### Install Apollo Adapter

Source: https://github.com/gogf/gf/blob/master/contrib/config/apollo/README.MD

Install the Apollo configuration adapter for GoFrame using go get.

```bash
go get -u github.com/gogf/gf/contrib/config/apollo/v2
```

--------------------------------

### Install Kubecm Package

Source: https://github.com/gogf/gf/blob/master/contrib/config/kubecm/README.MD

Install the kubecm package using go get.

```bash
go get -u github.com/gogf/gf/contrib/config/kubecm/v2
```

--------------------------------

### Install Polaris GoFrame Adapter

Source: https://github.com/gogf/gf/blob/master/contrib/config/polaris/README.MD

Install the Polaris configuration adapter for GoFrame using go get.

```bash
go get -u github.com/gogf/gf/contrib/config/polaris/v2
```

--------------------------------

### Install Multiple Database Drivers

Source: https://github.com/gogf/gf/blob/master/contrib/drivers/README.MD

A list of `go get` commands to install various database drivers for gdb. Choose the one relevant to your project.

```shell
go get github.com/gogf/gf/contrib/drivers/clickhouse/v2@latest
go get github.com/gogf/gf/contrib/drivers/dm/v2@latest
go get github.com/gogf/gf/contrib/drivers/gaussdb/v2@latest
go get github.com/gogf/gf/contrib/drivers/mariadb/v2@latest
go get github.com/gogf/gf/contrib/drivers/mssql/v2@latest
go get github.com/gogf/gf/contrib/drivers/oceanbase/v2@latest
go get github.com/gogf/gf/contrib/drivers/oracle/v2@latest
go get github.com/gogf/gf/contrib/drivers/pgsql/v2@latest
go get github.com/gogf/gf/contrib/drivers/sqlite/v2@latest
go get github.com/gogf/gf/contrib/drivers/sqlitecgo/v2@latest
go get github.com/gogf/gf/contrib/drivers/tidb/v2@latest
```

--------------------------------

### File Registry Client Example

Source: https://github.com/gogf/gf/blob/master/contrib/registry/file/README.MD

Example of a client using the file registry. It initializes the registry and then makes multiple requests to a registered service.

```go
package main

import (
	"fmt"
	"time"

	"github.com/gogf/gf/contrib/registry/file/v2"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/net/gsvc"
	"github.com/gogf/gf/v2/os/gctx"
	"github.com/gogf/gf/v2/os/gfile"
)

func main() {
	gsvc.SetRegistry(file.New(gfile.Temp("gsvc")))

	client := g.Client()
	for i := 0; i < 100; i++ {
		res, err := client.Get(gctx.New(), `http://hello.svc/`)
		if err != nil {
			panic(err)
		}
		fmt.Println(res.ReadAllString())
		res.Close()
		time.Sleep(time.Second)
	}
}

```

--------------------------------

### Install File Registry

Source: https://github.com/gogf/gf/blob/master/contrib/registry/file/README.MD

Install the file registry component using go get. It is recommended to use go.mod for dependency management.

```go
go get -u -v github.com/gogf/gf/contrib/registry/file/v2
```

```go
require github.com/gogf/gf/contrib/registry/file/v2 latest
```

--------------------------------

### File Registry Server Example

Source: https://github.com/gogf/gf/blob/master/contrib/registry/file/README.MD

Example of a server using the file registry. It sets up the registry with a temporary directory and binds a handler for incoming requests.

```go
package main

import (
	"github.com/gogf/gf/contrib/registry/file/v2"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/net/ghttp"
	"github.com/gogf/gf/v2/net/gsvc"
	"github.com/gogf/gf/v2/os/gfile"
)

func main() {
	gsvc.SetRegistry(file.New(gfile.Temp("gsvc")))

	s := g.Server(`hello.svc`)
	s.BindHandler("/", func(r *ghttp.Request) {
		g.Log().Info(r.Context(), `request received`)
		r.Response.Write(`Hello world`)
	})
	s.Run()
}

```

--------------------------------

### Install GoFrame Framework

Source: https://github.com/gogf/gf/blob/master/README.MD

Use this command to install the GoFrame framework. Ensure you are using Go version 2 or higher.

```bash
go get -u github.com/gogf/gf/v2
```

--------------------------------

### Install Consul Adapter

Source: https://github.com/gogf/gf/blob/master/contrib/config/consul/README.md

Install the Consul configuration adapter for GoFrame using go get.

```go
go get -u github.com/gogf/gf/contrib/config/consul/v2
```

