feat: add wasm-rust sdk with say-hello simple extension (#350)

plugins/wasm-rust/extensions/say-hello/src/lib.rs

@@ -0,0 +1,112 @@
+// Copyright (c) 2023 Alibaba Group Holding Ltd.
+//
+// Licensed 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 higress_wasm_rust::log::Log;
+use higress_wasm_rust::rule_matcher::RuleMatcher;
+use proxy_wasm::traits::{Context, HttpContext, RootContext};
+use proxy_wasm::types::{Action, ContextType, LogLevel};
+use serde::Deserialize;
+use serde_json::{from_slice, Value};
+use std::cell::RefCell;
+use std::rc::Rc;
+
+proxy_wasm::main! {{
+    proxy_wasm::set_log_level(LogLevel::Trace);
+    proxy_wasm::set_root_context(|_|Box::new(SayHelloRoot::new()));
+}}
+
+struct SayHelloRoot {
+    log: Log,
+    rule_matcher: Rc<RefCell<RuleMatcher<SayHelloConfig>>>,
+}
+
+struct SayHello {
+    rule_matcher: Rc<RefCell<RuleMatcher<SayHelloConfig>>>,
+}
+
+#[derive(Default, Debug, Deserialize)]
+struct SayHelloConfig {
+    name: String,
+}
+
+impl SayHelloRoot {
+    fn new() -> Self {
+        SayHelloRoot {
+            log: Log::new("say_hello".to_string()),
+            rule_matcher: Rc::new(RefCell::new(RuleMatcher::default())),
+        }
+    }
+}
+
+impl Context for SayHelloRoot {}
+
+impl RootContext for SayHelloRoot {
+    fn on_configure(&mut self, _plugin_configuration_size: usize) -> bool {
+        let config_buffer = match self.get_plugin_configuration() {
+            None => {
+                self.log
+                    .error("Error when configuring RootContext, no configuration supplied");
+                return false;
+            }
+            Some(bytes) => bytes,
+        };
+
+        let value = match from_slice::<Value>(config_buffer.as_slice()) {
+            Err(error) => {
+                self.log.error(
+                    format!("cannot parse plugin configuration JSON string: {}", error).as_str(),
+                );
+                return false;
+            }
+            Ok(value) => value,
+        };
+
+        self.rule_matcher
+            .borrow_mut()
+            .parse_rule_config(&value)
+            .is_ok()
+    }
+
+    fn create_http_context(&self, _context_id: u32) -> Option<Box<dyn HttpContext>> {
+        Some(Box::new(SayHello {
+            rule_matcher: self.rule_matcher.clone(),
+        }))
+    }
+
+    fn get_type(&self) -> Option<ContextType> {
+        Some(ContextType::HttpContext)
+    }
+}
+
+impl Context for SayHello {}
+
+impl HttpContext for SayHello {
+    fn on_http_request_headers(&mut self, _num_headers: usize, _end_of_stream: bool) -> Action {
+        let binding = self.rule_matcher.borrow();
+        let config = match binding.get_match_config() {
+            None => {
+                self.send_http_response(200, vec![], Some("Hello, World!".as_bytes()));
+                return Action::Continue;
+            }
+            Some(config) => config,
+        };
+
+        self.send_http_response(
+            200,
+            vec![],
+            Some(format!("Hello, {}!", config.name).as_bytes()),
+        );
+        Action::Continue
+    }
+}