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golang

Exporte + 基础指标

axing
axing
2025-08-25 / 0 评论 / 5 阅读 / 正在检测是否收录...
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一、解压 & 目录说明

unzip sys-exporter.zip -d sys-exporter
cd sys-exporter
tree -L 3
# .
# ├── Makefile
# ├── README.md
# ├── cmd/sys-exporter/main.go
# ├── go.mod
# └── internal/collectors/
#     ├── disk_usage.go
#     ├── disk_usage_test.go
#     ├── net_conn.go


#     ├── net_conn_test.go
#     ├── proc_rss.go
#     └── proc_rss_test.go

关键点：

使用自定义 Registry，同时注册 process 和 go collector。

/metrics 使用 promhttp.HandlerFor(reg, promhttp.HandlerOpts{EnableOpenMetrics:true})。

自带 /live、/ready，/ready 会尝试 Gather()，失败返回 503。

已挂好 /debug/pprof/*，方便做 CPU/内存采样。

三个示例指标：
  sys_mount_usage_ratio{mountpoint="/data"} （附带 sys_mount_used_bytes / sys_mount_total_bytes）
  
  sys_network_open_sockets{proto="tcp|udp", family="ipv4|ipv6"}
  
  sys_process_resident_memory_bytes（Exporter 进程自身 RSS）

二、运行脚手架（本地 make run）
2.1 前置准备（只做一次）

#下载go
wget https://go.dev/dl/go1.22.5.linux-amd64.tar.gz
#解压go
sudo tar -C /usr/local -xzf go1.22.5.linux-amd64.tar.gz
# 使用 vim：
sudo vim ~/.bashrc
#在文件的​​最后​​，添加以下几行：
export PATH=$PATH:/usr/local/go/bin
export GOPATH=$HOME/go
export PATH=$PATH:$GOPATH/bin
#立即生效
source ~/.bashrc
#验证安装
go version
#创建工作目录
mkdir -p ~/work && cd ~/work

2.2一键跑起来（/metrics、/live、/ready）

# 可选：拉依赖
make tidy

# 启动  如果没有data目录 需要提前创建
make run
# 日志应看到：sys-exporter listening on :9090 (mount=/data)
#报错
root@k8s-01:~/woke/sys-exporter# make run 
GO111MODULE=on go run ./cmd/sys-exporter 2025/08/25 07:47:24 sys-exporter listening on :9090 (mount=/data) 
root@k8s-01:~/woke/sys-exporter# make test 
GO111MODULE=on go test ./... -race -count=1 
# github.com/example/sys-exporter/internal/collectors [github.com/example/sys-exporter/internal/collectors.test] internal/collectors/disk_usage_test.go:22:37: undefined: testutil.NewGaugeFromDesc ? github.com/example/sys-exporter/cmd/sys-exporter [no test files] FAIL github.com/example/sys-exporter/internal/collectors [build failed] 
FAIL make: *** [Makefile:10: test] Error 1 root@k8s-01:~/woke/sys-exporter


这是单测里用了不存在的函数导致编译失败。prometheus/testutil 并没有 NewGaugeFromDesc 这个 API（我在示例里多写了一句检查 ratio 的代码）。解决方法：把那几行删掉，用 CollectAndCompare 做断言就够了。


#报错
root\@k8s-01:\~/woke/sys-exporter# make test
GO111MODULE=on go test ./... -race -count=1
?       github.com/example/sys-exporter/cmd/sys-exporter    \[no test files]
\--- FAIL: TestProcRSSCollector (0.00s)
proc\_rss\_test.go:31: metrics mismatch: +# HELP sys\_process\_resident\_memory\_bytes Resident memory (RSS) of the exporter process in bytes.
+# TYPE sys\_process\_resident\_memory\_bytes gauge
+sys\_process\_resident\_memory\_bytes 2.097152e+06

FAIL
FAIL    github.com/example/sys-exporter/internal/collectors    0.020s
FAIL
make: \*\*\* \[Makefile:10: test] Error 1
root\@k8s-01:~~/woke/sys-exporter# make tidy
go mod tidy
root\@k8s-01:~~/woke/sys-exporter# make test
GO111MODULE=on go test ./... -race -count=1
?       github.com/example/sys-exporter/cmd/sys-exporter    \[no test files]
\--- FAIL: TestProcRSSCollector (0.00s)
proc\_rss\_test.go:31: metrics mismatch: +# HELP sys\_process\_resident\_memory\_bytes Resident memory (RSS) of the exporter process in bytes.
+# TYPE sys\_process\_resident\_memory\_bytes gauge
+sys\_process\_resident\_memory\_bytes 2.097152e+06

