Add Jinja template support (#11016)

* Copy minja from 58f0ca6dd7

* Add --jinja and --chat-template-file flags

* Add missing <optional> include

* Avoid print in get_hf_chat_template.py

* No designated initializers yet

* Try and work around msvc++ non-macro max resolution quirk

* Update test_chat_completion.py

* Wire LLM_KV_TOKENIZER_CHAT_TEMPLATE_N in llama_model_chat_template

* Refactor test-chat-template

* Test templates w/ minja

* Fix deprecation

* Add --jinja to llama-run

* Update common_chat_format_example to use minja template wrapper

* Test chat_template in e2e test

* Update utils.py

* Update test_chat_completion.py

* Update run.cpp

* Update arg.cpp

* Refactor common_chat_* functions to accept minja template + use_jinja option

* Attempt to fix linkage of LLAMA_CHATML_TEMPLATE

* Revert LLAMA_CHATML_TEMPLATE refactor

* Normalize newlines in test-chat-templates for windows tests

* Forward decl minja::chat_template to avoid eager json dep

* Flush stdout in chat template before potential crash

* Fix copy elision warning

* Rm unused optional include

* Add missing optional include to server.cpp

* Disable jinja test that has a cryptic windows failure

* minja: fix vigogne (https://github.com/google/minja/pull/22)

* Apply suggestions from code review

Co-authored-by: Xuan Son Nguyen <thichthat@gmail.com>
Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

* Finish suggested renamings

* Move chat_templates inside server_context + remove mutex

* Update --chat-template-file w/ recent change to --chat-template

* Refactor chat template validation

* Guard against missing eos/bos tokens (null token otherwise throws in llama_vocab::impl::token_get_attr)

* Warn against missing eos / bos tokens when jinja template references them

* rename: common_chat_template[s]

* reinstate assert on chat_templates.template_default

* Update minja to b8437df626

* Update minja to https://github.com/google/minja/pull/25

* Update minja from https://github.com/google/minja/pull/27

* rm unused optional header

---------

Co-authored-by: Xuan Son Nguyen <thichthat@gmail.com>
Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

common/CMakeLists.txt

@@ -56,6 +56,7 @@ add_library(${TARGET} STATIC
     arg.cpp
     arg.h
     base64.hpp
+    chat-template.hpp
     common.cpp
     common.h
     console.cpp
@@ -64,6 +65,7 @@ add_library(${TARGET} STATIC
     json.hpp
     log.cpp
     log.h
+    minja.hpp
     ngram-cache.cpp
     ngram-cache.h
     sampling.cpp

common/arg.cpp

@@ -325,6 +325,14 @@ static bool common_params_parse_ex(int argc, char ** argv, common_params_context
         throw std::invalid_argument("error: either --embedding or --reranking can be specified, but not both");
     }
 
+    if (!params.chat_template.empty() && !common_chat_verify_template(params.chat_template, params.use_jinja)) {
+        throw std::runtime_error(string_format(
+            "error: the supplied chat template is not supported: %s%s\n",
+            params.chat_template.c_str(),
+            params.use_jinja ? "" : "\nnote: llama.cpp was started without --jinja, we only support commonly used templates"
+        ));
+    }
+
     return true;
 }
 
