feature: added the "get_keys" method for the shared dictionaries for fetching all the (or the specified number of) keys (default to 1024 keys). thanks Brian Akins for the patch in pull \#170.

src/ngx_http_lua_shdict.c

@@ -24,6 +24,7 @@ static int ngx_http_lua_shdict_incr(lua_State *L);
 static int ngx_http_lua_shdict_delete(lua_State *L);
 static int ngx_http_lua_shdict_flush_all(lua_State *L);
 static int ngx_http_lua_shdict_flush_expired(lua_State *L);
+static int ngx_http_lua_shdict_get_keys(lua_State *L);
 
 
 #define NGX_HTTP_LUA_SHDICT_ADD         0x0001
@@ -282,7 +283,7 @@ ngx_http_lua_inject_shdict_api(ngx_http_lua_main_conf_t *lmcf, lua_State *L)
         lua_createtable(L, 0, lmcf->shm_zones->nelts /* nrec */);
                 /* ngx.shared */
 
-        lua_createtable(L, 0 /* narr */, 9 /* nrec */); /* shared mt */
+        lua_createtable(L, 0 /* narr */, 10 /* nrec */); /* shared mt */
 
         lua_pushcfunction(L, ngx_http_lua_shdict_get);
         lua_setfield(L, -2, "get");
@@ -308,6 +309,9 @@ ngx_http_lua_inject_shdict_api(ngx_http_lua_main_conf_t *lmcf, lua_State *L)
         lua_pushcfunction(L, ngx_http_lua_shdict_flush_expired);
         lua_setfield(L, -2, "flush_expired");
 
+        lua_pushcfunction(L, ngx_http_lua_shdict_get_keys);
+        lua_setfield(L, -2, "get_keys");
+
         lua_pushvalue(L, -1); /* shared mt mt */
         lua_setfield(L, -2, "__index"); /* shared mt */
 
@@ -617,6 +621,104 @@ ngx_http_lua_shdict_flush_expired(lua_State *L)
 }
 
 
+/*
+ * This trades CPU for memory. This is potentially slow. O(2n)
+ */
+
+static int
+ngx_http_lua_shdict_get_keys(lua_State *L)
+{
+    ngx_queue_t                 *q, *prev;
+    ngx_http_lua_shdict_node_t  *sd;
+    ngx_http_lua_shdict_ctx_t   *ctx;
+    ngx_shm_zone_t              *zone;
+    ngx_time_t                  *tp;
+    int                          total = 0;
+    int                          attempts = 1024;
+    uint64_t                     now;
+    int                          n;
+
+    n = lua_gettop(L);
+
+    if (n != 1 && n != 2) {
+        return luaL_error(L, "expecting 1 or 2 argument(s), "
+                          "but saw %d", n);
+    }
+
+    luaL_checktype(L, 1, LUA_TLIGHTUSERDATA);
+
+    zone = lua_touserdata(L, 1);
+    if (zone == NULL) {
+        return luaL_error(L, "bad user data for the ngx_shm_zone_t pointer");
+    }
+
+    if (n == 2) {
+        attempts = luaL_checknumber(L, 2);
+    }
+
+    ctx = zone->data;
+
+    ngx_shmtx_lock(&ctx->shpool->mutex);
+
+    if (ngx_queue_empty(&ctx->sh->queue)) {
+        ngx_shmtx_unlock(&ctx->shpool->mutex);
+        lua_createtable(L, 0, 0);
+        return 1;
+    }
+
+    tp = ngx_timeofday();
+
+    now = (uint64_t) tp->sec * 1000 + tp->msec;
+
+    /* first run through: get total number of elements we need to allocate */
+
+    q = ngx_queue_last(&ctx->sh->queue);
+
+    while (q != ngx_queue_sentinel(&ctx->sh->queue)) {
+        prev = ngx_queue_prev(q);
+
+        sd = ngx_queue_data(q, ngx_http_lua_shdict_node_t, queue);
+
+        if (sd->expires == 0 || sd->expires > now) {
+            total++;
+            if (attempts && total == attempts) {
+                break;
+            }
+        }
+
+        q = prev;
+    }
+
+    lua_createtable(L, total, 0);
+
+    /* second run through: add keys to table */
+
+    total = 0;
+    q = ngx_queue_last(&ctx->sh->queue);
+
+    while (q != ngx_queue_sentinel(&ctx->sh->queue)) {
+        prev = ngx_queue_prev(q);
+
+        sd = ngx_queue_data(q, ngx_http_lua_shdict_node_t, queue);
+
+        if (sd->expires == 0 || sd->expires > now) {
+            lua_pushlstring(L, (char *) sd->data, sd->key_len);
+            lua_rawseti(L, -2, ++total);
+            if (attempts && total == attempts) {
+                break;
+            }
+        }
+
+        q = prev;
+    }
+
+    ngx_shmtx_unlock(&ctx->shpool->mutex);
+
+    /* table is at top of stack */
+    return 1;
+}
+
+
 static int
 ngx_http_lua_shdict_add(lua_State *L)
 {

