feat(proxy-wasm) foreign function support #626

casimiro · 2024-11-18T20:43:08Z

Foreign Function Support

The Proxy-Wasm spec defines the function proxy_call_foreign_function and the callback proxy_on_foreign_function that filter developers can use to invoke host specific functions, a.k.a. foreign functions, and receive callbacks.

A foreign function invoked with proxy_call_foreign_function may return its value immediately -- as part of the returned value of the proxy_call_foreign_function call; or it can return it later, writing it to the FOREIGN_FUNCTION_ARGUMENTS buffer, and invoking proxy_on_foreign_function with an id identifying the function initially called.

This PR adds support for the mechanism described above; and although the spec doesn't restrict when foreign functions can be called, in ngx_wasm_module they cannot be invoked from proxy_on_configure or proxy_on_vm_start.

DNS resolution

This PR also exposes the Lua DNS resolver through the resolve_lua foreign function.

This function expects the name to be resolved as its single argument. If the name can be resolved without performing any IO, the resolved address is put in the returned value of proxy_call_foreign_function.

If the resolver needs to forward the resolution request to a DNS server, the resolved address and the name itself are written to the FOREIGN_FUNCTION_ARGUMENTS buffer and the proxy_on_foreign_function callback is invoked with function_id 0, as soon as the address is returned from the server.

TODO

on_tick support
general review
update docs

codecov · 2024-11-19T22:03:15Z

Codecov Report

Attention: Patch coverage is 71.42857% with 66 lines in your changes missing coverage. Please review.

Project coverage is 90.45578%. Comparing base (9238d4a) to head (2ecb389).

Files with missing lines	Patch %	Lines
src/common/proxy_wasm/ngx_proxy_wasm_host.c	65.00000%	42 Missing ⚠️
src/common/proxy_wasm/ngx_proxy_wasm.c	54.54545%	10 Missing ⚠️
...ommon/proxy_wasm/ngx_proxy_wasm_foreign_callback.c	85.18519%	8 Missing ⚠️
src/http/ngx_http_wasm_util.c	80.00000%	3 Missing ⚠️
src/http/proxy_wasm/ngx_http_proxy_wasm.c	88.23529%	2 Missing ⚠️
src/http/proxy_wasm/ngx_http_proxy_wasm_dispatch.c	50.00000%	1 Missing ⚠️

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main        #626         +/-   ##
===================================================
- Coverage   90.84180%   90.45578%   -0.38603%     
===================================================
  Files             52          53          +1     
  Lines          11214       11431        +217     
===================================================
+ Hits           10187       10340        +153     
- Misses          1027        1091         +64

Files with missing lines	Coverage Δ
src/common/proxy_wasm/ngx_proxy_wasm.h	`92.30769% <ø> (ø)`
src/common/proxy_wasm/ngx_proxy_wasm_util.c	`94.25287% <100.00000%> (ø)`
src/http/proxy_wasm/ngx_http_proxy_wasm_dispatch.c	`91.95980% <50.00000%> (+0.27276%)`	⬆️
src/http/proxy_wasm/ngx_http_proxy_wasm.c	`93.30144% <88.23529%> (-0.44857%)`	⬇️
src/http/ngx_http_wasm_util.c	`86.95652% <80.00000%> (-0.27752%)`	⬇️
...ommon/proxy_wasm/ngx_proxy_wasm_foreign_callback.c	`85.18519% <85.18519%> (ø)`
src/common/proxy_wasm/ngx_proxy_wasm.c	`91.78228% <54.54545%> (-0.89532%)`	⬇️
src/common/proxy_wasm/ngx_proxy_wasm_host.c	`90.46673% <65.00000%> (-3.44533%)`	⬇️

... and 1 file with indirect coverage changes

Flag	Coverage Δ
unit	`90.40686% <81.00000%> (-0.17338%)`	⬇️
valgrind	`80.93180% <10.59908%> (-1.57678%)`	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

---- 🚨 Try these New Features:

Flaky Tests Detection - Detect and resolve failed and flaky tests

thibaultcha · 2024-11-21T19:43:34Z

src/common/proxy_wasm/ngx_proxy_wasm.h

 #ifdef NGX_WASM_HTTP
-    ngx_http_proxy_wasm_dispatch_t    *call;  /* swap pointer for host functions */
+    ngx_http_proxy_wasm_dispatch_t     *call;  /* swap pointer for host functions */


dispatch_call

thibaultcha · 2024-11-21T19:43:41Z

src/common/proxy_wasm/ngx_proxy_wasm.h

 #endif
-    ngx_queue_t                        calls;
+    ngx_queue_t                         calls;


dispatch_calls

thibaultcha · 2024-11-21T19:43:48Z

src/common/proxy_wasm/ngx_proxy_wasm.h

 #endif
-    ngx_queue_t                        calls;
+    ngx_queue_t                         calls;
+    ngx_proxy_wasm_foreign_cb_t        *fcallback;