@@ -1947,24 +1955,44 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
             }
         }
     ).set_examples({LLAMA_EXAMPLE_SERVER}));
+    add_opt(common_arg(
+        {"--jinja"},
+        "use jinja template for chat (default: disabled)",
+        [](common_params & params) {
+            params.use_jinja = true;
+        }
+    ).set_examples({LLAMA_EXAMPLE_SERVER, LLAMA_EXAMPLE_MAIN}).set_env("LLAMA_ARG_JINJA"));
     add_opt(common_arg(
         {"--chat-template"}, "JINJA_TEMPLATE",
         string_format(
             "set custom jinja chat template (default: template taken from model's metadata)\n"
             "if suffix/prefix are specified, template will be disabled\n"
+            "only commonly used templates are accepted (unless --jinja is set before this flag):\n"
             "list of built-in templates:\n%s", list_builtin_chat_templates().c_str()
         ),
         [](common_params & params, const std::string & value) {
-            if (!common_chat_verify_template(value)) {
-                throw std::runtime_error(string_format(
-                    "error: the supplied chat template is not supported: %s\n"
-                    "note: llama.cpp does not use jinja parser, we only support commonly used templates\n",
-                    value.c_str()
-                ));
-            }
             params.chat_template = value;
         }
     ).set_examples({LLAMA_EXAMPLE_MAIN, LLAMA_EXAMPLE_SERVER}).set_env("LLAMA_ARG_CHAT_TEMPLATE"));
+    add_opt(common_arg(
+        {"--chat-template-file"}, "JINJA_TEMPLATE_FILE",
+        string_format(
+            "set custom jinja chat template file (default: template taken from model's metadata)\n"
+            "if suffix/prefix are specified, template will be disabled\n"
+            "only commonly used templates are accepted (unless --jinja is set before this flag):\n"
+            "list of built-in templates:\n%s", list_builtin_chat_templates().c_str()
+        ),
+        [](common_params & params, const std::string & value) {
+            std::ifstream file(value);
+            if (!file) {
+                throw std::runtime_error(string_format("error: failed to open file '%s'\n", value.c_str()));
+            }
+            std::copy(
+                std::istreambuf_iterator<char>(file),
+                std::istreambuf_iterator<char>(),
+                std::back_inserter(params.chat_template));
+        }
+    ).set_examples({LLAMA_EXAMPLE_MAIN, LLAMA_EXAMPLE_SERVER}).set_env("LLAMA_ARG_CHAT_TEMPLATE_FILE"));
     add_opt(common_arg(
         {"-sps", "--slot-prompt-similarity"}, "SIMILARITY",
         string_format("how much the prompt of a request must match the prompt of a slot in order to use that slot (default: %.2f, 0.0 = disabled)\n", params.slot_prompt_similarity),

