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Merge pull request #6235 from oranagra/module_rdb_load_errors

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Allow modules to handle RDB loading errors.
This commit is contained in:
Salvatore Sanfilippo 2019-09-26 11:52:42 +02:00 committed by GitHub
commit 959fb5cf68
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6 changed files with 147 additions and 9 deletions
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64
src/module.c
View File

@ -52,6 +52,7 @@ struct RedisModule {
list *using; /* List of modules we use some APIs of. */
list *filters; /* List of filters the module has registered. */
int in_call; /* RM_Call() nesting level */
int options; /* Moduile options and capabilities. */
};
typedef struct RedisModule RedisModule;
@ -772,6 +773,19 @@ long long RM_Milliseconds(void) {
return mstime();
}
/* Set flags defining capabilities or behavior bit flags.
*
* REDISMODULE_OPTIONS_HANDLE_IO_ERRORS:
* Generally, modules don't need to bother with this, as the process will just
* terminate if a read error happens, however, setting this flag would allow
* repl-diskless-load to work if enabled.
* The module should use RedisModule_IsIOError after reads, before using the
* data that was read, and in case of error, propagate it upwards, and also be
* able to release the partially populated value and all it's allocations. */
void RM_SetModuleOptions(RedisModuleCtx *ctx, int options) {
ctx->module->options = options;
}
/* --------------------------------------------------------------------------
* Automatic memory management for modules
* -------------------------------------------------------------------------- */
@ -3150,9 +3164,14 @@ void *RM_ModuleTypeGetValue(RedisModuleKey *key) {
* RDB loading and saving functions
* -------------------------------------------------------------------------- */
/* Called when there is a load error in the context of a module. This cannot
* be recovered like for the built-in types. */
/* Called when there is a load error in the context of a module. On some
* modules this cannot be recovered, but if the module declared capability
* to handle errors, we'll raise a flag rather than exiting. */
void moduleRDBLoadError(RedisModuleIO *io) {
if (io->ctx->module->options & REDISMODULE_OPTIONS_HANDLE_IO_ERRORS) {
io->error = 1;
return;
}
serverLog(LL_WARNING,
"Error loading data from RDB (short read or EOF). "
"Read performed by module '%s' about type '%s' "
@ -3163,6 +3182,33 @@ void moduleRDBLoadError(RedisModuleIO *io) {
exit(1);
}
/* Returns 0 if there's at least one registered data type that did not declare
* REDISMODULE_OPTIONS_HANDLE_IO_ERRORS, in which case diskless loading should
* be avoided since it could cause data loss. */
int moduleAllDatatypesHandleErrors() {
dictIterator *di = dictGetIterator(modules);
dictEntry *de;
while ((de = dictNext(di)) != NULL) {
struct RedisModule *module = dictGetVal(de);
if (listLength(module->types) &&
!(module->options & REDISMODULE_OPTIONS_HANDLE_IO_ERRORS))
{
dictReleaseIterator(di);
return 0;
}
}
dictReleaseIterator(di);
return 1;
}
/* Returns true if any previous IO API failed.
* for Load* APIs the REDISMODULE_OPTIONS_HANDLE_IO_ERRORS flag must be set with
* RediModule_SetModuleOptions first. */
int RM_IsIOError(RedisModuleIO *io) {
return io->error;
}
/* Save an unsigned 64 bit value into the RDB file. This function should only
* be called in the context of the rdb_save method of modules implementing new
* data types. */
@ -3186,6 +3232,7 @@ saveerr:
* be called in the context of the rdb_load method of modules implementing
* new data types. */
uint64_t RM_LoadUnsigned(RedisModuleIO *io) {
if (io->error) return 0;
if (io->ver == 2) {
uint64_t opcode = rdbLoadLen(io->rio,NULL);
if (opcode != RDB_MODULE_OPCODE_UINT) goto loaderr;
@ -3197,7 +3244,7 @@ uint64_t RM_LoadUnsigned(RedisModuleIO *io) {
loaderr:
moduleRDBLoadError(io);
return 0; /* Never reached. */
return 0;
}
/* Like RedisModule_SaveUnsigned() but for signed 64 bit values. */
@ -3256,6 +3303,7 @@ saveerr:
/* Implements RM_LoadString() and RM_LoadStringBuffer() */
void *moduleLoadString(RedisModuleIO *io, int plain, size_t *lenptr) {
if (io->error) return NULL;
if (io->ver == 2) {
uint64_t opcode = rdbLoadLen(io->rio,NULL);
if (opcode != RDB_MODULE_OPCODE_STRING) goto loaderr;
@ -3267,7 +3315,7 @@ void *moduleLoadString(RedisModuleIO *io, int plain, size_t *lenptr) {
loaderr:
moduleRDBLoadError(io);
return NULL; /* Never reached. */
return NULL;
}
/* In the context of the rdb_load method of a module data type, loads a string
@ -3316,6 +3364,7 @@ saveerr:
/* In the context of the rdb_save method of a module data type, loads back the
* double value saved by RedisModule_SaveDouble(). */
double RM_LoadDouble(RedisModuleIO *io) {
if (io->error) return 0;
if (io->ver == 2) {
uint64_t opcode = rdbLoadLen(io->rio,NULL);
if (opcode != RDB_MODULE_OPCODE_DOUBLE) goto loaderr;
@ -3327,7 +3376,7 @@ double RM_LoadDouble(RedisModuleIO *io) {
loaderr:
moduleRDBLoadError(io);
return 0; /* Never reached. */
return 0;
}
/* In the context of the rdb_save method of a module data type, saves a float
@ -3352,6 +3401,7 @@ saveerr:
/* In the context of the rdb_save method of a module data type, loads back the
* float value saved by RedisModule_SaveFloat(). */
float RM_LoadFloat(RedisModuleIO *io) {
if (io->error) return 0;
if (io->ver == 2) {
uint64_t opcode = rdbLoadLen(io->rio,NULL);
if (opcode != RDB_MODULE_OPCODE_FLOAT) goto loaderr;
@ -3363,7 +3413,7 @@ float RM_LoadFloat(RedisModuleIO *io) {
loaderr:
moduleRDBLoadError(io);
return 0; /* Never reached. */
return 0;
}
/* Iterate over modules, and trigger rdb aux saving for the ones modules types
@ -5461,6 +5511,8 @@ void moduleRegisterCoreAPI(void) {
REGISTER_API(ModuleTypeSetValue);
REGISTER_API(ModuleTypeGetType);
REGISTER_API(ModuleTypeGetValue);
REGISTER_API(IsIOError);
REGISTER_API(SetModuleOptions);
REGISTER_API(SaveUnsigned);
REGISTER_API(LoadUnsigned);
REGISTER_API(SaveSigned);