--------------------------------

### Install otelmetric v2

Source: https://github.com/gogf/gf/blob/master/contrib/metric/otelmetric/README.MD

Install the otelmetric module using go get. It is recommended to use go.mod for managing dependencies.

```go
go get -u -v github.com/gogf/gf/contrib/metric/otelmetric/v2
```

```go
require github.com/gogf/gf/contrib/metric/otelmetric/v2 latest
```

--------------------------------

### Install MySQL Driver

Source: https://github.com/gogf/gf/blob/master/contrib/drivers/README.MD

Use `go get` to install the MySQL driver for gdb. This command fetches the latest version.

```shell
go get github.com/gogf/gf/contrib/drivers/mysql/v2@latest
```

--------------------------------

### Example: Sending a GET Request

Source: https://github.com/gogf/gf/wiki/功能模块设计/HTTP客户端

Demonstrates how to send a GET request using the standalone ghttp.Get function and process the response.

```go
package main

import (
	"fmt"
	"gitee.com/johng/gf/g/net/ghttp"
)

func main() {
	if r, e := ghttp.Get("http://johng.cn"); e != nil {
		fmt.Println(e)
	} else {
		fmt.Println(string(r.ReadAll()))
		r.Close()
	}
}
```

--------------------------------

### Install ZooKeeper Registry

Source: https://github.com/gogf/gf/blob/master/contrib/registry/zookeeper/README.MD

Install the ZooKeeper registry component for GoFrame using go get or go.mod.

```bash
go get -u -v github.com/gogf/gf/contrib/registry/zookeeper/v2
```

```go
require github.com/gogf/gf/contrib/registry/zookeeper/v2 latest
```

--------------------------------

### Install GoFrame Redis Adapter

Source: https://github.com/gogf/gf/blob/master/contrib/nosql/redis/README.MD

Install the Redis adapter for GoFrame using go get. This command fetches the necessary package for Redis integration.

```bash
go get -u github.com/gogf/gf/contrib/nosql/redis/v2
```

--------------------------------

### Example YAML Configuration

Source: https://github.com/gogf/gf/wiki/Web服务开发/配置管理

A sample configuration file demonstrating settings for template engine directory and MySQL database clusters.

```yaml
# 模板引擎目录
viewpath: /home/www/templates/
# MySQL数据库配置
database:
    default:
        - host:     127.0.0.1
          port:     3306
          user:     root
          pass:     123456
          name:     test
          type:     mysql
          role:     master
          charset:  utf-8
          priority: 1
        - host:     127.0.0.1
          port:     3306
          user:     root
          pass:     123456
          name:     test
          type:     mysql
          role:     master
          charset:  utf-8
          priority: 1
```

--------------------------------

### Etcd Registry Client Example

Source: https://github.com/gogf/gf/blob/master/contrib/registry/etcd/README.MD

Example of a GoFrame client using etcd for service discovery and making requests. It uses a round-robin load balancing strategy.

```go
package main

import (
	"fmt"
	"time"

	"github.com/gogf/gf/contrib/registry/etcd/v2"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/net/gsel"
	"github.com/gogf/gf/v2/net/gsvc"
	"github.com/gogf/gf/v2/os/gctx"
)

func main() {
	gsvc.SetRegistry(etcd.New(`127.0.0.1:2379`))
	gsel.SetBuilder(gsel.NewBuilderRoundRobin())

	client := g.Client()
	for i := 0; i < 100; i++ {
		res, err := client.Get(gctx.New(), `http://hello.svc/`)
		if err != nil {
			panic(err)
		}
		fmt.Println(res.ReadAllString())
		res.Close()
		time.Sleep(time.Second)
	}
}
```

--------------------------------

### Start Local Docker Services

Source: https://github.com/gogf/gf/blob/master/CLAUDE.md

Starts the default local stack of backing services required for certain tests. Use 'make docker cmd=start svc=<service_name>' to start specific services.

```bash
make docker
```

--------------------------------

### Etcd Registry Server Example

Source: https://github.com/gogf/gf/blob/master/contrib/registry/etcd/README.MD

Example of a GoFrame server using etcd for service registration. Ensure etcd is running at 127.0.0.1:2379.

```go
package main

import (
	"github.com/gogf/gf/contrib/registry/etcd/v2"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/net/ghttp"
	"github.com/gogf/gf/v2/net/gsvc"
)

func main() {
	gsvc.SetRegistry(etcd.New(`127.0.0.1:2379`))

	s := g.Server(`hello.svc`)
	s.BindHandler("/", func(r *ghttp.Request) {
		g.Log().Info(r.Context(), `request received`)
		r.Response.Write(`Hello world`)
	})
	s.Run()
}
```