common/chat-template.hpp

@@ -0,0 +1,249 @@
+/*
+    Copyright 2024 Google LLC
+
+    Use of this source code is governed by an MIT-style
+    license that can be found in the LICENSE file or at
+    https://opensource.org/licenses/MIT.
+*/
+// SPDX-License-Identifier: MIT
+#pragma once
+
+#include "minja.hpp"
+#include <json.hpp>
+#include <string>
+#include <vector>
+
+using json = nlohmann::ordered_json;
+
+namespace minja {
+
+class chat_template {
+  public:
+
+  private:
+    bool supports_tools_ = true;
+    // Meta-Llama-3.1-8B-Instruct's template expects arguments to be an object.
+    // Most other templates (and OpenAI's API) expect the arguments object to be stringified.
+    bool requires_object_arguments_ = false;
+    bool supports_system_role_ = true;
+    bool supports_parallel_tool_calls_ = false;
+    std::string source_;
+    std::string bos_token_;
+    std::string eos_token_;
+    std::shared_ptr<minja::TemplateNode> template_root_;
+
+    std::string try_render(
+        const nlohmann::ordered_json & messages,
+        const nlohmann::ordered_json & tools,
+        bool add_generation_prompt,
+        const nlohmann::ordered_json & extra_context = nlohmann::ordered_json()) const
+    {
+        try {
+            auto prompt = apply(messages, tools, add_generation_prompt, extra_context);
+            // fprintf(stderr, "Prompt: %s\n", prompt.c_str());
+            return prompt;
+        } catch (const std::exception & e) {
+            // fprintf(stderr, "Error: %s\n", e.what());
+            return "";
+        }
+    }
+
+  public:
+    chat_template(const std::string & source, const std::string & bos_token, const std::string & eos_token)
+        : source_(source), bos_token_(bos_token), eos_token_(eos_token)
+    {
+        template_root_ = minja::Parser::parse(source_, {
+            /* .trim_blocks = */ true,
+            /* .lstrip_blocks = */ true,
+            /* .keep_trailing_newline = */ false,
+        });
+        supports_tools_ = source.find("tools") != std::string::npos;
+
+        auto renders_string_arguments =
+            try_render({
+                {
+                    {"role", "user"},
+                    {"content", "Hey"}
+                },
+                {
+                    {"role", "assistant"},
+                    {"tool_calls", json::array({
+                        {
+                            {"id", "call_1___"},
+                            {"type", "function"},
+                            {"function", {
+                                {"arguments", "{\"code\": \"print('Hello, World!')\"}"},
+                                {"name", "ipython"},
+                            }},
+                        },
+                    })},
+                }
+            }, {}, false).find("{\"code\": \"print") != std::string::npos;
+        if (!renders_string_arguments) {
+            auto renders_object_arguments =
+                try_render({
+                    {
+                        {"role", "user"},
+                        {"content", "Hey"}
+                    },
+                    {
+                        {"role", "assistant"},
+                        {"tool_calls", json::array({
+                            {
+                                {"id", "call_1___"},
+                                {"type", "function"},
+                                {"function", {
+                                    {"arguments", {
+                                        {"code", "print('Hello, World!')"},
+                                    }},
+                                    {"name", "ipython"},
+                                }},
+                            },
+                        })},
+                    }
+                }, {}, false).find("{\"code\": \"print") != std::string::npos;
+            requires_object_arguments_ = renders_object_arguments;
+        }
+        supports_parallel_tool_calls_ = source.find("tool_call_id") != std::string::npos;
+
+        supports_system_role_ = try_render({
+            {{"role", "system"}, {"content", "<System Needle>"}},
+            {{"role", "user"},   {"content", "Hey"}}
+        }, {}, false).find("<System Needle>") != std::string::npos;
+    }
+
+    const std::string & source() const { return source_; }
+    const std::string & bos_token() const { return bos_token_; }
+    const std::string & eos_token() const { return eos_token_; }
+    bool supports_tools() const { return supports_tools_; }
+    bool supports_parallel_tool_calls() const { return supports_parallel_tool_calls_; }
+
+    std::string apply(
+        const nlohmann::ordered_json & messages,
+        const nlohmann::ordered_json & tools,
+        bool add_generation_prompt,
+        const nlohmann::ordered_json & extra_context = nlohmann::ordered_json()) const
+    {
+        json actual_messages;
+
+        // First, "fix" messages so they have a chance to be rendered correctly by the template
+
+        if (requires_object_arguments_ || !supports_system_role_ || !supports_tools_) {
+            actual_messages = json::array();
+
+            std::string pending_system;
+            auto flush_sys = [&]() {
+                if (!pending_system.empty()) {
+                    actual_messages.push_back({
+                        {"role", "user"},
+                        {"content", pending_system},
+                    });
+                    pending_system.clear();
+                }
+            };
+            for (const auto & message_ : messages) {
+                auto message = message_;
+                if (!message.contains("role") || !message.contains("content")) {
+                    throw std::runtime_error("message must have 'role' and 'content' fields: " + message.dump());
+                }
+                std::string role = message.at("role");
+
+                if (message.contains("tool_calls")) {
+                    if (requires_object_arguments_ || !supports_tools_) {
+                        for (auto & tool_call : message.at("tool_calls")) {
+                            if (tool_call["type"] == "function") {
+                                auto & function = tool_call.at("function");
+                                std::string arguments = function.at("arguments");
+                                function["arguments"] = json::parse(arguments);
+                            }
+                        }
+                    }
+                    if (!supports_tools_) {
+                        auto content = message.at("content");
+                        auto tool_calls = json::array();
+                        for (const auto & tool_call : message.at("tool_calls")) {
+                            if (tool_call.at("type") != "function") {
+                                continue;
+                            }
+                            const auto & function = tool_call.at("function");
+                            auto tc = json {
+                                {"name", function.at("name")},
+                                {"arguments", function.at("arguments")},
+                            };
+                            if (tool_call.contains("id")) {
+                                tc["id"] = tool_call["id"];
+                            }
+                            tool_calls.push_back(tc);
+                        }
+                        auto obj = json {
+                            {"tool_calls", tool_calls},
+                        };
+                        if (!content.is_null() && content != "") {
+                            obj["content"] = content;
+                        }
+                        message["content"] = obj.dump(2);
+                        message.erase("tool_calls");
+                    }
+                }
+                if (!supports_tools_ && role == "tool") {
+                    message["role"] = "user";
+                    auto obj = json {
+                        {"tool_response", {
+                            {"tool", message.at("name")},
+                            {"content", message.at("content")},
+                        }},
+                    };
+                    if (message.contains("tool_call_id")) {
+                        obj["tool_response"]["tool_call_id"] = message.at("tool_call_id");
+                    }
+                    message["content"] = obj.dump(2);
+                    message.erase("name");
+                }
+
+                if (!message["content"].is_null() && !supports_system_role_) {
+                    std::string content = message.at("content");
+                    if (role == "system") {
+                        if (!pending_system.empty()) pending_system += "\n";
+                        pending_system += content;
+                        continue;
+                    } else {
+                        if (role == "user") {
+                            if (!pending_system.empty()) {
+                                message["content"] = pending_system + (content.empty() ? "" : "\n" + content);
+                                pending_system.clear();
+                            }
+                        } else {
+                            flush_sys();
+                        }
+                    }
+                }
+                actual_messages.push_back(message);
+            }
+            flush_sys();
+        } else {
+            actual_messages = messages;
+        }
+
+        auto context = minja::Context::make(json({
+            {"messages", actual_messages},
+            {"add_generation_prompt", add_generation_prompt},
+            {"bos_token", bos_token_},
+            {"eos_token", eos_token_},
+        }));
+
+        if (!tools.is_null()) {
+            auto tools_val = minja::Value(tools);
+            context->set("tools", tools_val);
+        }
+        if (!extra_context.is_null()) {
+            for (auto & kv : extra_context.items()) {
+                minja::Value val(kv.value());
+                context->set(kv.key(), val);
+            }
+        }
+
+        return template_root_->render(context);
+    }
+};
+
+}  // namespace minja

