refactor(proxy-wasm) improve pwexec resurrection and instance lifecycle

The main goal of this overhaul is to simplify `on_context_create`, make it fully re-entrant *and* properly handle instance recycling at the same time. The way to do so, in my opinion, was to move `pwexec` creation where `rexec` already was. In other words, always lookup the context id in the instance rbtree, and if not found, create it. This means that surrounding code also needed big overhauls. It also removes the reference counting poor man's GC of the older implementation. The code became really ugly by then so I took the time to also review this module's code structure instead of making a *very* ugly commit. This new ngx_proxy_wasm.c file should be much easier to read and follow now. One change I do not fully like is moving the `next_id` to a global counter, but we do not have a "global proxy-wasm conf" object yet. I also started thinking about pre-allocating a number of `pwexecs` (like `worker_connections`) and use free/busy queue that all filter chains can dip into to get a context id + context memory zone. Perhaps for a later time.
Kong · Sep 29, 2023 · ce24de9 · ce24de9
1 parent 1e14e46
commit ce24de9
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Showing 14 changed files with 917 additions and 827 deletions.
diff --git a/src/common/proxy_wasm/ngx_proxy_wasm.c b/src/common/proxy_wasm/ngx_proxy_wasm.c
diff --git a/src/common/proxy_wasm/ngx_proxy_wasm.h b/src/common/proxy_wasm/ngx_proxy_wasm.h
@@ -195,6 +195,7 @@ struct ngx_proxy_wasm_exec_s {
     ngx_proxy_wasm_ctx_t              *parent;
     ngx_proxy_wasm_filter_t           *filter;
     ngx_proxy_wasm_instance_t         *ictx;
+    ngx_proxy_wasm_store_t            *store;
     ngx_event_t                       *ev;
 #ifdef NGX_WASM_HTTP
     ngx_http_proxy_wasm_dispatch_t    *call;
@@ -203,8 +204,8 @@ struct ngx_proxy_wasm_exec_s {
     /* flags */
 
     unsigned                           started:1;
-    unsigned                           ecode_logged:1;
     unsigned                           in_tick:1;
+    unsigned                           ecode_logged:1;
 };
 
 
@@ -259,9 +260,7 @@ struct ngx_proxy_wasm_ctx_s {
 
 
 struct ngx_proxy_wasm_instance_s {
-    ngx_uint_t                         next_id;
-    ngx_uint_t                         nrefs;
-    ngx_queue_t                        q;
+    ngx_queue_t                        q;                 /* store busy/free/sweep */
     ngx_rbtree_t                       tree_ctxs;
     ngx_rbtree_t                       root_ctxs;
     ngx_rbtree_node_t                  sentinel_ctxs;
@@ -272,9 +271,9 @@ struct ngx_proxy_wasm_instance_s {
     ngx_pool_t                        *pool;
     ngx_log_t                         *log;
 
-    /* swap */
+    /* pwexec references */
 
-    ngx_proxy_wasm_exec_t             *pwexec;
+    ngx_proxy_wasm_exec_t             *pwexec;            /* current pwexec */
 };
 
 
@@ -303,6 +302,7 @@ struct ngx_proxy_wasm_filter_s {
 
     ngx_uint_t                     id;
     ngx_uint_t                     max_pairs;
+    ngx_uint_t                     next_id;
 
     /**
      * SDK
@@ -379,30 +379,27 @@ struct ngx_proxy_wasm_filter_s {
 };
 
 
-/* root */
-void ngx_proxy_wasm_init(ngx_conf_t *cf);
-void ngx_proxy_wasm_exit();
-ngx_uint_t ngx_proxy_wasm_id(ngx_str_t *name, ngx_str_t *config,
-    uintptr_t data);
+/* root context */
+void ngx_proxy_wasm_init(ngx_conf_t *cf, ngx_proxy_wasm_store_t *gstore);
+void ngx_proxy_wasm_exit(ngx_proxy_wasm_store_t *gstore);
 ngx_int_t ngx_proxy_wasm_load(ngx_proxy_wasm_filter_t *filter, ngx_log_t *log);
 ngx_int_t ngx_proxy_wasm_start(ngx_cycle_t *cycle);
 
