feature: allow ngx.sleep to be used blockingly in non-yieldable phases

Allow ngx.sleep everywhere simplify the application's logic.
Now we don't need to write a fallback if the same function need to be
run in non-yieldable phases.

Close openresty#1730.

README.markdown

@@ -5621,14 +5621,17 @@ ngx.sleep
 
 **syntax:** *ngx.sleep(seconds)*
 
-**context:** *rewrite_by_lua*, access_by_lua*, content_by_lua*, ngx.timer.*, ssl_certificate_by_lua*, ssl_session_fetch_by_lua**
+**context:** *init_by_lua*, init_worker_by_lua*, set_by_lua*, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.*, balancer_by_lua*, ssl_certificate_by_lua*, ssl_session_fetch_by_lua*, ssl_session_store_by_lua*, exit_worker_by_lua**
 
-Sleeps for the specified seconds without blocking. One can specify time resolution up to 0.001 seconds (i.e., one millisecond).
+Sleeps for the specified seconds without blocking in yieldable phases or blockingly in other phases.
+One can specify time resolution up to 0.001 seconds (i.e., one millisecond).
 
 Behind the scene, this method makes use of the Nginx timers.
 
 Since the `0.7.20` release, The `0` time argument can also be specified.
 
+Since the `FIXME` release, this method can be used in non-yieldable phases blockingly.
+
 This method was introduced in the `0.5.0rc30` release.
 
 [Back to TOC](#nginx-api-for-lua)

doc/HttpLuaModule.wiki

@@ -4720,14 +4720,17 @@ Since <code>v0.8.3</code> this function returns <code>1</code> on success, or re
 
 '''syntax:''' ''ngx.sleep(seconds)''
 
-'''context:''' ''rewrite_by_lua*, access_by_lua*, content_by_lua*, ngx.timer.*, ssl_certificate_by_lua*, ssl_session_fetch_by_lua*''
+'''context:''' ''init_by_lua*, init_worker_by_lua*, set_by_lua*, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.*, balancer_by_lua*, ssl_certificate_by_lua*, ssl_session_fetch_by_lua*, ssl_session_store_by_lua*, exit_worker_by_lua*''
 
-Sleeps for the specified seconds without blocking. One can specify time resolution up to 0.001 seconds (i.e., one millisecond).
+Sleeps for the specified seconds without blocking in yieldable phases or blockingly in other phases.
+One can specify time resolution up to 0.001 seconds (i.e., one millisecond).
 
 Behind the scene, this method makes use of the Nginx timers.
 
 Since the <code>0.7.20</code> release, The <code>0</code> time argument can also be specified.
 
+Since the <code>FIXME</code> release, this method can be used in non-yieldable phases blockingly.
+
 This method was introduced in the <code>0.5.0rc30</code> release.
 
 == ngx.escape_uri ==

src/ngx_http_lua_sleep.c

@@ -36,23 +36,34 @@ ngx_http_lua_ngx_sleep(lua_State *L)
         return luaL_error(L, "attempt to pass %d arguments, but accepted 1", n);
     }
 
-    r = ngx_http_lua_get_req(L);
-    if (r == NULL) {
-        return luaL_error(L, "no request found");
-    }
-
     delay = (ngx_int_t) (luaL_checknumber(L, 1) * 1000);
 
     if (delay < 0) {
         return luaL_error(L, "invalid sleep duration \"%d\"", delay);
     }
 
+    r = ngx_http_lua_get_req(L);
+    if (r == NULL) {
+        /* init_by_lua phase */
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
+                       "lua ready to sleep for %d ms", delay);
+
+        ngx_msleep(delay);
+        return 0;
+    }
+
     ctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);
     if (ctx == NULL) {
         return luaL_error(L, "no request ctx found");
     }
 
-    ngx_http_lua_check_context(L, ctx, NGX_HTTP_LUA_CONTEXT_YIELDABLE);
+    if (!(ctx->context & NGX_HTTP_LUA_CONTEXT_YIELDABLE)) {
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "lua ready to sleep for %d ms", delay);
+
+        ngx_msleep(delay);
+        return 0;
+    }
 
     coctx = ctx->cur_co_ctx;
     if (coctx == NULL) {

t/077-sleep.t

@@ -9,7 +9,7 @@ log_level('debug');
 
 repeat_each(2);
 
-plan tests => repeat_each() * 71;
+plan tests => repeat_each() * (blocks() * 4);
 
 #no_diff();
 no_long_string();
@@ -237,21 +237,20 @@ lua sleep timer expired: "/test?"
 
 
 
-=== TEST 10: ngx.sleep unavailable in log_by_lua
+=== TEST 10: ngx.sleep available in log_by_lua
 --- config
     location /t {
         echo hello;
-        log_by_lua '
-            ngx.sleep(0.1)
-        ';
+        log_by_lua_block {
+            ngx.sleep(0.001)
+        }
     }
 --- request
 GET /t
 --- response_body
 hello
---- wait: 0.1
 --- error_log
-API disabled in the context of log_by_lua*
+lua ready to sleep for 1 ms
 
 
 
@@ -500,3 +499,66 @@ f end
 worker cycle
 e?poll timer: 0
 /
+
+
+
+=== TEST 18: ngx.sleep(0) in no-yieldable phases
+--- config
+    location /t {
+        echo hello;
+        log_by_lua_block {
+            ngx.sleep(0)
+        }
+    }
+--- request
+GET /t
+--- response_body
+hello
+--- error_log
+lua ready to sleep for 0 ms
+
+
+
+=== TEST 19: ngx.sleep available in init_worker_by_lua
+--- http_config
+    init_worker_by_lua_block {
+        local start = ngx.now()
+        ngx.sleep(0.1)
+        ngx.update_time()
+        package.loaded.gap = ngx.now() - start
+    }
+--- config
+    location /t {
+        content_by_lua_block {
+            ngx.say(package.loaded.gap >= 0.1)
+        }
+    }
+--- request
+GET /t
+--- no_error_log
+[error]
+--- response_body
+true
+
+
+
+=== TEST 20: ngx.sleep available in init_by_lua
+--- http_config
+    init_by_lua_block {
+        local start = ngx.now()
+        ngx.sleep(0.1)
+        ngx.update_time()
+        package.loaded.gap = ngx.now() - start
+    }
+--- config
+    location /t {
+        content_by_lua_block {
+            ngx.say(package.loaded.gap >= 0.1)
+        }
+    }
+--- request
+GET /t
+--- no_error_log
+[error]
+--- response_body
+true