common/common.cpp

@@ -12,6 +12,7 @@
 #include "json.hpp"
 #include "json-schema-to-grammar.h"
 #include "llama.h"
+#include "chat-template.hpp"
 
 #include <algorithm>
 #include <cinttypes>
@@ -1728,67 +1729,75 @@ std::string common_detokenize(const struct llama_vocab * vocab, const std::vecto
 // Chat template utils
 //
 
-std::string common_get_builtin_chat_template(const struct llama_model * model) {
-    const char * ptr_tmpl = llama_model_chat_template(model);
-    return ptr_tmpl == nullptr ? "" : ptr_tmpl;
-}
-
-bool common_chat_verify_template(const std::string & tmpl) {
+bool common_chat_verify_template(const std::string & tmpl, bool use_jinja) {
+    if (use_jinja) {
+        try {
+            auto chat_template = minja::chat_template(tmpl, "<s>", "</s>");
+            chat_template.apply({{
+                {"role", "user"},
+                {"content", "test"},
+            }}, json(), true);
+            return true;
+        } catch (const std::exception & e) {
+            LOG_ERR("%s: failed to apply template: %s\n", __func__, e.what());
+            return false;
+        }
+    }
     llama_chat_message chat[] = {{"user", "test"}};
     const int res = llama_chat_apply_template(tmpl.c_str(), chat, 1, true, nullptr, 0);
     return res >= 0;
 }
 
-std::string common_chat_apply_template(const struct llama_model * model,
-        const std::string & tmpl,
+std::string common_chat_apply_template(
+        const common_chat_template & tmpl,
         const std::vector<common_chat_msg> & msgs,
-        bool add_ass) {
+        bool add_ass,
+        bool use_jinja) {
+    if (use_jinja) {
+        auto messages = json::array();
+        for (const auto & msg : msgs) {
+            messages.push_back({{"role", msg.role}, {"content", msg.content}});
+        }
+        return tmpl.apply(messages, /* tools= */ json(), add_ass);
+    }
+
     int alloc_size = 0;
-    bool fallback = false; // indicate if we must fallback to default chatml
     std::vector<llama_chat_message> chat;
     for (const auto & msg : msgs) {
         chat.push_back({msg.role.c_str(), msg.content.c_str()});
         alloc_size += (msg.role.size() + msg.content.size()) * 1.25;
     }
 
-    const char * ptr_tmpl = tmpl.empty() ? llama_model_chat_template(model) : tmpl.c_str();
     std::vector<char> buf(alloc_size);
 