 
-/* ctx/store */
+/* stream context */
 ngx_proxy_wasm_ctx_t *ngx_proxy_wasm_ctx_alloc(ngx_pool_t *pool);
 ngx_proxy_wasm_ctx_t *ngx_proxy_wasm_ctx(ngx_uint_t *filter_ids,
     size_t nfilters, ngx_uint_t isolation, ngx_proxy_wasm_subsystem_t *subsys,
     void *data);
 void ngx_proxy_wasm_ctx_destroy(ngx_proxy_wasm_ctx_t *pwctx);
 ngx_int_t ngx_proxy_wasm_resume(ngx_proxy_wasm_ctx_t *pwctx,
     ngx_wasm_phase_t *phase, ngx_proxy_wasm_step_e step);
+ngx_proxy_wasm_err_e ngx_proxy_wasm_run_step(ngx_proxy_wasm_exec_t *pwexec,
+    ngx_proxy_wasm_step_e step);
+
+
+/* host handlers */
 ngx_wavm_ptr_t ngx_proxy_wasm_alloc(ngx_proxy_wasm_exec_t *pwexec, size_t size);
-void ngx_proxy_wasm_store_destroy(ngx_proxy_wasm_store_t *store);
-ngx_proxy_wasm_instance_t *ngx_proxy_wasm_get_instance(
-    ngx_proxy_wasm_filter_t *filter, ngx_proxy_wasm_store_t *store,
-    ngx_proxy_wasm_exec_t *pwexec, ngx_log_t *log);
-void ngx_proxy_wasm_release_instance(ngx_proxy_wasm_instance_t *ictx,
-    unsigned sweep);
 
 
 /* utils */
@@ -418,8 +415,6 @@ ngx_int_t ngx_proxy_wasm_pairs_unmarshal(ngx_proxy_wasm_exec_t *pwexec,
 unsigned ngx_proxy_wasm_marshal(ngx_proxy_wasm_exec_t *pwexec,
     ngx_list_t *list, ngx_array_t *extras, ngx_wavm_ptr_t *out,
     uint32_t *out_size, ngx_uint_t *truncated);
-ngx_proxy_wasm_err_e ngx_proxy_wasm_run_step(ngx_proxy_wasm_exec_t *pwexec,
-    ngx_proxy_wasm_instance_t *ictx, ngx_proxy_wasm_step_e step);
 
 
 static ngx_inline void

diff --git a/src/common/proxy_wasm/ngx_proxy_wasm_util.c b/src/common/proxy_wasm/ngx_proxy_wasm_util.c
@@ -193,14 +193,13 @@ ngx_proxy_wasm_log_error(ngx_uint_t level, ngx_log_t *log,
 void
 ngx_proxy_wasm_filter_tick_handler(ngx_event_t *ev)
 {
-    ngx_log_t                  *log = ev->log;
-    ngx_proxy_wasm_exec_t      *pwexec = ev->data;
+    ngx_proxy_wasm_err_e      ecode;
+    ngx_log_t                *log = ev->log;
+    ngx_proxy_wasm_exec_t    *pwexec = ev->data;
+    ngx_proxy_wasm_filter_t  *filter = pwexec->filter;
 #ifdef NGX_WASM_HTTP
-    ngx_proxy_wasm_ctx_t       *pwctx = pwexec->parent;
+    ngx_proxy_wasm_ctx_t     *pwctx = pwexec->parent;
 #endif
-    ngx_proxy_wasm_filter_t    *filter = pwexec->filter;
-    ngx_proxy_wasm_instance_t  *ictx;
-    ngx_proxy_wasm_err_e        ecode;
 
     dd("enter");
 
@@ -214,31 +213,16 @@ ngx_proxy_wasm_filter_tick_handler(ngx_event_t *ev)
         return;
     }
 