foreign_call

thibaultcha · 2024-11-21T19:44:10Z

src/common/proxy_wasm/ngx_proxy_wasm.h

-    ngx_queue_t                        calls;
+    ngx_queue_t                         calls;
+    ngx_proxy_wasm_foreign_cb_t        *fcallback;
+    ngx_queue_t                         fcallbacks;


foreign_calls

thibaultcha · 2024-11-21T19:44:27Z

src/common/proxy_wasm/ngx_proxy_wasm.h

@@ -415,6 +424,9 @@ ngx_proxy_wasm_err_e ngx_proxy_wasm_run_step(ngx_proxy_wasm_exec_t *pwexec,
    ngx_proxy_wasm_step_e step);
 ngx_uint_t ngx_proxy_wasm_dispatch_calls_total(ngx_proxy_wasm_exec_t *pwexec);
 void ngx_proxy_wasm_dispatch_calls_cancel(ngx_proxy_wasm_exec_t *pwexec);
+ngx_uint_t ngx_proxy_wasm_foreign_callbacks_total(


foreign_calls_total
...

thibaultcha · 2024-11-21T19:44:37Z

src/common/proxy_wasm/ngx_proxy_wasm_foreign_callback.c

+void
+ngx_proxy_wasm_foreign_callback_destroy(ngx_proxy_wasm_foreign_cb_t *cb)
+{
+


Suggested change

thibaultcha · 2024-11-21T19:46:19Z

src/common/proxy_wasm/ngx_proxy_wasm_foreign_callback.c

+    ngx_wa_assert(pwexec);
+    ngx_wa_assert(size);
+
+    cl = ngx_alloc_chain_link(pwexec->pool);


ngx_wasm_chain_get_free_buf

thibaultcha · 2024-11-21T19:49:48Z

src/common/proxy_wasm/ngx_proxy_wasm_foreign_callback.c

+        return NGX_ERROR;
+    }
+
+    /* TODO: if size exceeds a threshold, split allocation into N buffers */


ngx_wa_assert(len < NGX_MAX_ERRLEN)

thibaultcha · 2024-11-21T19:50:33Z

src/common/proxy_wasm/ngx_proxy_wasm_foreign_callback.c

+}
+
+
+ngx_int_t


thibaultcha · 2024-11-21T19:57:15Z

src/common/proxy_wasm/ngx_proxy_wasm_host.c

+    ret_size = NGX_WAVM_HOST_LIFT(instance, args[5].of.i32, int32_t);
+
+    if (ngx_str_eq(fname.data, fname.len, "resolve_lua", -1)) {
+        return ngx_proxy_wasm_hfuncs_resolve_lua(instance, rctx, &fargs,


ngx_proxy_wasm_foreign_call_lua_resolve (?) -> foreign_call.c

thibaultcha · 2024-11-21T19:59:33Z

src/common/proxy_wasm/ngx_proxy_wasm_host.c

+
+    pwexec = ngx_proxy_wasm_instance2pwexec(instance);
+
+    cb = ngx_proxy_wasm_foreign_callback_alloc(pwexec);


thibaultcha · 2024-11-21T20:01:25Z

src/common/proxy_wasm/ngx_proxy_wasm_host.c

+        b = cb->args_out->buf;
+        s = *b->start;  /* first byte is the length of the resolved address */
+
+        p = ngx_proxy_wasm_alloc(pwexec, s);


catch bad alloc

thibaultcha · 2024-11-21T20:03:40Z

src/http/ngx_http_wasm_util.c

+
+
+ngx_int_t
+ngx_http_wasm_create_fake_req_ctx(ngx_proxy_wasm_exec_t *pwexec,


create_fake_rctx

thibaultcha · 2024-11-21T20:11:49Z

src/common/proxy_wasm/ngx_proxy_wasm_foreign_callback.h

+    ngx_queue_t                         q;
+    ngx_proxy_wasm_exec_t              *pwexec;
+#if (NGX_WASM_HTTP)
+    ngx_http_wasm_req_ctx_t            *rctx;


Suggested change

ngx_http_wasm_req_ctx_t *rctx;

thibaultcha · 2024-11-21T20:12:30Z

src/common/proxy_wasm/ngx_proxy_wasm_host.c

+
+          break;
+#endif
+


Suggested change

thibaultcha · 2024-11-21T20:16:45Z

src/common/proxy_wasm/ngx_proxy_wasm_host.c

+
+          *(p++) = sizeof(struct in6_addr);
+          p = ngx_cpymem(p, &sin6->sin6_addr, sizeof(struct in6_addr));
+


Suggested change

thibaultcha · 2024-11-21T20:18:48Z

src/common/proxy_wasm/ngx_proxy_wasm_host.c

+        p++;
+        goto not_found;
+    }
+


ngx_wa_assert(rslv_ctx->naddrs == 1) (perhaps?)

thibaultcha · 2024-11-21T20:19:05Z

src/common/proxy_wasm/ngx_proxy_wasm_host.c

+    ngx_wasm_socket_tcp_t        *sock;
+    ngx_proxy_wasm_exec_t        *pwexec;
+    ngx_proxy_wasm_foreign_cb_t  *cb;
+    ngx_wavm_ptr_t                p = 0;


