Merge pull request 'Allow multiple backends' (#5) from feature/multiple-backends into master

Reviewed-on: #5

config.toml

@@ -5,3 +5,20 @@ threads = 1
 
 [runner]
 timeout = 2
+
+[runners.javascript]
+type = "bubblewrap"
+args = ["node", "-e", "{}"]
+
+[runners.bun]
+type = "bubblewrap"
+args = ["bun", "run", "/dev/stdin"]
+
+[runners.bash]
+type = "bubblewrap"
+args = ["bash", "-c", "{}"]
+
+[runners.moshell]
+type = "docker"
+image = "ghcr.io/moshell-lang/moshell:master"
+args = ["moshell", "-c", "{}"]

src/config.cpp

@@ -4,6 +4,48 @@
 #include <toml++/toml.h>
 
 static sk::config read(const toml::table &config) {
+    std::unordered_map<std::string, sk::runner_strategy_config> strategies;
+    auto *table = config["runners"].as_table();
+    if (table != nullptr) {
+        for (auto [name, backend_config] : *table) {
+            auto *backend_table = backend_config.as_table();
+            if (backend_table == nullptr) {
+                std::cerr << "Invalid runner config for " << name << ": expected table\n";
+                continue;
+            }
+            auto *backend_type = backend_table->get_as<std::string>("type");
+            if (backend_type == nullptr) {
+                std::cerr << "Invalid runner config for " << name << ": missing type field\n";
+                continue;
+            }
+            auto *args = backend_table->get_as<toml::array>("args");
+            if (args == nullptr) {
+                std::cerr << "Invalid runner config for " << name << ": missing args field\n";
+                continue;
+            }
+            std::vector<std::string> args_vector;
+            for (const auto &arg : *args) {
+                auto *arg_string = arg.as_string();
+                if (arg_string == nullptr) {
+                    std::cerr << "Invalid runner config for " << name << ": args must be strings\n";
+                    continue;
+                }
+                args_vector.emplace_back(*arg_string);
+            }
+            if (*backend_type == "docker") {
+                auto *image = backend_table->get_as<std::string>("image");
+                if (image == nullptr) {
+                    std::cerr << "Invalid runner config for " << name << ": missing image field\n";
+                    continue;
+                }
+                strategies.emplace(name, sk::docker_config{{std::move(args_vector)}, std::string{*image}});
+            } else if (*backend_type == "bubblewrap") {
+                strategies.emplace(name, sk::bubblewrap_config{std::move(args_vector)});
+            } else {
+                std::cerr << "Invalid runner config for " << name << ": unknown type " << *backend_type << "\n";
+            }
+        }
+    }
     return sk::config{
         sk::queue_config{
             config["queue"]["pull"].value_or("tcp://localhost:5557"),
@@ -12,6 +54,7 @@ static sk::config read(const toml::table &config) {
         },
         sk::runner_config{
             config["runner"]["timeout"].value_or(2u),
+            std::move(strategies),
         },
     };
 }

src/config.hpp

@@ -2,6 +2,9 @@
 
 #include <filesystem>
 #include <string>
+#include <unordered_map>
+#include <variant>
+#include <vector>
 
 namespace sk {
 struct queue_config {
@@ -10,8 +13,19 @@ struct queue_config {
     unsigned int nb_threads;
 };
 
+struct bubblewrap_config {
+    std::vector<std::string> args;
+};
+
+struct docker_config : bubblewrap_config {
+    std::string image;
+};
+
+using runner_strategy_config = std::variant<bubblewrap_config, docker_config>;
+
 struct runner_config {
     unsigned int timeout;
+    std::unordered_map<std::string, runner_strategy_config> strategies;
 };
 
 struct config {

src/main.cpp

@@ -36,7 +36,7 @@ sk::runner_backend detect_backend() {
     return sk::runner_backend::BubbleWrap;
 }
 