     // run the first time to get the total output length
-    int32_t res = llama_chat_apply_template(ptr_tmpl, chat.data(), chat.size(), add_ass, buf.data(), buf.size());
+    int32_t res = llama_chat_apply_template(tmpl.source().c_str(), chat.data(), chat.size(), add_ass, buf.data(), buf.size());
 
     // error: chat template is not supported
     if (res < 0) {
-        if (ptr_tmpl != nullptr) {
-            // if the custom "tmpl" is not supported, we throw an error
-            // this is a bit redundant (for good), since we're not sure if user validated the custom template with llama_chat_verify_template()
-            throw std::runtime_error("this custom template is not supported");
-        }
-
-        // If the built-in template is not supported, we default to chatml
-        res = llama_chat_apply_template("chatml", chat.data(), chat.size(), add_ass, buf.data(), buf.size());
-        fallback = true;
+        // if the custom "tmpl" is not supported, we throw an error
+        // this is a bit redundant (for good), since we're not sure if user validated the custom template with llama_chat_verify_template()
+        throw std::runtime_error("this custom template is not supported");
     }
 
     // if it turns out that our buffer is too small, we resize it
     if ((size_t) res > buf.size()) {
         buf.resize(res);
-        res = llama_chat_apply_template(
-            fallback ? "chatml" : ptr_tmpl,
-            chat.data(), chat.size(), add_ass, buf.data(), buf.size());
+        res = llama_chat_apply_template(tmpl.source().c_str(), chat.data(), chat.size(), add_ass, buf.data(), buf.size());
     }
 
     std::string formatted_chat(buf.data(), res);
     return formatted_chat;
 }
 
-std::string common_chat_format_single(const struct llama_model * model,
-        const std::string & tmpl,
+std::string common_chat_format_single(
+        const common_chat_template & tmpl,
         const std::vector<common_chat_msg> & past_msg,
         const common_chat_msg & new_msg,
-        bool add_ass) {
+        bool add_ass,
+        bool use_jinja) {
     std::ostringstream ss;
-    auto fmt_past_msg = past_msg.empty() ? "" : common_chat_apply_template(model, tmpl, past_msg, false);
+    auto fmt_past_msg = past_msg.empty() ? "" : common_chat_apply_template(tmpl, past_msg, false, use_jinja);
     std::vector<common_chat_msg> chat_new(past_msg);
     // if the past_msg ends with a newline, we must preserve it in the formatted version
     if (add_ass && !fmt_past_msg.empty() && fmt_past_msg.back() == '\n') {
@@ -1796,21 +1805,74 @@ std::string common_chat_format_single(const struct llama_model * model,
     };
     // format chat with new_msg
     chat_new.push_back(new_msg);
-    auto fmt_new_msg = common_chat_apply_template(model, tmpl, chat_new, add_ass);
+    auto fmt_new_msg = common_chat_apply_template(tmpl, chat_new, add_ass, use_jinja);
     // get the diff part
     ss << fmt_new_msg.substr(fmt_past_msg.size(), fmt_new_msg.size() - fmt_past_msg.size());
     return ss.str();
 }
 