Suggested change

ngx_wavm_ptr_t p = 0;

ngx_wavm_ptr_t p;

thibaultcha · 2024-11-21T20:19:29Z

src/common/proxy_wasm/ngx_proxy_wasm_host.c

+        cb->rctx = rctx;
+    }
+
+    sock = ngx_palloc(pwexec->pool, sizeof(ngx_wasm_socket_tcp_t));


Suggested change

sock = ngx_palloc(pwexec->pool, sizeof(ngx_wasm_socket_tcp_t));

sock = ngx_pcalloc(pwexec->pool, sizeof(ngx_wasm_socket_tcp_t));

thibaultcha · 2024-11-21T20:20:01Z

src/common/proxy_wasm/ngx_proxy_wasm_foreign_callback.c

+{
+    ngx_proxy_wasm_foreign_cb_t  *cb;
+
+    cb = ngx_palloc(pwexec->pool, sizeof(ngx_proxy_wasm_foreign_cb_t));


Suggested change

cb = ngx_palloc(pwexec->pool, sizeof(ngx_proxy_wasm_foreign_cb_t));

cb = ngx_pcalloc(pwexec->pool, sizeof(ngx_proxy_wasm_foreign_cb_t));

inlined

thibaultcha · 2024-11-21T20:20:36Z

src/common/proxy_wasm/ngx_proxy_wasm_host.c

+        goto error;
+    }
+
+    cb->fcode = NGX_PROXY_WASM_FOREIGN_RESOLVE;


Let's try with a function pointer when all those routiens move to "foreign_call.c"

thibaultcha · 2024-11-21T20:21:31Z

src/common/proxy_wasm/ngx_proxy_wasm_foreign_callback.c

+        b->last = ngx_cpymem(b->last, data->data, data->len);
+    }
+
+    /* TODO: data->len > b_size */


move up to the assert

misc(*) extract fake wasm_req_ctx into its own function

d42dee1

casimiro added the pr/work-in-progress PR: Work in progress label Nov 18, 2024

casimiro force-pushed the feat/wasm-foreign-function branch 5 times, most recently from d4b4267 to 99b8e75 Compare November 19, 2024 21:58

casimiro force-pushed the feat/wasm-foreign-function branch from 99b8e75 to 5bb49f5 Compare November 20, 2024 12:01

casimiro changed the title ~~feat(proxy-wasm) foreign function~~ feat(proxy-wasm) foreign function support Nov 20, 2024

casimiro force-pushed the feat/wasm-foreign-function branch 4 times, most recently from 7aa55fb to 08ec198 Compare November 21, 2024 13:11

wip

2ecb389

casimiro force-pushed the feat/wasm-foreign-function branch from 08ec198 to 2ecb389 Compare November 21, 2024 13:28

thibaultcha reviewed Nov 21, 2024

View reviewed changes

src/common/proxy_wasm/ngx_proxy_wasm.h

#endif

ngx_queue_t calls;

ngx_queue_t calls;

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dispatch_calls

thibaultcha reviewed Nov 21, 2024

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src/common/proxy_wasm/ngx_proxy_wasm_foreign_callback.c

}

ngx_int_t

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void

thibaultcha reviewed Nov 21, 2024

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src/http/ngx_http_wasm_util.c

ngx_int_t

ngx_http_wasm_create_fake_req_ctx(ngx_proxy_wasm_exec_t *pwexec,

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create_fake_rctx

thibaultcha reviewed Nov 21, 2024

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src/common/proxy_wasm/ngx_proxy_wasm_host.c

break;

#endif

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Suggested change

thibaultcha reviewed Nov 21, 2024

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src/common/proxy_wasm/ngx_proxy_wasm_host.c

p++;

goto not_found;

}

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ngx_wa_assert(rslv_ctx->naddrs == 1) (perhaps?)

thibaultcha reviewed Nov 21, 2024

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feat(proxy-wasm) foreign function support #626

feat(proxy-wasm) foreign function support #626

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		pwexec = ngx_proxy_wasm_instance2pwexec(instance);

		cb = ngx_proxy_wasm_foreign_callback_alloc(pwexec);



		ngx_int_t
		ngx_http_wasm_create_fake_req_ctx(ngx_proxy_wasm_exec_t *pwexec,


		*(p++) = sizeof(struct in6_addr);
		p = ngx_cpymem(p, &sin6->sin6_addr, sizeof(struct in6_addr));

	sock = ngx_palloc(pwexec->pool, sizeof(ngx_wasm_socket_tcp_t));
	sock = ngx_pcalloc(pwexec->pool, sizeof(ngx_wasm_socket_tcp_t));

	cb = ngx_palloc(pwexec->pool, sizeof(ngx_proxy_wasm_foreign_cb_t));
	cb = ngx_pcalloc(pwexec->pool, sizeof(ngx_proxy_wasm_foreign_cb_t));

feat(proxy-wasm) foreign function support #626

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casimiro commented Nov 18, 2024 • edited Loading

Foreign Function Support

DNS resolution

TODO

codecov bot commented Nov 19, 2024 • edited Loading

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