Modules: Test RedisModule_BlockClientOnKeys

runtest-moduleapi

@@ -21,4 +21,5 @@ $TCLSH tests/test_helper.tcl \
 --single unit/moduleapi/propagate \
 --single unit/moduleapi/hooks \
 --single unit/moduleapi/misc \
+--single unit/moduleapi/blockonkeys \
 "${@}"

tests/modules/Makefile

@@ -18,7 +18,8 @@ TEST_MODULES = \
     infotest.so \
     propagate.so \
     misc.so \
-    hooks.so
+    hooks.so \
+    blockonkeys.so
 
 .PHONY: all
 

tests/modules/blockonkeys.c

@@ -0,0 +1,261 @@
+#define REDISMODULE_EXPERIMENTAL_API
+#include "redismodule.h"
+
+#include <string.h>
+#include <assert.h>
+#include <unistd.h>
+
+#define LIST_SIZE 1024
+
+typedef struct {
+    long long list[LIST_SIZE];
+    long long length;
+} fsl_t; /* Fixed-size list */
+
+static RedisModuleType *fsltype = NULL;
+
+fsl_t *fsl_type_create() {
+    fsl_t *o;
+    o = RedisModule_Alloc(sizeof(*o));
+    o->length = 0;
+    return o;
+}
+
+void fsl_type_free(fsl_t *o) {
+    RedisModule_Free(o);
+}
+
+/* ========================== "fsltype" type methods ======================= */
+
+void *fsl_rdb_load(RedisModuleIO *rdb, int encver) {
+    if (encver != 0) {
+        return NULL;
+    }
+    fsl_t *fsl = fsl_type_create();
+    fsl->length = RedisModule_LoadUnsigned(rdb);
+    for (long long i = 0; i < fsl->length; i++)
+        fsl->list[i] = RedisModule_LoadSigned(rdb);
+    return fsl;
+}
+
+void fsl_rdb_save(RedisModuleIO *rdb, void *value) {
+    fsl_t *fsl = value;
+    RedisModule_SaveUnsigned(rdb,fsl->length);
+    for (long long i = 0; i < fsl->length; i++)
+        RedisModule_SaveSigned(rdb, fsl->list[i]);
+}
+
+void fsl_aofrw(RedisModuleIO *aof, RedisModuleString *key, void *value) {
+    fsl_t *fsl = value;
+    for (long long i = 0; i < fsl->length; i++)
+        RedisModule_EmitAOF(aof, "FSL.PUSH","sl", key, fsl->list[i]);
+}
+
+void fsl_free(void *value) {
+    fsl_type_free(value);
+}
+
+/* ========================== helper methods ======================= */
+
+int get_fsl(RedisModuleCtx *ctx, RedisModuleString *keyname, int mode, int create, fsl_t **fsl, int reply_on_failure) {
+    RedisModuleKey *key = RedisModule_OpenKey(ctx, keyname, mode);
+
+    int type = RedisModule_KeyType(key);
+    if (type != REDISMODULE_KEYTYPE_EMPTY && RedisModule_ModuleTypeGetType(key) != fsltype) {
+        RedisModule_CloseKey(key);
+        if (reply_on_failure)
+            RedisModule_ReplyWithError(ctx, REDISMODULE_ERRORMSG_WRONGTYPE);
+        return 0;
+    }
+
+    /* Create an empty value object if the key is currently empty. */
+    if (type == REDISMODULE_KEYTYPE_EMPTY) {
+        if (!create) {
+            /* Key is empty but we cannot create */
+            RedisModule_CloseKey(key);
+            *fsl = NULL;
+            return 1;
+        }
+        *fsl = fsl_type_create();
+        RedisModule_ModuleTypeSetValue(key, fsltype, *fsl);
+    } else {
+        *fsl = RedisModule_ModuleTypeGetValue(key);
+    }
+
+    RedisModule_CloseKey(key);
+    return 1;
+}
+
+/* ========================== commands ======================= */
+
+/* FSL.PUSH <key> <int> - Push an integer to the fixed-size list (to the right).
+ * It must be greater than the element in the head of the list. */
+int fsl_push(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    if (argc != 3)
+        return RedisModule_WrongArity(ctx);
+
+    long long ele;
+    if (RedisModule_StringToLongLong(argv[2],&ele) != REDISMODULE_OK)
+        return RedisModule_ReplyWithError(ctx,"ERR invalid integer");
+
+    fsl_t *fsl;
+    if (!get_fsl(ctx, argv[1], REDISMODULE_WRITE, 1, &fsl, 1))
+        return REDISMODULE_OK;
+
+    if (fsl->length == LIST_SIZE)
+        return RedisModule_ReplyWithError(ctx,"ERR list is full");
+
+    if (fsl->length != 0 && fsl->list[fsl->length-1] >= ele)
+        return RedisModule_ReplyWithError(ctx,"ERR new element has to be greater than the head element");
+
+    fsl->list[fsl->length++] = ele;
+
+    if (fsl->length >= 2)
+        RedisModule_SignalKeyAsReady(ctx, argv[1]);
+
+    return RedisModule_ReplyWithSimpleString(ctx, "OK");
+}
+
+int bpop2_reply_callback(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    REDISMODULE_NOT_USED(argv);
+    REDISMODULE_NOT_USED(argc);
+    RedisModuleString *keyname = RedisModule_GetBlockedClientReadyKey(ctx);
+
+    fsl_t *fsl;
+    if (!get_fsl(ctx, keyname, REDISMODULE_READ, 0, &fsl, 0))
+        return REDISMODULE_ERR;
+
+    if (!fsl || fsl->length < 2)
+        return REDISMODULE_ERR;
+
+    RedisModule_ReplyWithArray(ctx, 2);
+    RedisModule_ReplyWithLongLong(ctx, fsl->list[--fsl->length]);
+    RedisModule_ReplyWithLongLong(ctx, fsl->list[--fsl->length]);
+    return REDISMODULE_OK;
