build: stop tracking generated tutorial artifacts (#215)

* build: stop tracking generated tutorial artifacts

* build: avoid duplicating the goroutine offset

---------

Co-authored-by: LinuxDev9002 <i@littlefisher.me>

src/31-goroutine/.gitignore

@@ -6,3 +6,4 @@ package.json
 package.yaml
 ecli
 goroutine
+/go-server-http/main

src/31-goroutine/README.md

@@ -75,21 +75,31 @@ char LICENSE[] SEC("license") = "GPL";
 
 ## Running the Program
 
-To run this tracing program, follow these steps:
+Run the following commands from `src/31-goroutine`. The eBPF program attaches to
+`./go-server-http/main`, so the target binary is generated locally rather than
+stored in Git. Use Go 1.17.13 to match the checked-in `GOID_OFFSET` value; verify
+the offset before tracing a binary built with another Go version.
 
-1. **Compile the eBPF Code**: Compile the eBPF program using a compiler like `ecc` (eBPF Compiler Collection) and generate a package that can be loaded by an eBPF loader.
+1. **Build and start the target program**: Keep the HTTP server running, then use a second terminal for the remaining commands.
+
+    ```bash
+    make -C go-server-http
+    sudo ./go-server-http/main
+    ```
+
+2. **Compile the eBPF Code**: Compile the eBPF program using a compiler like `ecc` (eBPF Compiler Collection) and generate a package that can be loaded by an eBPF loader.
 
     ```bash
     ecc goroutine.bpf.c goroutine.h
     ```
 
-2. **Run the eBPF Program**: Use an eBPF loader to run the compiled eBPF program.
+3. **Run the eBPF Program**: Use an eBPF loader to run the compiled eBPF program.
 
     ```bash
     ecli-rs run package.json
     ```
 
-3. **Output**: The program will output the state transitions of goroutines along with their `goid`, `pid`, and `tgid`. Here’s an example of the output:
+4. **Output**: The program will output the state transitions of goroutines along with their `goid`, `pid`, and `tgid`. Here’s an example of the output:
 
     ```console
     TIME     STATE       GOID   PID    TGID   

src/31-goroutine/README.zh.md

@@ -73,21 +73,31 @@ char LICENSE[] SEC("license") = "GPL";
 
 ## 运行程序
 
-要运行此跟踪程序，请按照以下步骤操作：
+请从 `src/31-goroutine` 目录运行以下命令。eBPF 程序会附加到
+`./go-server-http/main`，因此目标二进制文件应在本地生成，不再存储在 Git
+中。请使用 Go 1.17.13 以匹配当前 `GOID_OFFSET`；如果使用其他 Go 版本构建，
+请先重新验证该偏移量。
 
-1. **编译 eBPF 代码**：使用类似 `ecc`（eBPF 编译集合）这样的编译器编译 eBPF 程序，并生成一个可以由 eBPF 加载器加载的包。
+1. **构建并启动目标程序**：保持 HTTP 服务运行，然后在另一个终端执行后续命令。
+
+    ```bash
+    make -C go-server-http
+    sudo ./go-server-http/main
+    ```
+
+2. **编译 eBPF 代码**：使用类似 `ecc`（eBPF 编译集合）这样的编译器编译 eBPF 程序，并生成一个可以由 eBPF 加载器加载的包。
 
     ```bash
     ecc goroutine.bpf.c goroutine.h
     ```
 
-2. **运行 eBPF 程序**：使用 eBPF 加载器运行编译后的 eBPF 程序。
+3. **运行 eBPF 程序**：使用 eBPF 加载器运行编译后的 eBPF 程序。
 
     ```bash
     ecli-rs run package.json
     ```
 
-3. **输出**：程序将输出协程的状态转换及其 `goid`、`pid` 和 `tgid`。以下是一个示例输出：
+4. **输出**：程序将输出协程的状态转换及其 `goid`、`pid` 和 `tgid`。以下是一个示例输出：
 
     ```console
     TIME     STATE       GOID   PID    TGID   

src/31-goroutine/go-server-http/Makefile

@@ -0,0 +1,16 @@
+GO ?= go
+BINARY := main
+
+.PHONY: all clean
+all: $(BINARY)
+
+$(BINARY): main.go
+	@version="$$($(GO) version)"; \
+	case "$$version" in \
+	  *" go1.17."*) ;; \
+	  *) echo "warning: the goroutine goid offset was validated with Go 1.17; verify it for $$version" >&2 ;; \
+	esac
+	$(GO) build -o $@ $<
+
+clean:
+	rm -f $(BINARY)