-sk::runner *global_runner = nullptr;
+sk::runner_list *global_runners = nullptr;
 
 int main(int argc, char **argv) {
     int opt;
@@ -62,12 +62,12 @@ int main(int argc, char **argv) {
     }
 
     sk::config config = sk::config::read_or_default(config_path, !may_use_default_config);
-    sk::runner runner(selected_backend.has_value() ? selected_backend.value() : detect_backend(), config.runner);
-    global_runner = &runner;
+    sk::runner_list runners(selected_backend.has_value() ? selected_backend.value() : detect_backend(), config.runner);
+    global_runners = &runners;
     struct sigaction action {};
     action.sa_handler = [](int) {
-        if (global_runner) {
-            global_runner->exit_active_jobs();
+        if (global_runners) {
+            global_runners->exit_active_jobs();
         }
     };
     sigaction(SIGINT, &action, nullptr);
@@ -82,8 +82,13 @@ int main(int argc, char **argv) {
         std::stringstream buffer;
         buffer << t.rdbuf();
         std::string code = buffer.str();
-        sk::program program{"sample-code", code, "ghcr.io/moshell-lang/moshell:master"};
-        sk::run_result result = runner.run_blocking(program);
+        sk::program program{"sample-code", code, "moshell"};
+        sk::runner *runner = runners.find_runner_for(program);
+        if (runner == nullptr) {
+            std::cerr << "No runner found for " << program.image << std::endl;
+            return 1;
+        }
+        sk::run_result result = runner->run_blocking(program);
         std::cout << "exited with: " << result.exit_code << "\n";
         std::cout << "out: " << result.out << "\n";
         std::cout << "err: " << result.err << "\n";
@@ -132,7 +137,16 @@ int main(int argc, char **argv) {
             std::cout << "Executing " << codeLen << " bytes code.\n";
 #endif
             sk::program program{std::move(jobId), std::move(requestString), std::move(imageString)};
-            sk::run_result result = runner.run_blocking(program);
+            sk::runner *runner = runners.find_runner_for(program);
+            if (runner == nullptr) {
+                send(STDERR_CLIENT_BOUND, program.name, "No runner found for " + program.image);
+                sk::prepare_headers(sizeof(uint32_t), EXIT_CLIENT_BOUND, program.name);
+                auto [reply, reply_bytes] = sk::prepare_headers(sizeof(uint32_t), EXIT_CLIENT_BOUND, program.name);
+                sk::write_uint32(reply_bytes, -1);
+                sender.send(reply, zmq::send_flags::none);
+                continue;
+            }
+            sk::run_result result = runner->run_blocking(program);
 
             if (!result.out.empty()) {
                 send(STDOUT_CLIENT_BOUND, program.name, result.out);
@@ -151,7 +165,7 @@ int main(int argc, char **argv) {
                 continue;
             }
             std::string jobId(message, sk::JOB_ID_LEN);
-            runner.kill_active(jobId);
+            runners.kill_active(jobId);
             break;
         }
         default:

src/runner.cpp

@@ -18,8 +18,102 @@ static auto ensure = [](int res) -> void {
     }
 };
 