7
src/redismodule.h
View File

@ -144,6 +144,9 @@ typedef uint64_t RedisModuleTimerID;
/* Do filter RedisModule_Call() commands initiated by module itself. */
#define REDISMODULE_CMDFILTER_NOSELF (1<<0)
/* Declare that the module can handle errors with RedisModule_SetModuleOptions. */
#define REDISMODULE_OPTIONS_HANDLE_IO_ERRORS (1<<0)
/* ------------------------- End of common defines ------------------------ */
#ifndef REDISMODULE_CORE
@ -280,6 +283,8 @@ RedisModuleType *REDISMODULE_API_FUNC(RedisModule_CreateDataType)(RedisModuleCtx
int REDISMODULE_API_FUNC(RedisModule_ModuleTypeSetValue)(RedisModuleKey *key, RedisModuleType *mt, void *value);
RedisModuleType *REDISMODULE_API_FUNC(RedisModule_ModuleTypeGetType)(RedisModuleKey *key);
void *REDISMODULE_API_FUNC(RedisModule_ModuleTypeGetValue)(RedisModuleKey *key);
int REDISMODULE_API_FUNC(RedisModule_IsIOError)(RedisModuleIO *io);
void REDISMODULE_API_FUNC(RedisModule_SetModuleOptions)(RedisModuleCtx *ctx, int options);
void REDISMODULE_API_FUNC(RedisModule_SaveUnsigned)(RedisModuleIO *io, uint64_t value);
uint64_t REDISMODULE_API_FUNC(RedisModule_LoadUnsigned)(RedisModuleIO *io);
void REDISMODULE_API_FUNC(RedisModule_SaveSigned)(RedisModuleIO *io, int64_t value);
@ -454,6 +459,8 @@ static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int
REDISMODULE_GET_API(ModuleTypeSetValue);
REDISMODULE_GET_API(ModuleTypeGetType);
REDISMODULE_GET_API(ModuleTypeGetValue);
REDISMODULE_GET_API(IsIOError);
REDISMODULE_GET_API(SetModuleOptions);
REDISMODULE_GET_API(SaveUnsigned);
REDISMODULE_GET_API(LoadUnsigned);
REDISMODULE_GET_API(SaveSigned);

9
src/replication.c
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@ -1139,8 +1139,15 @@ void restartAOFAfterSYNC() {
static int useDisklessLoad() {
/* compute boolean decision to use diskless load */
return server.repl_diskless_load == REPL_DISKLESS_LOAD_SWAPDB ||
int enabled = server.repl_diskless_load == REPL_DISKLESS_LOAD_SWAPDB ||
(server.repl_diskless_load == REPL_DISKLESS_LOAD_WHEN_DB_EMPTY && dbTotalServerKeyCount()==0);
/* Check all modules handle read errors, otherwise it's not safe to use diskless load. */
if (enabled && !moduleAllDatatypesHandleErrors()) {
serverLog(LL_WARNING,
"Skipping diskless-load because there are modules that don't handle read errors.");
enabled = 0;
}
return enabled;
}
/* Helper function for readSyncBulkPayload() to make backups of the current