-    ictx = ngx_proxy_wasm_get_instance(filter, filter->store, pwexec,
-                                       filter->log);
-    if (ictx == NULL) {
-        ngx_wasm_log_error(NGX_LOG_ERR, log, 0,
-                           "tick_handler: no instance");
-        return;
-    }
-
 #ifdef NGX_WASM_HTTP
     pwctx->phase = ngx_wasm_phase_lookup(&ngx_http_wasm_subsystem,
                                          NGX_WASM_BACKGROUND_PHASE);
 #endif
-    pwexec->in_tick = 1;
-
-    ecode = ngx_proxy_wasm_run_step(pwexec, ictx, NGX_PROXY_WASM_STEP_TICK);
-
-    ngx_proxy_wasm_release_instance(ictx, 0);
 
+    ecode = ngx_proxy_wasm_run_step(pwexec, NGX_PROXY_WASM_STEP_TICK);
     if (ecode != NGX_PROXY_WASM_ERR_NONE) {
-        pwexec->ecode = ecode;
         return;
     }
 
-    pwexec->in_tick = 0;
-
     if (!ngx_exiting) {
         pwexec->ev = ngx_calloc(sizeof(ngx_event_t), log);
         if (pwexec->ev == NULL) {

diff --git a/src/http/ngx_http_wasm_module.c b/src/http/ngx_http_wasm_module.c
@@ -265,6 +265,7 @@ ngx_http_wasm_create_main_conf(ngx_conf_t *cf)
     mcf->vm = ngx_wasm_main_vm(cf->cycle);
 
     ngx_queue_init(&mcf->plans);
+    ngx_proxy_wasm_init(cf, &mcf->store);
 
     return mcf;
 }
@@ -281,9 +282,6 @@ ngx_http_wasm_init_main_conf(ngx_conf_t *cf, void *conf)
         return NGX_CONF_ERROR;
     }
 
-    ngx_proxy_wasm_init(cf);
-    ngx_proxy_wasm_store_init(&mcf->store, cf->pool);
-
     return NGX_CONF_OK;
 }
 
@@ -445,8 +443,7 @@ ngx_http_wasm_exit_process(ngx_cycle_t *cycle)
 
     mcf = ngx_http_cycle_get_module_main_conf(cycle, ngx_http_wasm_module);
     if (mcf) {
-        ngx_proxy_wasm_exit();
-        ngx_proxy_wasm_store_destroy(&mcf->store);
+        ngx_proxy_wasm_exit(&mcf->store);
 
         ngx_wasm_ops_destroy(mcf->ops);
     }

diff --git a/src/http/ngx_http_wasm_util.c b/src/http/ngx_http_wasm_util.c
@@ -411,8 +411,8 @@ ngx_http_wasm_ops_add_filter(ngx_wasm_ops_plan_t *plan,
         goto error;
     }
 
-    filter->pool = plan->pool;
     filter->log = vm->log;
+    filter->pool = store->pool;
     filter->store = store;
 
     if (config) {

diff --git a/src/http/proxy_wasm/ngx_http_proxy_wasm.h b/src/http/proxy_wasm/ngx_http_proxy_wasm.h
@@ -19,7 +19,7 @@ ngx_http_proxy_wasm_get_rctx(ngx_wavm_instance_t *instance)
 
     pwexec = ngx_proxy_wasm_instance2pwexec(instance);
     pwctx = pwexec->parent;
-    if (!pwctx) {
+    if (pwctx == NULL) {
         return NULL;
     }
 

diff --git a/src/http/proxy_wasm/ngx_http_proxy_wasm_dispatch.c b/src/http/proxy_wasm/ngx_http_proxy_wasm_dispatch.c
@@ -821,7 +821,7 @@ ngx_http_proxy_wasm_dispatch_resume_handler(ngx_wasm_socket_tcp_t *sock)
          */
         pwexec->call = call;
 