+}
+
+int bpop2_timeout_callback(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    REDISMODULE_NOT_USED(argv);
+    REDISMODULE_NOT_USED(argc);
+    return RedisModule_ReplyWithSimpleString(ctx, "Request timedout");
+}
+
+
+/* FSL.BPOP2 <key> <timeout> - Block clients until list has two or more elements.
+ * When that happens, unblock client and pop the last two elements (from the right). */
+int fsl_bpop2(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    if (argc != 3)
+        return RedisModule_WrongArity(ctx);
+
+    long long timeout;
+    if (RedisModule_StringToLongLong(argv[2],&timeout) != REDISMODULE_OK || timeout < 0)
+        return RedisModule_ReplyWithError(ctx,"ERR invalid timeout");
+
+    fsl_t *fsl;
+    if (!get_fsl(ctx, argv[1], REDISMODULE_READ, 0, &fsl, 1))
+        return REDISMODULE_OK;
+
+    if (!fsl || fsl->length < 2) {
+        /* Key is empty or has <2 elements, we must block */
+        RedisModule_BlockClientOnKeys(ctx, bpop2_reply_callback, bpop2_timeout_callback,
+                                      NULL, timeout, &argv[1], 1, NULL);
+    } else {
+        RedisModule_ReplyWithArray(ctx, 2);
+        RedisModule_ReplyWithLongLong(ctx, fsl->list[--fsl->length]);
+        RedisModule_ReplyWithLongLong(ctx, fsl->list[--fsl->length]);
+    }
+
+    return REDISMODULE_OK;
+}
+
+int bpopgt_reply_callback(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    REDISMODULE_NOT_USED(argv);
+    REDISMODULE_NOT_USED(argc);
+    RedisModuleString *keyname = RedisModule_GetBlockedClientReadyKey(ctx);
+    long long gt = (long long)RedisModule_GetBlockedClientPrivateData(ctx);
+
+    fsl_t *fsl;
+    if (!get_fsl(ctx, keyname, REDISMODULE_READ, 0, &fsl, 0))
+        return REDISMODULE_ERR;
+
+    if (!fsl || fsl->list[fsl->length-1] <= gt)
+        return REDISMODULE_ERR;
+
+    RedisModule_ReplyWithLongLong(ctx, fsl->list[--fsl->length]);
+    return REDISMODULE_OK;
+}
+
+int bpopgt_timeout_callback(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    REDISMODULE_NOT_USED(argv);
+    REDISMODULE_NOT_USED(argc);
+    return RedisModule_ReplyWithSimpleString(ctx, "Request timedout");
+}
+
+void bpopgt_free_privdata(RedisModuleCtx *ctx, void *privdata) {
+    /* Nothing to do because privdata is actually a 'long long',
+     * not a pointer to the heap */
+    REDISMODULE_NOT_USED(ctx);
+    REDISMODULE_NOT_USED(privdata);
+}
+
+/* FSL.BPOPGT <key> <gt> <timeout> - Block clients until list has an element greater than <gt>.
+ * When that happens, unblock client and pop the last element (from the right). */
+int fsl_bpopgt(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    if (argc != 4)
+        return RedisModule_WrongArity(ctx);
+
+    long long gt;
+    if (RedisModule_StringToLongLong(argv[2],&gt) != REDISMODULE_OK)
+        return RedisModule_ReplyWithError(ctx,"ERR invalid integer");
+
+    long long timeout;
+    if (RedisModule_StringToLongLong(argv[3],&timeout) != REDISMODULE_OK || timeout < 0)
+        return RedisModule_ReplyWithError(ctx,"ERR invalid timeout");
+
+    fsl_t *fsl;
+    if (!get_fsl(ctx, argv[1], REDISMODULE_READ, 0, &fsl, 1))
+        return REDISMODULE_OK;
+
+    if (!fsl || fsl->list[fsl->length-1] <= gt) {
+        /* Key is empty or has <2 elements, we must block */
+        RedisModule_BlockClientOnKeys(ctx, bpopgt_reply_callback, bpopgt_timeout_callback,
+                                      bpopgt_free_privdata, timeout, &argv[1], 1, (void*)gt);
+    } else {
+        RedisModule_ReplyWithLongLong(ctx, fsl->list[--fsl->length]);
+    }
+
+    return REDISMODULE_OK;
+}
+
+int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    REDISMODULE_NOT_USED(argv);
+    REDISMODULE_NOT_USED(argc);
+
+    if (RedisModule_Init(ctx, "blockonkeys", 1, REDISMODULE_APIVER_1)== REDISMODULE_ERR)
+        return REDISMODULE_ERR;
+
+    RedisModuleTypeMethods tm = {
+        .version = REDISMODULE_TYPE_METHOD_VERSION,
+        .rdb_load = fsl_rdb_load,
+        .rdb_save = fsl_rdb_save,
+        .aof_rewrite = fsl_aofrw,
+        .mem_usage = NULL,
+        .free = fsl_free,
+        .digest = NULL
+    };
+
+    fsltype = RedisModule_CreateDataType(ctx, "fsltype_t", 0, &tm);
+    if (fsltype == NULL)
+        return REDISMODULE_ERR;
+
+    if (RedisModule_CreateCommand(ctx,"fsl.push",fsl_push,"",0,0,0) == REDISMODULE_ERR)
+        return REDISMODULE_ERR;
+
+    if (RedisModule_CreateCommand(ctx,"fsl.bpop2",fsl_bpop2,"",0,0,0) == REDISMODULE_ERR)
+        return REDISMODULE_ERR;
+
+    if (RedisModule_CreateCommand(ctx,"fsl.bpopgt",fsl_bpopgt,"",0,0,0) == REDISMODULE_ERR)
+        return REDISMODULE_ERR;
+
+    return REDISMODULE_OK;
+}