FAIL
FAIL    github.com/example/sys-exporter/internal/collectors    0.018s
FAIL
make: \*\*\* \[Makefile:10: test] Error 1
root\@k8s-01:\~/woke/sys-exporter# cat  internal/collectors/disk\_usage\_test.go
package collectors

import (
"strings"
"testing"
#解决办法
用下面的内容覆盖 internal/collectors/disk_usage_test.go：
package collectors

import (
    "strings"
    "testing"
    "github.com/prometheus/client_golang/prometheus/testutil"
)

func TestDiskUsageCollector_Metrics(t *testing.T) {
    mock := func(path string) (total, avail uint64, err error) {
        // 100 total, 25 available -> used=75, ratio=0.75
        return 100, 25, nil
    }
    c := NewDiskUsageCollector("/data", mock)

    expected := 
# HELP sys_mount_total_bytes Total bytes for a mountpoint.
# TYPE sys_mount_total_bytes gauge
sys_mount_total_bytes{mountpoint="/data"} 100
# HELP sys_mount_used_bytes Used bytes for a mountpoint.
# TYPE sys_mount_used_bytes gauge
sys_mount_used_bytes{mountpoint="/data"} 75
# HELP sys_mount_usage_ratio Disk usage ratio (used/total) for a mountpoint.
# TYPE sys_mount_usage_ratio gauge
sys_mount_usage_ratio{mountpoint="/data"} 0.75

    if err := testutil.CollectAndCompare(c, strings.NewReader(expected)); err != nil {
        t.Fatalf("unexpected metrics diff: %v", err)
    }
}

"github.com/prometheus/client_golang/prometheus/testutil"


)

func TestDiskUsageCollector\_Metrics(t \*testing.T) {
mock := func(path string) (total, avail uint64, err error) {
// 100 total, 25 available -> used=75, ratio=0.75
return 100, 25, nil
}
c := NewDiskUsageCollector("/data", mock)


expected := 


# HELP sys\_mount\_total\_bytes Total bytes for a mountpoint.

# TYPE sys\_mount\_total\_bytes gauge

sys\_mount\_total\_bytes{mountpoint="/data"} 100

# HELP sys\_mount\_used\_bytes Used bytes for a mountpoint.

# TYPE sys\_mount\_used\_bytes gauge

sys\_mount\_used\_bytes{mountpoint="/data"} 75

# HELP sys\_mount\_usage\_ratio Disk usage ratio (used/total) for a mountpoint.

# TYPE sys\_mount\_usage\_ratio gauge

sys\_mount\_usage\_ratio{mountpoint="/data"} 0.75
\
if err := testutil.CollectAndCompare(c, strings.NewReader(expected)); err != nil {
t.Fatalf("unexpected metrics diff: %v", err)
}
}

你这个失败点在于单测期望的数值格式和PID 路径。

Prometheus 的文本输出里，浮点数经常是科学计数法（2.097152e+06），而你测试里写的是 2097152，导致对比失败。

你的测试里把 status 路径硬编码成 /fake/123/status，但实际 os.Getpid() 不一定是 123，最好用真实 PID 组路径。

把 internal/collectors/proc_rss_test.go 改成下面这样（两点都修了）：

package collectors

import (
    "os"
    "path/filepath"
    "strings"
    "testing"
    "github.com/prometheus/client_golang/prometheus/testutil"
)

func TestProcRSSCollector(t *testing.T) {
    root := "/fake"
    // 使用真实 PID 组路径，避免硬编码 123
    statusPath := filepath.Join(root, strconv.Itoa(os.Getpid()), "status")
    data := "Name:\tapp\nVmRSS:\t2048 kB\n" // 2048 KB => 2,097,152 bytes

    // 只要命中 <root>/<pid>/status 就返回我们伪造的数据
    reader := func(path string) ([]byte, error) {
        if path == statusPath {
            return []byte(data), nil
        }
        // 返回空数据，不要报错，Collector 会自己忽略
        return []byte(""), nil
    }

    c := NewProcRSSCollector(root, reader)

    // 注意：Prometheus 文本输出常是科学计数法，这里用 e+06
    exp := 
# HELP sys_process_resident_memory_bytes Resident memory (RSS) of the exporter process in bytes.
# TYPE sys_process_resident_memory_bytes gauge
sys_process_resident_memory_bytes 2.097152e+06

    if err := testutil.CollectAndCompare(c, strings.NewReader(exp)); err != nil {
        t.Fatalf("metrics mismatch: %v", err)
    }
}
#报错
root\@k8s-01:~~/woke/sys-exporter# vi   internal/collectors/disk\_usage\_test.go
root\@k8s-01:~~/woke/sys-exporter# ls
cmd  go.mod  go.sum  internal  Makefile  README.md
root\@k8s-01:~~/woke/sys-exporter# go clean -testcache
root\@k8s-01:~~/woke/sys-exporter# make test
GO111MODULE=on go test ./... -race -count=1

