feat: implement proxy_send_http_response (#15)

Author: spacewander

lib/resty/proxy-wasm.lua

@@ -1,6 +1,7 @@
 local ffi = require("ffi")
 local base = require("resty.core.base")
 local ffi_gc = ffi.gc
+local ffi_str = ffi.string
 local C = ffi.C
 local get_request = base.get_request
 
@@ -9,12 +10,19 @@ base.allows_subsystem("http")
 
 
 ffi.cdef[[
+typedef unsigned char u_char;
+typedef struct {
+    size_t      len;
+    u_char     *data;
+} ngx_str_t;
 typedef long ngx_int_t;
 void *ngx_http_wasm_load_plugin(const char *code, size_t size);
 void ngx_http_wasm_unload_plugin(void *plugin);
 void *ngx_http_wasm_on_configure(void *plugin, const char *conf, size_t size);
 void ngx_http_wasm_delete_plugin_ctx(void *hwp_ctx);
+
 ngx_int_t ngx_http_wasm_on_http(void *hwp_ctx, void *r, int type);
+ngx_str_t *ngx_http_wasm_fetch_local_body(void *r);
 ]]
 
 
@@ -77,6 +85,17 @@ function _M.on_http_request_headers(plugin_ctx)
         return nil, "failed to run proxy_on_http_request_headers"
     end
 
+    if rc >= 100 then
+        ngx.status = rc
+        local p = C.ngx_http_wasm_fetch_local_body(r)
+        if p ~= nil then
+            local body = ffi_str(p.data, p.len)
+            ngx.print(body)
+        end
+
+        ngx.exit(0)
+    end
+
     return true
 end
 

proxy_wasm_abi.md

@@ -156,3 +156,25 @@ because proxy-wasm-go-sdk uses it.
   - `i32 (size_t*) return_buffer_size`
 * returns:
   - `i32 (proxy_result_t) call_result`
+
+
+## HTTP (L7) extensions
+
+### `proxy_send_http_response`
+
+* params:
+  - `i32 (uint32_t) response_code`
+  - `i32 (const char*) response_code_details_data`
+  - `i32 (size_t) response_code_details_size`
+  - `i32 (const char*) response_body_data`
+  - `i32 (size_t) response_body_size`
+  - `i32 (const char*) additional_headers_map_data`
+  - `i32 (size_t) additional_headers_size`
+  - `i32 (uint32_t) grpc_status`
+* returns:
+  - `i32 (proxy_result_t) call_result`
+
+Sends HTTP response without forwarding request to the upstream.
+Note: we only implement the handling of response_code and response_body.
+
+We only implement `proxy_send_local_response` as an alias because proxy-wasm-go-sdk uses it.

src/http/ngx_http_wasm_api.c

@@ -1,5 +1,6 @@
 #include "vm/vm.h"
 #include "ngx_http_wasm_api.h"
+#include "ngx_http_wasm_module.h"
 #include "ngx_http_wasm_state.h"
 
 
@@ -157,3 +158,45 @@ proxy_get_buffer_bytes(int32_t type, int32_t start, int32_t length,
 
     return PROXY_RESULT_OK;
 }
+
+
+int32_t
+proxy_send_http_response(int32_t res_code,
+                         int32_t res_code_details_data, int32_t res_code_details_size,
+                         int32_t body, int32_t body_size,
+                         int32_t headers, int32_t headers_size,
+                         int32_t grpc_status)
+{
+    ngx_http_wasm_main_conf_t  *wmcf;
+    ngx_http_request_t         *r;
+    ngx_log_t                  *log;
+    const u_char               *p;
+
+    r = ngx_http_wasm_get_req();
+    if (r == NULL) {
+        return PROXY_RESULT_BAD_ARGUMENT;
+    }
+
+    log = r->connection->log;
+
+    wmcf = ngx_http_get_module_main_conf(r, ngx_http_wasm_module);
+    /* TODO handle other args */
+    wmcf->code = res_code;
+    wmcf->body.len = body_size;
+
+    if (body_size > 0) {
+        p = ngx_wasm_vm.get_memory(log, body, body_size);
+        if (p == NULL) {
+            return PROXY_RESULT_INVALID_MEMORY_ACCESS;
+        }
+
+        wmcf->body.data = ngx_palloc(r->pool, body_size);
+        if (wmcf->body.data == NULL) {
+            ngx_log_error(NGX_LOG_ERR, log, 0, "no memory");
+            return PROXY_RESULT_INTERNAL_FAILURE;
+        }
+        ngx_memcpy(wmcf->body.data, p, body_size);
+    }
+
+    return PROXY_RESULT_OK;
+}

src/http/ngx_http_wasm_api.h

@@ -8,7 +8,7 @@
 #include "ngx_http_wasm_types.h"
 
 
-#define MAX_WASM_API_ARG  5
+#define MAX_WASM_API_ARG  8
 
 
 #define DEFINE_WASM_API(NAME, ARG, ARG_CHECK) \
@@ -54,14 +54,34 @@
     int32_t p5 = args[4].of.i32; \
     int32_t res = NAME(p1, p2, p3, p4, p5);
 