-std::string common_chat_format_example(const struct llama_model * model,
-        const std::string & tmpl) {
+std::string common_chat_format_example(const common_chat_template & tmpl, bool use_jinja) {
     std::vector<common_chat_msg> msgs = {
         {"system",    "You are a helpful assistant"},
         {"user",      "Hello"},
         {"assistant", "Hi there"},
         {"user",      "How are you?"},
     };
-    return common_chat_apply_template(model, tmpl, msgs, true);
+    return common_chat_apply_template(tmpl, msgs, true, use_jinja);
+}
+
+common_chat_templates common_chat_templates_from_model(const struct llama_model * model, const std::string & chat_template_override)
+{
+    auto vocab = llama_model_get_vocab(model);
+    std::string default_template_src = chat_template_override;
+    std::string template_tool_use_src = chat_template_override;
+    bool has_explicit_template = !chat_template_override.empty();
+    if (chat_template_override.empty()) {
+        auto str = llama_model_chat_template(model, /* name */ nullptr);
+        if (str) {
+            default_template_src = str;
+            has_explicit_template = true;
+        }
+        str = llama_model_chat_template(model, /* name */ "tool_use");
+        if (str) {
+            template_tool_use_src = str;
+            has_explicit_template = true;
+        }
+    }
+    if (default_template_src.empty() || default_template_src == "chatml") {
+        if (!template_tool_use_src.empty()) {
+            default_template_src = template_tool_use_src;
+        } else {
+            default_template_src = R"(
+                {%- for message in messages -%}
+                    {{- "<|im_start|>" + message.role + "\n" + message.content + "<|im_end|>\n" -}}
+                {%- endfor -%}
+                {%- if add_generation_prompt -%}
+                    {{- "<|im_start|>assistant\n" -}}
+                {%- endif -%}
+            )";
+        }
+    }
+    const auto get_token = [&](llama_token token, const char * name, const char * jinja_variable_name) {
+        if (token == LLAMA_TOKEN_NULL) {
+            if (default_template_src.find(jinja_variable_name) != std::string::npos
+                || template_tool_use_src.find(jinja_variable_name) != std::string::npos) {
+                LOG_WRN("%s: warning: vocab does not have a %s token, jinja template won't work as intended.\n", __func__, name);
+            }
+            return std::string();
+        } else {
+            return common_token_to_piece(vocab, token, true);
+        }
+    };
+    auto token_bos = get_token(llama_vocab_bos(vocab), "BOS", "bos_token");
+    auto token_eos = get_token(llama_vocab_eos(vocab), "EOS", "eos_token");
+    return {
+        has_explicit_template,
+        std::make_unique<minja::chat_template>(default_template_src, token_bos, token_eos),
+        template_tool_use_src.empty()
+            ? nullptr
+            : std::make_unique<minja::chat_template>(template_tool_use_src, token_bos, token_eos)
+    };
 }
 
 //

common/common.h

@@ -334,6 +334,7 @@ struct common_params {
     std::string hostname      = "127.0.0.1";
     std::string public_path   = "";                                                                         // NOLINT
     std::string chat_template = "";                                                                         // NOLINT
+    bool use_jinja = false;                                                                                 // NOLINT
     bool enable_chat_template = true;
 
     std::vector<std::string> api_keys;
@@ -603,30 +604,43 @@ struct common_chat_msg {
     std::string content;
 };
 
-// Get the built-in chat template for the model. Return empty string if not present.
-std::string common_get_builtin_chat_template(const struct llama_model * model);
-
 // Check if the template supplied via "--chat-template" is supported or not. Returns true if it's valid
-bool common_chat_verify_template(const std::string & tmpl);
+bool common_chat_verify_template(const std::string & tmpl, bool use_jinja);
+
+namespace minja {
+    class chat_template;
+}
+
+typedef minja::chat_template common_chat_template;
+
+struct common_chat_templates {
+    bool has_explicit_template; // Model had builtin template or template overridde was specified.
+    std::unique_ptr<common_chat_template> template_default; // always set (defaults to chatml)
+    std::unique_ptr<common_chat_template> template_tool_use;
+};
 
 // CPP wrapper for llama_chat_apply_template
 // If the built-in template is not supported, we default to chatml
 // If the custom "tmpl" is not supported, we throw an error
-std::string common_chat_apply_template(const struct llama_model * model,
-        const std::string & tmpl,
+std::string common_chat_apply_template(
+        const common_chat_template & tmpl,
         const std::vector<common_chat_msg> & chat,
-        bool add_ass);
+        bool add_ass,
+        bool use_jinja);
 
 // Format single message, while taking into account the position of that message in chat history
-std::string common_chat_format_single(const struct llama_model * model,
-        const std::string & tmpl,
+std::string common_chat_format_single(
+        const common_chat_template & tmpl,
         const std::vector<common_chat_msg> & past_msg,
         const common_chat_msg & new_msg,
-        bool add_ass);
+        bool add_ass,
+        bool use_jinja);
 
 // Returns an example of formatted chat
-std::string common_chat_format_example(const struct llama_model * model,
-        const std::string & tmpl);
+std::string common_chat_format_example(
+    const common_chat_template & tmpl, bool use_jinja);
+
+common_chat_templates common_chat_templates_from_model(const struct llama_model * model, const std::string & chat_template_override);
 
 //
 // KV cache utils