# github.com/example/sys-exporter/internal/collectors \[github.com/example/sys-exporter/internal/collectors.test]

internal/collectors/proc\_rss\_test.go:12:6: TestProcRSSCollector redeclared in this block
internal/collectors/disk\_usage\_test.go:12:6: other declaration of TestProcRSSCollector
internal/collectors/disk\_usage\_test.go:15:36: undefined: strconv
?       github.com/example/sys-exporter/cmd/sys-exporter    \[no test files]
FAIL    github.com/example/sys-exporter/internal/collectors \[build failed]
FAIL
make: \*\*\* \[Makefile:10: test] Error 1
root\@k8s-01:\~/woke/sys-exporter# cat    internal/collectors/disk\_usage\_test.go
package collectors

import (
"os"
"path/filepath"
"strings"
"testing"


"github.com/prometheus/client_golang/prometheus/testutil"


)

func TestProcRSSCollector(t \*testing.T) {
root := "/fake"
// 使用真实 PID 组路径，避免硬编码 123
statusPath := filepath.Join(root, strconv.Itoa(os.Getpid()), "status")
data := "Name:\tapp\nVmRSS:\t2048 kB\n" // 2048 KB => 2,097,152 bytes


// 只要命中 <root>/<pid>/status 就返回我们伪造的数据
reader := func(path string) ([]byte, error) {
    if path == statusPath {
        return []byte(data), nil
    }
    // 返回空数据，不要报错，Collector 会自己忽略
    return []byte(""), nil
}

c := NewProcRSSCollector(root, reader)

// 注意：Prometheus 文本输出常是科学计数法，这里用 e+06
exp := `

# HELP sys\_process\_resident\_memory\_bytes Resident memory (RSS) of the exporter process in bytes.

# TYPE sys\_process\_resident\_memory\_bytes gauge

sys\_process\_resident\_memory\_bytes 2.097152e+06
\`
if err := testutil.CollectAndCompare(c, strings.NewReader(exp)); err != nil {
t.Fatalf("metrics mismatch: %v", err)
}
}

你把 disk_usage_test.go 覆盖成了 proc_rss_test.go 的内容，所以现在：

出现了重复的 TestProcRSSCollector（两个文件里同名测试）。

且缺少 strconv 的 import

还原 disk_usage_test.go
把它恢复成“磁盘使用率”的测试（不要放 RSS 的测试）：
// internal/collectors/disk_usage_test.go
package collectors

import (
    "strings"
    "testing"

    "github.com/prometheus/client_golang/prometheus/testutil"
)

func TestDiskUsageCollector_Metrics(t *testing.T) {
    mock := func(path string) (total, avail uint64, err error) {
        // 100 total, 25 available -> used=75, ratio=0.75
        return 100, 25, nil
    }
    c := NewDiskUsageCollector("/data", mock)

    expected := `
# HELP sys_mount_total_bytes Total bytes for a mountpoint.
# TYPE sys_mount_total_bytes gauge
sys_mount_total_bytes{mountpoint="/data"} 100
# HELP sys_mount_used_bytes Used bytes for a mountpoint.
# TYPE sys_mount_used_bytes gauge
sys_mount_used_bytes{mountpoint="/data"} 75
# HELP sys_mount_usage_ratio Disk usage ratio (used/total) for a mountpoint.
# TYPE sys_mount_usage_ratio gauge
sys_mount_usage_ratio{mountpoint="/data"} 0.75
`
    if err := testutil.CollectAndCompare(c, strings.NewReader(expected)); err != nil {
        t.Fatalf("unexpected metrics diff: %v", err)
    }
}


修正 proc_rss_test.go
确保它只包含 RSS 的测试，且 加上 strconv 的 import：
// internal/collectors/proc_rss_test.go
package collectors

import (
    "os"
    "path/filepath"
    "strconv"
    "strings"
    "testing"