+#define DEFINE_WASM_API_ARG_I32_I32_I32_I32_I32_I32_I32_I32 \
+    int32_t, int32_t, int32_t, int32_t, int32_t, int32_t, int32_t, int32_t
+
+#define DEFINE_WASM_API_ARG_CHECK_I32_I32_I32_I32_I32_I32_I32_I32(NAME) \
+    int32_t p1 = args[0].of.i32; \
+    int32_t p2 = args[1].of.i32; \
+    int32_t p3 = args[2].of.i32; \
+    int32_t p4 = args[3].of.i32; \
+    int32_t p5 = args[4].of.i32; \
+    int32_t p6 = args[5].of.i32; \
+    int32_t p7 = args[6].of.i32; \
+    int32_t p8 = args[7].of.i32; \
+    int32_t res = NAME(p1, p2, p3, p4, p5, p6, p7, p8);
+
+
 #define DEFINE_WASM_NAME(NAME, ARG) \
     {ngx_string(#NAME), wasmtime_##NAME, ARG},
+#define DEFINE_WASM_NAME_ALIAS(NAME, ARG, ALIAS) \
+    {ngx_string(#NAME), wasmtime_##NAME, ARG}, \
+    {ngx_string(#ALIAS), wasmtime_##NAME, ARG},
 #define DEFINE_WASM_NAME_ARG_I32 \
     1, {WASM_I32}
 #define DEFINE_WASM_NAME_ARG_I32_I32_I32 \
     3, {WASM_I32, WASM_I32, WASM_I32}
 #define DEFINE_WASM_NAME_ARG_I32_I32_I32_I32_I32 \
     5, {WASM_I32, WASM_I32, WASM_I32, WASM_I32, WASM_I32}
+#define DEFINE_WASM_NAME_ARG_I32_I32_I32_I32_I32_I32_I32_I32 \
+    8, {WASM_I32, WASM_I32, WASM_I32, WASM_I32, WASM_I32, WASM_I32, WASM_I32, WASM_I32}
 
 
 typedef struct {
@@ -81,12 +101,19 @@ DEFINE_WASM_API(proxy_log,
 DEFINE_WASM_API(proxy_get_buffer_bytes,
                 DEFINE_WASM_API_ARG_I32_I32_I32_I32_I32,
                 DEFINE_WASM_API_ARG_CHECK_I32_I32_I32_I32_I32(proxy_get_buffer_bytes))
+DEFINE_WASM_API(proxy_send_http_response,
+                DEFINE_WASM_API_ARG_I32_I32_I32_I32_I32_I32_I32_I32,
+                DEFINE_WASM_API_ARG_CHECK_I32_I32_I32_I32_I32_I32_I32_I32(
+                    proxy_send_http_response))
 
 
 static ngx_wasm_host_api_t host_apis[] = {
     DEFINE_WASM_NAME(proxy_set_effective_context, DEFINE_WASM_NAME_ARG_I32)
     DEFINE_WASM_NAME(proxy_log, DEFINE_WASM_NAME_ARG_I32_I32_I32)
     DEFINE_WASM_NAME(proxy_get_buffer_bytes, DEFINE_WASM_NAME_ARG_I32_I32_I32_I32_I32)
+    DEFINE_WASM_NAME_ALIAS(proxy_send_http_response,
+                           DEFINE_WASM_NAME_ARG_I32_I32_I32_I32_I32_I32_I32_I32,
+                           proxy_send_local_response)
     { ngx_null_string, NULL, 0, {} }
 };
 

src/http/ngx_http_wasm_module.c

@@ -1,6 +1,7 @@
 #include <ngx_config.h>
 #include <ngx_core.h>
 #include <ngx_http.h>
+#include "ngx_http_wasm_module.h"
 #include "ngx_http_wasm_state.h"
 #include "ngx_http_wasm_ctx.h"
 #include "vm/vm.h"
@@ -24,11 +25,6 @@ static ngx_str_t proxy_on_request_headers =
     ngx_string("proxy_on_request_headers");
 
 
-typedef struct {
-    ngx_str_t       vm;
-} ngx_http_wasm_main_conf_t;
-
-
 typedef enum {
     HTTP_REQUEST_HEADERS = 1,
 } ngx_http_wasm_phase_t;
@@ -89,6 +85,8 @@ ngx_http_wasm_create_main_conf(ngx_conf_t *cf)
 
     /* set by ngx_pcalloc:
      *      wmcf->vm = { 0, NULL };
+     *      wmcf->code = 0;
+     *      wmcf->body = { 0, NULL };
      */
 
     return wmcf;
@@ -561,6 +559,7 @@ ngx_http_wasm_on_http(ngx_http_wasm_plugin_ctx_t *hwp_ctx, ngx_http_request_t *r
     ngx_int_t                        rc;
     ngx_log_t                       *log;
     ngx_http_wasm_http_ctx_t        *http_ctx;
+    ngx_http_wasm_main_conf_t       *wmcf;
 
     log = r->connection->log;
 
