feat(wasm): run in http header_filter

apisix/wasm.lua

@@ -65,7 +65,7 @@ end
 local function access_wrapper(self, conf, ctx)
     local plugin_ctx, err = fetch_plugin_ctx(conf, ctx, self.plugin)
     if not plugin_ctx then
-        core.log.error("failed to init wasm plugin ctx: ", err)
+        core.log.error("failed to fetch wasm plugin ctx: ", err)
         return 503
     end
 
@@ -77,6 +77,21 @@ local function access_wrapper(self, conf, ctx)
 end
 
 
+local function header_filter_wrapper(self, conf, ctx)
+    local plugin_ctx, err = fetch_plugin_ctx(conf, ctx, self.plugin)
+    if not plugin_ctx then
+        core.log.error("failed to fetch wasm plugin ctx: ", err)
+        return 503
+    end
+
+    local ok, err = wasm.on_http_response_headers(plugin_ctx)
+    if not ok then
+        core.log.error("failed to run wasm plugin: ", err)
+        return 503
+    end
+end
+
+
 function _M.require(attrs)
     if not support_wasm then
         return nil, "need to build APISIX-OpenResty to support wasm"
@@ -101,6 +116,9 @@ function _M.require(attrs)
     mod.access = function (conf, ctx)
         return access_wrapper(mod, conf, ctx)
     end
+    mod.header_filter = function (conf, ctx)
+        return header_filter_wrapper(mod, conf, ctx)
+    end
 
     -- the returned values need to be the same as the Lua's 'require'
     return true, mod

docs/en/latest/wasm.md

@@ -93,4 +93,11 @@ Attributes below can be configured in the plugin:
 
 | Name           | Type                 | Requirement | Default        | Valid                                                                      | Description                                                                                                                                         |
 | --------------------------------------| ------------| -------------- | -------- | --------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------- |
-|  conf         | string | required |   |  != ""        | the plugin ctx configuration which can be fetched via Proxy WASM SDK |
+|  conf         | string | required |   |  != ""      | the plugin ctx configuration which can be fetched via Proxy WASM SDK |
+
+Here is the mapping between Proxy WASM callbacks and APISIX's phases:
+
+* `proxy_on_configure`: run once there is not PluginContext for the new configuration.
+For example, when the first request hits the route which has WASM plugin configured.
+* `proxy_on_http_request_headers`: run in the access phase.
+* `proxy_on_http_response_headers`: run in the header_filter phase.

t/wasm/response-rewrite.t

@@ -0,0 +1,94 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+use t::APISIX;
+
+my $nginx_binary = $ENV{'TEST_NGINX_BINARY'} || 'nginx';
+my $version = eval { `$nginx_binary -V 2>&1` };
+
+if ($version !~ m/\/apisix-nginx-module/) {
+    plan(skip_all => "apisix-nginx-module not installed");
+} else {
+    plan('no_plan');
+}
+
+add_block_preprocessor(sub {
+    my ($block) = @_;
+
+    if ((!defined $block->error_log) && (!defined $block->no_error_log)) {
+        $block->set_value("no_error_log", "[error]");
+    }
+
+    if (!defined $block->request) {
+        $block->set_value("request", "GET /t");
+    }
+
+    my $extra_yaml_config = <<_EOC_;
+wasm:
+    plugins:
+        - name: wasm-response-rewrite
+          priority: 7997
+          file: t/wasm/response-rewrite/main.go.wasm
+_EOC_
+    $block->set_value("extra_yaml_config", $extra_yaml_config);
+});
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: response rewrite headers
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/routes/1',
+                ngx.HTTP_PUT,
+                [[{
+                    "uri": "/hello",
+                    "upstream": {
+                        "type": "roundrobin",
+                        "nodes": {
+                            "127.0.0.1:1980": 1
+                        }
+                    },
+                    "plugins": {
+                        "wasm-response-rewrite": {
+                            "conf": "{\"headers\":[{\"name\":\"x-wasm\",\"value\":\"apisix\"}]}"
+                        }
+                    }
+                }]]
+            )
+
+            if code >= 300 then
+                ngx.status = code
+                ngx.say(body)
+                return
+            end
+
+            ngx.say(body)
+        }
+    }
+--- response_body
+passed
+
+
+
+=== TEST 2: hit
+--- request
+GET /hello
+--- response_headers
+x-wasm: apisix

t/wasm/response-rewrite/main.go

@@ -0,0 +1,89 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm"
+	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm/types"
+
+	"github.com/valyala/fastjson"
+)
+
+func main() {
+	proxywasm.SetVMContext(&vmContext{})
+}
+
+type vmContext struct {
+	types.DefaultVMContext
+}
+
+func (*vmContext) NewPluginContext(contextID uint32) types.PluginContext {
+	return &pluginContext{}
+}
+
+type header struct {
+	Name  string
+	Value string
+}
+
+type pluginContext struct {
+	types.DefaultPluginContext
+	Headers []header
+}
+
+func (ctx *pluginContext) OnPluginStart(pluginConfigurationSize int) types.OnPluginStartStatus {
+	data, err := proxywasm.GetPluginConfiguration()
+	if err != nil {
+		proxywasm.LogErrorf("error reading plugin configuration: %v", err)
+		return types.OnPluginStartStatusFailed
+	}
+
+	var p fastjson.Parser
+	v, err := p.ParseBytes(data)
+	if err != nil {
+		proxywasm.LogErrorf("erorr decoding plugin configuration: %v", err)
+		return types.OnPluginStartStatusFailed
+	}
+	headers := v.GetArray("headers")
+	ctx.Headers = make([]header, len(headers))
+	for i, hdr := range headers {
+		ctx.Headers[i] = header{
+			Name:  string(hdr.GetStringBytes("name")),
+			Value: string(hdr.GetStringBytes("value")),
+		}
+	}
+
+	return types.OnPluginStartStatusOK
+}
+
+func (ctx *pluginContext) NewHttpContext(contextID uint32) types.HttpContext {
+	return &httpContext{parent: ctx}
+}
+
+type httpContext struct {
+	types.DefaultHttpContext
+	parent *pluginContext
+}
+
+func (ctx *httpContext) OnHttpResponseHeaders(numHeaders int, endOfStream bool) types.Action {
+	plugin := ctx.parent
+	for _, hdr := range plugin.Headers {
+		proxywasm.ReplaceHttpResponseHeader(hdr.Name, hdr.Value)
+	}
+	return types.ActionContinue
+}