    "github.com/prometheus/client_golang/prometheus/testutil"
)

func TestProcRSSCollector(t *testing.T) {
    root := "/fake"
    statusPath := filepath.Join(root, strconv.Itoa(os.Getpid()), "status")
    data := "Name:\tapp\nVmRSS:\t2048 kB\n" // 2048 KB => 2,097,152 bytes

    reader := func(path string) ([]byte, error) {
        if path == statusPath {
            return []byte(data), nil
        }
        return []byte(""), nil
    }

    c := NewProcRSSCollector(root, reader)

    exp := `
# HELP sys_process_resident_memory_bytes Resident memory (RSS) of the exporter process in bytes.
# TYPE sys_process_resident_memory_bytes gauge
sys_process_resident_memory_bytes 2.097152e+06
`
    if err := testutil.CollectAndCompare(c, strings.NewReader(exp)); err != nil {
        t.Fatalf("metrics mismatch: %v", err)
    }
}

#正常
root@k8s-01:~/woke/sys-exporter# go clean -testcache make test 
GO111MODULE=on go test ./... -race -count=1 ? 
github.com/example/sys-exporter/cmd/sys-exporter [no test files] ok 
github.com/example/sys-exporter/internal/collectors 1.019s
#报错
root@k8s-01:~/woke/sys-exporter# make bench
GO111MODULE=on go test ./... -run=^$ -bench=. -benchmem -count=1 -cpuprofile cpu.out -memprofile mem.out
cannot use -cpuprofile flag with multiple packages
make: *** [Makefile:13: bench] Error 1

#cannot use -cpuprofile flag with multiple packages
意思是：你下了 -cpuprofile 参数，但 go test ./... 会一次性跑多个包（cmd/... 和 internal/...），Go 不允许把多个包的基准同时写到一个 cpu.out 里。

解决方法
只 bench 你有基准的那个包（internal/collectors），而不是所有 ./...。

bench:
    GO111MODULE=on go test ./internal/collectors -run=^$$ -bench=. -benchmem -count=1 -cpuprofile cpu.out -memprofile mem.out
    @echo ""
    @echo "CPU profile: cpu.out  | Mem profile: mem.out"
    @echo "Open an interactive view:"
    @echo "  go tool pprof -http=:9999 cpu.out"


执行make bench
能正常生成 cpu.out 和 mem.out
#报错
root\@k8s-01:\~/woke/sys-exporter# make bench
GO111MODULE=on go test ./internal/collectors -run=^\$ -bench=. -benchmem -count=1 -cpuprofile cpu.out -memprofile mem.out
PASS
ok      github.com/example/sys-exporter/internal/collectors    0.252s

CPU profile: cpu.out  | Mem profile: mem.out
Open an interactive view:
go tool pprof -http=:9999 cpu.out
root\@k8s-01:~~/woke/sys-exporter# ls
cmd  collectors.test  cpu.out  go.mod  go.sum  internal  Makefile  mem.out  README.md
root\@k8s-01:~~/woke/sys-exporter# go tool pprof -http=:9999 cpu.out
Serving web UI on [http://localhost:9999](http://localhost:9999)
Couldn't find a suitable web browser!

Set the BROWSER environment variable to your desired browser.

浏览器[http://192.168.30.180:9999/](http://192.168.30.180:9999/) 打不开


这是正常现象：现在的 pprof Web UI 只监听在本机回环地址（localhost），所以你从别的机器用 http://192.168.30.180:9999 打不开


#解决
go tool pprof -http=0.0.0.0:9999 cpu.out


如果浏览器打开以后显示：Could not execute dot; may need to install graphviz.

那就需要安装 Graphviz
sudo apt-get install -y graphviz
sudo yum install -y graphviz

重新打开 pprof Web
go tool pprof -http=0.0.0.0:9999 cpu.out
这时点击 “View → Graph” 或 “Flame Graph” 就能显示图像了。
root@k8s-01:~/woke/sys-exporter# go tool pprof -http=0.0.0.0:9999 cpu.out
Serving web UI on http://0.0.0.0:9999
Couldn't find a suitable web browser!

Set the BROWSER environment variable to your desired browser.

mer7rzvw.png
mer7scay.png

cd ~/woke/sys-exporter
LISTEN_ADDR=":9090" MOUNTPOINT="/data" make run
# 看到日志：sys-exporter listening on :9090 (mount=/data)
# 抓在线 profile 并用 Web UI 展示
用正确的 URL抓在线 profile
在 exporter 正常监听后再执行（仍然在服务器上）：
go tool pprof -http=0.0.0.0:9999 http://localhost:9090/debug/pprof/profile?seconds=15
注意要点：

-http=0.0.0.0:9999 只是 Web UI 的监听地址；

profile 的 URL 要作为最后一个参数单独给出（别写到 -http= 里）；

如果你把 exporter 绑在了别的端口，比如 :9100，就把 URL 换成：
http://localhost:9100/debug/pprof/profile?seconds=15

mer7ky5u.png

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