+template <class> inline constexpr bool always_false_v = false;
+
 namespace sk {
-runner::runner(runner_backend backend, const runner_config &config) : backend{backend}, timeout{static_cast<int>(config.timeout)} {}
+execution_strategy::execution_strategy(const std::vector<std::string> &patterns) {
+    for (const auto &pattern : patterns) {
+        if (pattern == "{}") {
+            this->patterns.emplace_back(nullptr);
+        } else {
+            this->patterns.emplace_back(pattern);
+        }
+    }
+}
+
+execution_strategy::execution_strategy(std::vector<pattern> patterns) : patterns(std::move(patterns)) {}
+
+std::unique_ptr<execution_strategy> execution_strategy::create(const runner_strategy_config &config) {
+    return std::visit(
+        [](auto &&strategy) -> std::unique_ptr<execution_strategy> {
+            using T = std::decay_t<decltype(strategy)>;
+            if constexpr (std::is_same_v<T, sk::bubblewrap_config>) {
+                return std::make_unique<bubblewrap_execution_strategy>(strategy.args);
+            } else if constexpr (std::is_same_v<T, sk::docker_config>) {
+                return std::make_unique<docker_execution_strategy>(strategy.args, strategy.image);
+            } else {
+                static_assert(always_false_v<T>, "non-exhaustive visitor!");
+            }
+        },
+        config);
+}
+
+void execution_strategy::concat_patterns(std::vector<const char *> &args, const program &program) const {
+    for (const auto &pattern : patterns) {
+        std::visit(
+            [&args, &program](const auto &arg) {
+                if constexpr (std::is_same_v<std::string, std::decay_t<decltype(arg)>>) {
+                    args.push_back(arg.c_str());
+                } else {
+                    args.push_back(program.code.c_str());
+                }
+            },
+            pattern);
+    }
+}
+
+bubblewrap_execution_strategy::bubblewrap_execution_strategy(const std::vector<std::string> &patterns) : execution_strategy{patterns} {}
+
+bubblewrap_execution_strategy::bubblewrap_execution_strategy(std::vector<pattern> patterns) : execution_strategy{std::move(patterns)} {}
+
+std::vector<const char *> bubblewrap_execution_strategy::start(const program &program) {
+    std::vector<const char *> args{"bwrap", "--ro-bind", "/usr", "/usr", "--dir", "/tmp", "--dir", "/var", "--proc", "/proc", "--dev", "/dev", "--symlink", "usr/lib", "/lib", "--symlink", "usr/lib64", "/lib64", "--symlink", "usr/bin", "/bin", "--symlink", "usr/sbin", "/sbin", "--unshare-all", "--die-with-parent"};
+    concat_patterns(args, program);
+    return args;
+}
+
+void bubblewrap_execution_strategy::stop(const active_job &job) { ensure(kill(job.pid, SIGINT)); }
+
+docker_execution_strategy::docker_execution_strategy(const std::vector<std::string> &patterns, std::string image) : execution_strategy{patterns}, image{std::move(image)} {}
+
+docker_execution_strategy::docker_execution_strategy(std::vector<pattern> patterns, std::string image) : execution_strategy{std::move(patterns)}, image{std::move(image)} {}
+
+std::vector<const char *> docker_execution_strategy::start(const program &program) {
+    std::vector<const char *> args{"docker", "run", "--rm", "-i", "--name", program.name.c_str(), "--pull=never", "--cap-drop=ALL", "--network=none", "--memory=64m", "--memory-swap=64m", "--pids-limit=128", image.c_str()};
+    concat_patterns(args, program);
+    return args;
+}
+
+void docker_execution_strategy::stop(const active_job &job) {
+    const char *const kill_args[] = {"docker", "kill", job.job_id.c_str(), nullptr};
+    pid_t kill_pid;
+    ensure(posix_spawnp(&kill_pid, kill_args[0], nullptr, nullptr, const_cast<char *const *>(kill_args), nullptr));
+}
+
+runner::runner(const runner_strategy_config &config, unsigned int timeout) : backend{execution_strategy::create(config)}, timeout{static_cast<int>(timeout)} {}
+
+runner::runner(const runner &other) : backend{&*other.backend}, timeout{other.timeout} {}
+
+runner::runner(runner &&other) noexcept : backend{std::move(other.backend)}, timeout{other.timeout} {}
+
+runner &runner::operator=(const runner &other) {
+    if (this == &other) {
+        return *this;
+    }
+    std::unique_ptr<execution_strategy> new_backend(&*other.backend);
+    backend = std::move(new_backend);
+    timeout = other.timeout;
+    return *this;
+}
+
+runner &runner::operator=(runner &&other) noexcept {
+    if (this == &other) {
+        return *this;
+    }
+    backend = std::move(other.backend);
+    timeout = other.timeout;
+    return *this;
+}
 
 run_result runner::run_blocking(const program &program) {
     // Open file descriptors ahead of time
@@ -51,16 +145,12 @@ run_result runner::run_blocking(const program &program) {
     posix_spawn_file_actions_adddup2(&actions, in_pipe[0], STDIN_FILENO);
     posix_spawn_file_actions_adddup2(&actions, out_pipe[1], STDOUT_FILENO);
     posix_spawn_file_actions_adddup2(&actions, err_pipe[1], STDERR_FILENO);
-    const char *const docker_args[] = {"docker", "run", "--rm", "-i", "--name", program.name.c_str(), "--pull=never", "--cap-drop=ALL", "--network=none", "--memory=64m", "--memory-swap=64m", "--pids-limit=128", program.image.c_str(), nullptr};
-    const char *const bwrap_args[] = {"bwrap", "--ro-bind", "/usr", "/usr", "--dir", "/tmp", "--dir", "/var", "--proc", "/proc", "--dev", "/dev", "--symlink", "usr/lib", "/lib", "--symlink", "usr/lib64", "/lib64", "--symlink", "usr/bin", "/bin", "--symlink", "usr/sbin", "/sbin", "--unshare-all", "--die-with-parent", "/bin/sh", nullptr};
-    const char *const *args = docker_args;
-    if (backend == runner_backend::BubbleWrap) {
-        args = bwrap_args;
-    }
+    std::vector<const char *> args = backend->start(program);
+    args.push_back(nullptr);
     pid_t pid;
     bool killed = false;
     int exit_code;
-    if (posix_spawnp(&pid, args[0], &actions, nullptr, const_cast<char *const *>(args), nullptr) != 0) {
+    if (posix_spawnp(&pid, args[0], &actions, nullptr, const_cast<char *const *>(args.data()), nullptr) != 0) {
         throw std::system_error{errno, std::generic_category()};
     }
 