-        ecode = ngx_proxy_wasm_run_step(pwexec, pwexec->ictx,
+        ecode = ngx_proxy_wasm_run_step(pwexec,
                                         NGX_PROXY_WASM_STEP_DISPATCH_RESPONSE);
         if (ecode != NGX_PROXY_WASM_ERR_NONE) {
             goto error;

diff --git a/src/wasm/vm/ngx_wavm.c b/src/wasm/vm/ngx_wavm.c
@@ -1345,12 +1345,12 @@ ngx_wavm_instance_destroy(ngx_wavm_instance_t *instance)
     ngx_wavm_func_t    *func;
     ngx_wavm_module_t  *module = instance->module;
 
-    ngx_log_debug5(NGX_LOG_DEBUG_WASM,
+    ngx_log_debug6(NGX_LOG_DEBUG_WASM,
                    instance->log ? instance->log : ngx_cycle->log, 0,
                    "wasm freeing \"%V\" instance in \"%V\" vm"
-                   " (vm: %p, module: %p, instance: %p)",
+                   " (vm: %p, module: %p, instance: %p, trapped: %d)",
                    &module->name, module->vm->name,
-                   module->vm, module, instance);
+                   module->vm, module, instance, instance->trapped);
 
     if (instance->funcs.nelts) {
         for (i = 0; i < instance->funcs.nelts; i++) {

diff --git a/t/03-proxy_wasm/007-on_http_instance_isolation.t b/t/03-proxy_wasm/007-on_http_instance_isolation.t
@@ -94,10 +94,9 @@ Should recycle the global instance when trapped.
 (.*?(Uncaught RuntimeError: )?unreachable|\s*wasm trap: wasm `unreachable` instruction executed)[^#*]*
 \*\d+ .*? filter chain failed resuming: previous error \(instance trapped\)[^#*]*
 \*\d+ .*? filter freeing context #\d+ \(1\/2\)[^#*]*
-\*\d+ .*? filter freeing context #\d+ \(2\/2\)\Z/,
-qr/\A\*\d+ .*? filter freeing trapped instance[^#*]*
 \*\d+ wasm freeing "hostcalls" instance in "main" vm[^#*]*
-\*\d+ .*? filter new instance[^#*]*
+\*\d+ .*? filter freeing context #\d+ \(2\/2\)[^#*]*\Z/,
+qr/\A\*\d+ .*? filter new instance[^#*]*
 \*\d+ .*? filter reusing instance[^#*]*
 \*\d+ .*? filter 1\/2 resuming "on_request_headers" step in "rewrite" phase[^#*]*
 \*\d+ .*? filter 1\/2 resuming "on_response_headers" step in "header_filter" phase[^#*]*

diff --git a/t/03-proxy_wasm/hfuncs/114-proxy_set_http_request_body.t b/t/03-proxy_wasm/hfuncs/114-proxy_set_http_request_body.t
@@ -235,7 +235,7 @@ HelloWorld
     }
 
     location /log {
-        # cannot set request body
+        # not executed (subrequest)
         proxy_wasm hostcalls 'on=log \
                               test=/t/set_request_body';
         echo $request_body;
@@ -258,7 +258,6 @@ from_request_body
 --- grep_error_log_out eval
 qr/.*?host trap \(bad usage\): cannot set request body.*
 \[info\] .*? \*\d+ .*? filter chain failed resuming: previous error \(instance trapped\).*? subrequest: "\/response_headers".*
-\[info\] .*? \*\d+ .*? filter chain failed resuming: previous error \(instance trapped\).*? request: "GET \/t HTTP\/1\.1".*
 \z/
 --- no_error_log
 [alert]

diff --git a/t/03-proxy_wasm/hfuncs/119-proxy_properties_get_ngx.t b/t/03-proxy_wasm/hfuncs/119-proxy_properties_get_ngx.t
@@ -131,13 +131,8 @@ qr/\[info\] .*? property not found: n,/
 