@@ -569,6 +568,7 @@ ngx_http_wasm_on_http(ngx_http_wasm_plugin_ctx_t *hwp_ctx, ngx_http_request_t *r
         return NGX_DECLINED;
     }
 
+    wmcf = ngx_http_get_module_main_conf(r, ngx_http_wasm_module);
     hwp_ctx->state->r = r;
     ngx_http_wasm_set_state(hwp_ctx->state);
 
@@ -583,5 +583,37 @@ ngx_http_wasm_on_http(ngx_http_wasm_plugin_ctx_t *hwp_ctx, ngx_http_request_t *r
                           true, NGX_WASM_PARAM_I32_I32_I32, http_ctx->id,
                           0, 1);
     ngx_http_wasm_set_state(NULL);
+
+    if (rc < 0) {
+        return rc;
+    }
+
+    if (wmcf->code >= 100) {
+        int32_t code = wmcf->code;
+
+        /* reset code for next use */
+        wmcf->code = 0;
+
+        /* Return given http response instead of reaching the upstream.
+         * The body will be fetched later by ngx_http_wasm_fetch_local_body
+         * */
+        return code;
+    }
+
     return rc;
 }
+
+
+ngx_str_t *
+ngx_http_wasm_fetch_local_body(ngx_http_request_t *r)
+{
+    ngx_http_wasm_main_conf_t       *wmcf;
+
+    /* call after ngx_http_wasm_on_http */
+
+    wmcf = ngx_http_get_module_main_conf(r, ngx_http_wasm_module);
+    if (wmcf->body.len) {
+        return &wmcf->body;
+    }
+    return NULL;
+}

src/http/ngx_http_wasm_module.h

@@ -0,0 +1,18 @@
+#ifndef NGX_HTTP_WASM_MODULE_H
+#define NGX_HTTP_WASM_MODULE_H
+
+
+#include <ngx_core.h>
+
+
+typedef struct {
+    ngx_str_t       vm;
+    uint32_t        code;
+    ngx_str_t       body;
+} ngx_http_wasm_main_conf_t;
+
+
+extern ngx_module_t ngx_http_wasm_module;
+
+
+#endif // NGX_HTTP_WASM_MODULE_H

t/http_send_response.t

@@ -0,0 +1,34 @@
+use t::WASM 'no_plan';
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: sanity
+--- config
+location /t {
+    content_by_lua_block {
+        local wasm = require("resty.proxy-wasm")
+        local plugin = assert(wasm.load("t/testdata/http_send_response/main.go.wasm"))
+        local ctx = assert(wasm.on_configure(plugin, '403_body'))
+        assert(wasm.on_http_request_headers(ctx))
+    }
+}
+--- error_code: 403
+--- response_body chomp
+should not pass
+
+
+
+=== TEST 2: without body
+--- config
+location /t {
+    content_by_lua_block {
+        local wasm = require("resty.proxy-wasm")
+        local plugin = assert(wasm.load("t/testdata/http_send_response/main.go.wasm"))
+        local ctx = assert(wasm.on_configure(plugin, '502'))
+        assert(wasm.on_http_request_headers(ctx))
+    }
+}
+--- error_code: 502
+--- response_body chomp

t/testdata/http_send_response/main.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm"
+	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm/types"
+)
+
+func main() {
+	proxywasm.SetVMContext(&vmContext{})
+}
+
+type vmContext struct {
+	// Embed the default VM context here,
+	// so that we don't need to reimplement all the methods.
+	types.DefaultVMContext
+}
+
+// Override types.DefaultVMContext.
+func (*vmContext) NewPluginContext(contextID uint32) types.PluginContext {
+	return &pluginContext{}
+}
+
+type pluginContext struct {
+	// Embed the default plugin context here,
+	// so that we don't need to reimplement all the methods.
+	types.DefaultPluginContext
+}
+
+// Override types.DefaultPluginContext.
+func (*pluginContext) NewHttpContext(contextID uint32) types.HttpContext {
+	return &httpContext{contextID: contextID}
+}
+
+type httpContext struct {
+	// Embed the default http context here,
+	// so that we don't need to reimplement all the methods.
+	types.DefaultHttpContext
+	contextID uint32
+}
+
+// Override types.DefaultHttpContext.
+func (ctx *httpContext) OnHttpRequestHeaders(numHeaders int, endOfStream bool) types.Action {
+	data, err := proxywasm.GetPluginConfiguration()
+	if err != nil {
+		proxywasm.LogCriticalf("error reading plugin configuration: %v", err)
+		return types.ActionContinue
+	}
+
+	action := string(data)
+
+	if action == "403_body" {
+		body := "should not pass"
+		err = proxywasm.SendHttpResponse(403, [][2]string{
+			{"powered-by", "proxy-wasm-go-sdk!!"},
+		}, []byte(body), -1)
+	} else if action == "502" {
+		err = proxywasm.SendHttpResponse(502, nil, nil, -1)
+	}
+
+	if err != nil {
+		proxywasm.LogErrorf("failed to send local response: %v", err)
+		return types.ActionContinue
+	}
+	return types.ActionPause
+}