@@ -184,13 +274,29 @@ void runner::exit_active_jobs() {
     active_jobs.clear();
 }
 
-void runner::exit(const active_job &job) {
-    if (backend == runner_backend::Docker) {
-        const char *const kill_args[] = {"docker", "kill", job.job_id.c_str(), nullptr};
-        pid_t kill_pid;
-        ensure(posix_spawnp(&kill_pid, kill_args[0], nullptr, nullptr, const_cast<char *const *>(kill_args), nullptr));
-    } else {
-        ensure(kill(job.pid, SIGINT));
+void runner::exit(const active_job &job) { backend->stop(job); }
+
+runner_list::runner_list(sk::runner_backend preferred_backend, const runner_config &config) {
+    for (const auto &strategy : config.strategies) {
+        runners.emplace(std::string{strategy.first}, runner{strategy.second, config.timeout});
+    }
+}
+
+runner *runner_list::find_runner_for(const program &program) {
+    auto it = runners.find(program.image);
+    if (it != runners.end()) {
+        return &it->second;
+    }
+    return nullptr;
+}
+
+bool runner_list::kill_active(const std::string &jobId) {
+    return std::any_of(runners.begin(), runners.end(), [&jobId](auto &runner) { return runner.second.kill_active(jobId); });
+}
+
+void runner_list::exit_active_jobs() {
+    for (auto &[name, runner] : runners) {
+        runner.exit_active_jobs();
     }
 }
 }

src/runner.hpp

@@ -2,8 +2,10 @@
 
 #include "config.hpp"
 #include "program.hpp"
+#include <memory>
 #include <mutex>
 #include <string>
+#include <variant>
 #include <vector>
 
 namespace sk {
@@ -19,20 +21,67 @@ struct [[nodiscard]] active_job {
 };
 
 enum class runner_backend { BubbleWrap, Docker };
+using pattern = std::variant<std::string, void *>;
+
+class execution_strategy {
+    std::vector<pattern> patterns;
+
+  public:
+    explicit execution_strategy(const std::vector<std::string> &patterns);
+    explicit execution_strategy(std::vector<pattern> patterns);
+    virtual std::vector<const char *> start(const program &program) = 0;
+    virtual void stop(const active_job &job) = 0;
+    virtual ~execution_strategy() = default;
+    static std::unique_ptr<execution_strategy> create(const runner_strategy_config &config);
+
+  protected:
+    void concat_patterns(std::vector<const char *> &args, const program &program) const;
+};
+
+class bubblewrap_execution_strategy : public execution_strategy {
+  public:
+    explicit bubblewrap_execution_strategy(const std::vector<std::string> &patterns);
+    explicit bubblewrap_execution_strategy(std::vector<pattern> patterns);
+    std::vector<const char *> start(const program &program) override;
+    void stop(const active_job &job) override;
+};
+
+class docker_execution_strategy : public execution_strategy {
+  private:
+    std::string image;
+
+  public:
+    docker_execution_strategy(const std::vector<std::string> &patterns, std::string image);
+    docker_execution_strategy(std::vector<pattern> patterns, std::string image);
+    std::vector<const char *> start(const program &program) override;
+    void stop(const active_job &job) override;
+};
 
 class runner {
-    runner_backend backend;
-    int timeout;
     std::vector<active_job> active_jobs;
     std::mutex active_jobs_mutex;
+    std::unique_ptr<execution_strategy> backend;
+    int timeout;
 
   public:
-    runner(runner_backend backend, const runner_config &config);
+    explicit runner(const runner_strategy_config &config, unsigned int timeout = 2u);
+    runner(const runner &other);
+    runner(runner &&other) noexcept;
+    runner &operator=(const runner &other);
+    runner &operator=(runner &&other) noexcept;
     run_result run_blocking(const program &program);
     bool kill_active(const std::string &jobId);
     void exit_active_jobs();
-
-  private:
     void exit(const active_job &job);
 };
+
+class runner_list {
+    std::unordered_map<std::string, runner> runners;
+
+  public:
+    runner_list(sk::runner_backend preferred_backend, const runner_config &config);
+    runner *find_runner_for(const program &program);
+    bool kill_active(const std::string &jobId);
+    void exit_active_jobs();
+};
 }