDISMODULE_CTX_FLAGS_LUA or REDISMODULE_CTX_FLAGS_MULTI to know not to block the client, there is no way to check if the command came from another module using RM_Call. So there is no way for a module to know not to block another module RM_Call execution. This commit adds a way to unify the treatment for blocking clients by introducing a new CLIENT_DENY_BLOCKING client flag. On LUA, MULTI, and RM_Call the new flag turned on to signify that the client should not be blocked. A blocking command verifies that the flag is turned off before blocking. If a blocking command sees that the CLIENT_DENY_BLOCKING flag is on, it's not blocking and return results which are matches to empty key with no timeout (as MULTI does today). The new flag is checked on the following commands: List blocking commands: BLPOP, BRPOP, BRPOPLPUSH, BLMOVE, Zset blocking commands: BZPOPMIN, BZPOPMAX Stream blocking commands: XREAD, XREADGROUP SUBSCRIBE, PSUBSCRIBE, MONITOR In addition, the new flag is turned on inside the AOF client, we do not want to block the AOF client to prevent deadlocks and commands ordering issues (and there is also an existing assert in the code that verifies it). To keep backward compatibility on LUA, all the no-script flags on existing commands were kept untouched. In addition, a LUA special treatment on XREAD and XREADGROUP was kept. To keep backward compatibility on MULTI (which today allows SUBSCRIBE, and PSUBSCRIBE). We added a special treatment on those commands to allow executing them on MULTI. The only backward compatibility issue that this PR introduces is that now MONITOR is not allowed inside MULTI. Tests were added to verify blocking commands are not blocking the client on LUA, MULTI, or RM_Call. Tests were added to verify the module can check for CLIENT_DENY_BLOCKING flag. Co-authored-by: Oran Agra <oran@redislabs.com> Co-authored-by: Itamar Haber <itamar@redislabs.com>
2020-11-17 11:58:55 -05:00
test {subscribe disallow inside RM_Call} {
set e {}
catch {
r do_rm_call subscribe x
} e
set e
Adds pub/sub channel patterns to ACL (#7993) Fixes #7923. This PR appropriates the special `&` symbol (because `@` and `*` are taken), followed by a literal value or pattern for describing the Pub/Sub patterns that an ACL user can interact with. It is similar to the existing key patterns mechanism in function (additive) and implementation (copy-pasta). It also adds the allchannels and resetchannels ACL keywords, naturally. The default user is given allchannels permissions, whereas new users get whatever is defined by the acl-pubsub-default configuration directive. For backward compatibility in 6.2, the default of this directive is allchannels but this is likely to be changed to resetchannels in the next major version for stronger default security settings. Unless allchannels is set for the user, channel access permissions are checked as follows : * Calls to both PUBLISH and SUBSCRIBE will fail unless a pattern matching the argumentative channel name(s) exists for the user. * Calls to PSUBSCRIBE will fail unless the pattern(s) provided as an argument literally exist(s) in the user's list. Such failures are logged to the ACL log. Runtime changes to channel permissions for a user with existing subscribing clients cause said clients to disconnect unless the new permissions permit the connections to continue. Note, however, that PSUBSCRIBErs' patterns are matched literally, so given the change bar:* -> b*, pattern subscribers to bar:* will be disconnected. Notes/questions: * UNSUBSCRIBE, PUNSUBSCRIBE and PUBSUB remain unprotected due to lack of reasons for touching them.
2020-12-01 07:21:39 -05:00
} {*ERR*DENY BLOCKING*}
test {RM_Call from blocked client} {
r hset hash foo bar
r do_bg_rm_call hgetall hash
} {foo bar}
test {RESP version carries through to blocked client} {
for {set client_proto 2} {$client_proto <= 3} {incr client_proto} {
r hello $client_proto
r readraw 1
set ret [r do_fake_bg_true]
if {$client_proto == 2} {
assert_equal $ret {:1}
} else {
assert_equal $ret "#t"
}
r readraw 0
}
}
test {Busy module command} {
set busy_time_limit 50
set old_time_limit [lindex [r config get busy-reply-threshold] 1]
r config set busy-reply-threshold $busy_time_limit
set rd [redis_deferring_client]
# run command that blocks until released
set start [clock clicks -milliseconds]
$rd slow_fg_command 0
$rd flush
# make sure we get BUSY error, and that we didn't get it too early
assert_error {*BUSY Slow module operation*} {r ping}
assert_morethan_equal [expr [clock clicks -milliseconds]-$start] $busy_time_limit
# abort the blocking operation
r stop_slow_fg_command
wait_for_condition 50 100 {
[catch {r ping} e] == 0
} else {
fail "Failed waiting for busy command to end"
}
$rd read
#run command that blocks for 200ms
set start [clock clicks -milliseconds]
$rd slow_fg_command 200000
$rd flush
after 10 ;# try to make sure redis started running the command before we proceed
# make sure we didn't get BUSY error, it simply blocked till the command was done
r ping
assert_morethan_equal [expr [clock clicks -milliseconds]-$start] 200
$rd read
$rd close
r config set busy-reply-threshold $old_time_limit
}
test {RM_Call from blocked client} {
set busy_time_limit 50
set old_time_limit [lindex [r config get busy-reply-threshold] 1]
r config set busy-reply-threshold $busy_time_limit
# trigger slow operation
r set_slow_bg_operation 1
r hset hash foo bar
set rd [redis_deferring_client]
set start [clock clicks -milliseconds]
$rd do_bg_rm_call hgetall hash
# wait till we know we're blocked inside the module
wait_for_condition 50 100 {
[r is_in_slow_bg_operation] eq 1
} else {
fail "Failed waiting for slow operation to start"
}
# make sure we get BUSY error, and that we didn't get here too early
assert_error {*BUSY Slow module operation*} {r ping}
assert_morethan [expr [clock clicks -milliseconds]-$start] $busy_time_limit
# abort the blocking operation
r set_slow_bg_operation 0
wait_for_condition 50 100 {
[r is_in_slow_bg_operation] eq 0
} else {
fail "Failed waiting for slow operation to stop"
}
assert_equal [r ping] {PONG}
r config set busy-reply-threshold $old_time_limit
set res [$rd read]
$rd close
set _ $res
} {foo bar}
test {blocked client reaches client output buffer limit} {
r hset hash big [string repeat x 50000]
r hset hash bada [string repeat x 50000]
r hset hash boom [string repeat x 50000]
r config set client-output-buffer-limit {normal 100000 0 0}
r client setname myclient
catch {r do_bg_rm_call hgetall hash} e
assert_match "*I/O error*" $e
reconnect
set clients [r client list]
assert_no_match "*name=myclient*" $clients
}
test "Unload the module - blockedclient" {
assert_equal {OK} [r module unload blockedclient]
}
}