 
 === TEST 5: proxy_wasm - get_property() ngx.* - not available on: tick (isolation: global)
-
 on_tick runs on the root context, so it does not have access to
 ngx_http_* calls.
-
-HTTP 500 since instance recycling happens on next request, and isolation
-is global (single instance for root/request).
-
 --- wasm_modules: hostcalls
 --- load_nginx_modules: ngx_http_echo_module
 --- config
@@ -146,7 +141,6 @@ is global (single instance for root/request).
         echo_sleep 0.150;
         echo ok;
     }
---- error_code: 500
 --- ignore_response_body
 --- error_log eval
 [

diff --git a/t/03-proxy_wasm/hfuncs/120-proxy_properties_get_host.t b/t/03-proxy_wasm/hfuncs/120-proxy_properties_get_host.t
@@ -97,7 +97,8 @@ TODO: is this behavior correct?
                               name=wasmx.nonexistent_property';
         echo ok;
     }
---- ignore_response_body
+--- response_body
+ok
 --- error_log eval
 qr/\[info\] .*? property not found: wasmx.nonexistent_property,/
 --- no_error_log
@@ -129,10 +130,6 @@ qr/\[info\] .*? property not found: was,/
 
 
 === TEST 4: proxy_wasm - get_property() wasmx - not available on: tick (isolation: global)
-
-HTTP 500 since instance recycling happens on next request, and isolation
-is global (single instance for root/request).
-
 --- wasm_modules: hostcalls
 --- load_nginx_modules: ngx_http_echo_module
 --- config
@@ -143,7 +140,6 @@ is global (single instance for root/request).
         echo_sleep 0.150;
         echo ok;
     }
---- error_code: 500
 --- ignore_response_body
 --- error_log eval
 [
@@ -152,15 +148,10 @@ is global (single instance for root/request).
     qr/\[crit\] .*? panicked at/,
     qr/unexpected status: 10/,
 ]
---- no_error_log
-[emerg]
 
 
 
 === TEST 5: proxy_wasm - get_property() wasmx - not available on: tick (isolation: stream)
-
-HTTP 200 since the root and request instances are different.
-
 --- wasm_modules: hostcalls
 --- load_nginx_modules: ngx_http_echo_module
 --- config

diff --git a/t/03-proxy_wasm/hfuncs/122-proxy_properties_set_host.t b/t/03-proxy_wasm/hfuncs/122-proxy_properties_set_host.t
@@ -139,10 +139,8 @@ Does not fail when the property is not found.
 
 
 === TEST 5: proxy_wasm - set_property() wasmx - not available on: tick (isolation: global)
-
-HTTP 500 since instance recycling happens on next request, and
-isolation is global (single instance for root/request).
-
+on_tick runs on the root context, so it does not have access to
+ngx_http_* calls.
 --- wasm_modules: hostcalls
 --- load_nginx_modules: ngx_http_echo_module
 --- config
@@ -157,7 +155,6 @@ isolation is global (single instance for root/request).
         echo_sleep 0.150;
         echo ok;
     }
---- error_code: 500
 --- ignore_response_body
 --- error_log eval
 [
@@ -172,12 +169,8 @@ isolation is global (single instance for root/request).
 
 
 === TEST 6: proxy_wasm - set_property() wasmx - not available on: tick (isolation: stream)
-
-HTTP 200 since the root and request instances are different.
-
 on_tick runs on the root context, so it does not have access to
 ngx_http_* calls.
-
 --- wasm_modules: hostcalls
 --- load_nginx_modules: ngx_http_echo_module
 --- config

diff --git a/t/03-proxy_wasm/hfuncs/123-proxy_properties_set_ngx.t b/t/03-proxy_wasm/hfuncs/123-proxy_properties_set_ngx.t
@@ -190,13 +190,8 @@ forward the NotFound status back to the caller.
 
 
 === TEST 7: proxy_wasm - set_property() ngx.* - not available on: tick (isolation: global)
-
 on_tick runs on the root context, so it does not have access to
 ngx_http_* calls.
-
-HTTP 500 since instance recycling happens on next
-request, and isolation is global (single instance for root/request)
-
 --- wasm_modules: hostcalls
 --- load_nginx_modules: ngx_http_echo_module
 --- config
@@ -211,7 +206,6 @@ request, and isolation is global (single instance for root/request)
         echo_sleep 0.150;
         echo ok;
     }
---- error_code: 500
 --- ignore_response_body
 --- error_log eval
 [