t/043-shdict.t

@@ -1172,3 +1172,198 @@ GET /t
 --- response_body
 0
 
+
+
+=== TEST 49: list all keys in a shdict
+--- http_config
+    lua_shared_dict dogs 1m;
+--- config
+    location = /t {
+        content_by_lua '
+            local dogs = ngx.shared.dogs
+
+            dogs:set("bah", "y", 0)
+            dogs:set("bar", "z", 0)
+            local keys = dogs:get_keys()
+            ngx.say(#keys)
+            table.sort(keys)
+            for _,k in ipairs(keys) do
+                ngx.say(k)
+            end
+        ';
+    }
+--- request
+GET /t
+--- response_body
+2
+bah
+bar
+
+
+
+=== TEST 50: list keys in a shdict with limit
+--- http_config
+    lua_shared_dict dogs 1m;
+--- config
+    location = /t {
+        content_by_lua '
+            local dogs = ngx.shared.dogs
+
+            dogs:set("bah", "y", 0)
+            dogs:set("bar", "z", 0)
+            local keys = dogs:get_keys(1)
+            ngx.say(#keys)
+        ';
+    }
+--- request
+GET /t
+--- response_body
+1
+
+
+
+=== TEST 51: list all keys in a shdict with expires
+--- http_config
+    lua_shared_dict dogs 1m;
+--- config
+    location = /t {
+        content_by_lua '
+            local dogs = ngx.shared.dogs
+            dogs:set("foo", "x", 1)
+            dogs:set("bah", "y", 0)
+            dogs:set("bar", "z", 100)
+
+            ngx.sleep(1.5)
+
+            local keys = dogs:get_keys()
+            ngx.say(#keys)
+        ';
+    }
+--- request
+GET /t
+--- response_body
+2
+
+
+
+=== TEST 52: list keys in a shdict with limit larger than number of keys
+--- http_config
+    lua_shared_dict dogs 1m;
+--- config
+    location = /t {
+        content_by_lua '
+            local dogs = ngx.shared.dogs
+
+            dogs:set("bah", "y", 0)
+            dogs:set("bar", "z", 0)
+            local keys = dogs:get_keys(3)
+            ngx.say(#keys)
+        ';
+    }
+--- request
+GET /t
+--- response_body
+2
+
+
+
+=== TEST 53: list keys in an empty shdict
+--- http_config
+    lua_shared_dict dogs 1m;
+--- config
+    location = /t {
+        content_by_lua '
+            local dogs = ngx.shared.dogs
+            local keys = dogs:get_keys()
+            ngx.say(#keys)
+        ';
+    }
+--- request
+GET /t
+--- response_body
+0
+
+
+
+=== TEST 54: list keys in an empty shdict with a limit
+--- http_config
+    lua_shared_dict dogs 1m;
+--- config
+    location = /t {
+        content_by_lua '
+            local dogs = ngx.shared.dogs
+            local keys = dogs:get_keys(4)
+            ngx.say(#keys)
+        ';
+    }
+--- request
+GET /t
+--- response_body
+0
+
+
+
+=== TEST 55: list all keys in a shdict with all keys expired
+--- http_config
+    lua_shared_dict dogs 1m;
+--- config
+    location = /t {
+        content_by_lua '
+            local dogs = ngx.shared.dogs
+            dogs:set("foo", "x", 1)
+            dogs:set("bah", "y", 1)
+            dogs:set("bar", "z", 1)
+
+            ngx.sleep(1.5)
+
+            local keys = dogs:get_keys()
+            ngx.say(#keys)
+        ';
+    }
+--- request
+GET /t
+--- response_body
+0
+
+
+
+=== TEST 56: list all keys in a shdict with more than 1024 keys with no limit set
+--- http_config
+    lua_shared_dict dogs 1m;
+--- config
+    location = /t {
+        content_by_lua '
+            local dogs = ngx.shared.dogs
+            for i=1,2048 do
+                dogs:set(tostring(i), i)
+            end
+            local keys = dogs:get_keys()
+            ngx.say(#keys)
+        ';
+    }
+--- request
+GET /t
+--- response_body
+1024
+
+
+
+=== TEST 57: list all keys in a shdict with more than 1024 keys with 0 limit set
+--- http_config
+    lua_shared_dict dogs 1m;
+--- config
+    location = /t {
+        content_by_lua '
+            local dogs = ngx.shared.dogs
+            for i=1,2048 do
+                dogs:set(tostring(i), i)
+            end
+            local keys = dogs:get_keys(0)
+            ngx.say(#keys)
+        ';
+    }
+--- request
+GET /t
+--- response_body
+2048
+

t/062-count.t

@@ -279,7 +279,7 @@ n = 4
 --- request
 GET /test
 --- response_body
-n = 9
+n = 10
 --- no_error_log
 [error]