1
src/server.h
View File

@ -1541,6 +1541,7 @@ void moduleReleaseGIL(void);
void moduleNotifyKeyspaceEvent(int type, const char *event, robj *key, int dbid);
void moduleCallCommandFilters(client *c);
ssize_t rdbSaveModulesAux(rio *rdb, int when);
int moduleAllDatatypesHandleErrors();
/* Utils */
long long ustime(void);

13
tests/modules/testrdb.c
View File

@ -15,6 +15,8 @@ RedisModuleString *after_str = NULL;
void *testrdb_type_load(RedisModuleIO *rdb, int encver) {
int count = RedisModule_LoadSigned(rdb);
if (RedisModule_IsIOError(rdb))
return NULL;
assert(count==1);
assert(encver==1);
RedisModuleString *str = RedisModule_LoadString(rdb);
@ -57,6 +59,8 @@ int testrdb_aux_load(RedisModuleIO *rdb, int encver, int when) {
RedisModule_FreeString(ctx, before_str);
before_str = NULL;
int count = RedisModule_LoadSigned(rdb);
if (RedisModule_IsIOError(rdb))
return REDISMODULE_ERR;
if (count)
before_str = RedisModule_LoadString(rdb);
} else {
@ -64,14 +68,19 @@ int testrdb_aux_load(RedisModuleIO *rdb, int encver, int when) {
RedisModule_FreeString(ctx, after_str);
after_str = NULL;
int count = RedisModule_LoadSigned(rdb);
if (RedisModule_IsIOError(rdb))
return REDISMODULE_ERR;
if (count)
after_str = RedisModule_LoadString(rdb);
}
if (RedisModule_IsIOError(rdb))
return REDISMODULE_ERR;
return REDISMODULE_OK;
}
void testrdb_type_free(void *value) {
RedisModule_FreeString(NULL, (RedisModuleString*)value);
if (value)
RedisModule_FreeString(NULL, (RedisModuleString*)value);
}
int testrdb_set_before(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
@ -171,6 +180,8 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
if (RedisModule_Init(ctx,"testrdb",1,REDISMODULE_APIVER_1) == REDISMODULE_ERR)
return REDISMODULE_ERR;
RedisModule_SetModuleOptions(ctx, REDISMODULE_OPTIONS_HANDLE_IO_ERRORS);
if (argc > 0)
RedisModule_StringToLongLong(argv[0], &conf_aux_count);

62
tests/unit/moduleapi/testrdb.tcl
View File

@ -56,7 +56,67 @@ tags "modules" {
}
}
tags {repl} {
test {diskless loading short read with module} {
start_server [list overrides [list loadmodule "$testmodule"]] {
set replica [srv 0 client]
set replica_host [srv 0 host]
set replica_port [srv 0 port]
start_server [list overrides [list loadmodule "$testmodule"]] {
set master [srv 0 client]
set master_host [srv 0 host]
set master_port [srv 0 port]
# TODO: test short read handling
# Set master and replica to use diskless replication
$master config set repl-diskless-sync yes
$master config set rdbcompression no
$replica config set repl-diskless-load swapdb
for {set k 0} {$k < 30} {incr k} {
r testrdb.set.key key$k [string repeat A [expr {int(rand()*1000000)}]]
}
# Start the replication process...
$master config set repl-diskless-sync-delay 0
$replica replicaof $master_host $master_port
# kill the replication at various points
set attempts 3
if {$::accurate} { set attempts 10 }
for {set i 0} {$i < $attempts} {incr i} {
# wait for the replica to start reading the rdb
# using the log file since the replica only responds to INFO once in 2mb
wait_for_log_message -1 "*Loading DB in memory*" 5 2000 1
# add some additional random sleep so that we kill the master on a different place each time
after [expr {int(rand()*100)}]
# kill the replica connection on the master
set killed [$master client kill type replica]
if {[catch {
set res [wait_for_log_message -1 "*Internal error in RDB*" 5 100 10]
if {$::verbose} {
puts $res
}
}]} {
puts "failed triggering short read"
# force the replica to try another full sync
$master client kill type replica
$master set asdf asdf
# the side effect of resizing the backlog is that it is flushed (16k is the min size)
$master config set repl-backlog-size [expr {16384 + $i}]
}
# wait for loading to stop (fail)
wait_for_condition 100 10 {
[s -1 loading] eq 0
} else {
fail "Replica didn't disconnect"
}
}
# enable fast shutdown
$master config set rdb-key-save-delay 0
}
}
}
}
}