tests/unit/moduleapi/blockonkeys.tcl

@@ -0,0 +1,85 @@
+set testmodule [file normalize tests/modules/blockonkeys.so]
+
+start_server {tags {"modules"}} {
+    r module load $testmodule
+
+    test {Module client blocked on keys (no metadata): No block} {
+        r del k
+        r fsl.push k 33
+        r fsl.push k 34
+        r fsl.bpop2 k 0
+    } {34 33}
+
+    test {Module client blocked on keys (no metadata): Timeout} {
+        r del k
+        set rd [redis_deferring_client]
+        r fsl.push k 33
+        $rd fsl.bpop2 k 1
+        assert_equal {Request timedout} [$rd read]
+    }
+
+    test {Module client blocked on keys (no metadata): Blocked, case 1} {
+        r del k
+        set rd [redis_deferring_client]
+        r fsl.push k 33
+        $rd fsl.bpop2 k 0
+        r fsl.push k 34
+        assert_equal {34 33} [$rd read]
+    }
+
+    test {Module client blocked on keys (no metadata): Blocked, case 2} {
+        r del k
+        set rd [redis_deferring_client]
+        r fsl.push k 33
+        r fsl.push k 34
+        $rd fsl.bpop2 k 0
+        assert_equal {34 33} [$rd read]
+    }
+
+    test {Module client blocked on keys (with metadata): No block} {
+        r del k
+        r fsl.push k 34
+        r fsl.bpopgt k 30 0
+    } {34}
+
+    test {Module client blocked on keys (with metadata): Timeout} {
+        r del k
+        set rd [redis_deferring_client]
+        r fsl.push k 33
+        $rd fsl.bpopgt k 35 1
+        assert_equal {Request timedout} [$rd read]
+    }
+
+    test {Module client blocked on keys (with metadata): Blocked, case 1} {
+        r del k
+        set rd [redis_deferring_client]
+        r fsl.push k 33
+        $rd fsl.bpopgt k 33 0
+        r fsl.push k 34
+        assert_equal {34} [$rd read]
+    }
+
+    test {Module client blocked on keys (with metadata): Blocked, case 2} {
+        r del k
+        set rd [redis_deferring_client]
+        $rd fsl.bpopgt k 35 0
+        r fsl.push k 33
+        r fsl.push k 34
+        r fsl.push k 35
+        r fsl.push k 36
+        assert_equal {36} [$rd read]
+    }
+
+    test {Module client blocked on keys does not wake up on wrong type} {
+        r del k
+        set rd [redis_deferring_client]
+        $rd fsl.bpop2 k 0
+        r lpush k 12
+        r lpush k 13
+        r lpush k 14
+        r del k
+        r fsl.push k 33
+        r fsl.push k 34
+        assert_equal {34 33} [$rd read]
+    }
+}