--------------------------------

### Install Nacos Adapter

Source: https://github.com/gogf/gf/blob/master/contrib/config/nacos/README.MD

Install the Nacos configuration adapter for GoFrame v2 using go get.

```bash
go get -u github.com/gogf/gf/contrib/config/nacos/v2
```

--------------------------------

### Import Boot Package in Main Application

Source: https://github.com/gogf/gf/blob/master/contrib/config/apollo/README.MD

Import the custom boot package in your main.go to ensure the Apollo configuration is loaded. This example demonstrates checking configuration availability, retrieving all data, and getting a specific value.

```go
package main

import (
	_ "github.com/gogf/gf/example/config/apollo/boot"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gctx"
)

func main() {
	var ctx = gctx.GetInitCtx()

	// Available checks.
	g.Dump(g.Cfg().Available(ctx))

	// All key-value configurations.
	g.Dump(g.Cfg().Data(ctx))

	// Retrieve certain value by key.
	g.Dump(g.Cfg().MustGet(ctx, "server.address"))
}
```

--------------------------------

### Install gf CLI (Go Modules)

Source: https://github.com/gogf/gf/blob/master/cmd/gf/README.MD

Installs the gf CLI tool using Go modules. You can install the latest version or a specific version.

```shell
go install github.com/gogf/gf/cmd/gf/v2@latest # latest version
```

```shell
go install github.com/gogf/gf/cmd/gf/v2@v2.5.5 # certain version(should be >= v2.5.5)
```

--------------------------------

### Install gf CLI (Mac/Linux)

Source: https://github.com/gogf/gf/blob/master/cmd/gf/README.MD

Installs the gf CLI tool using a pre-compiled binary from GitHub releases. It downloads the binary, makes it executable, installs it, and then removes the downloaded file. Note: If using zsh, you might need to alias gf to resolve conflicts with git fetch.

```shell
wget -O gf https://github.com/gogf/gf/releases/latest/download/gf_$(go env GOOS)_$(go env GOARCH) && chmod +x gf && ./gf install -y && rm ./gf
```

--------------------------------

### Install GoFrame Polaris Registry

Source: https://github.com/gogf/gf/blob/master/contrib/registry/polaris/README.MD

Install the Polaris registry component for GoFrame using go get.

```bash
go get -u -v github.com/gogf/gf/contrib/registry/polaris/v2
```

--------------------------------

### Import Boot Package in Main Application

Source: https://github.com/gogf/gf/blob/master/contrib/config/polaris/README.MD

Import the custom boot package at the top of your main.go to ensure the Polaris configuration adapter is active. This example demonstrates how to access configuration values after setup.

```go
package main

import (
    _ "github.com/gogf/gf/example/config/polaris/boot"
    
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/os/gctx"
)

func main() {
    var ctx = gctx.GetInitCtx()
    
    // Available checks.
    g.Dump(g.Cfg().Available(ctx))
    
    // All key-value configurations.
    g.Dump(g.Cfg().Data(ctx))
    
    // Retrieve certain value by key.
    g.Dump(g.Cfg().MustGet(ctx, "server.address"))
}
```

--------------------------------

### Simple Echo TCPServer Example

Source: https://github.com/gogf/gf/wiki/网络服务开发/TCPServer

Demonstrates how to create and run a basic TCP echo server. It listens on a specified address and echoes back any received data to the client.

```go
package main

import (
    "net"
    "gitee.com/johng/gf/g/net/gtcp"
)

func main() {
    gtcp.NewServer(":8999", func(conn net.Conn) {
        for {
            buffer := make([]byte, 1024)
            if length, err := conn.Read(buffer); err == nil {
                conn.Write(append([]byte("> "), buffer[0 : length]...))
            }
        }
    }).Run()
```

--------------------------------

### Import Boot Package in Main Application

Source: https://github.com/gogf/gf/blob/master/contrib/config/consul/README.md

Import the custom boot package at the top of your main.go file to ensure the Consul configuration adapter is initialized before application logic runs. This example demonstrates how to access configuration values after setup.

```go
package main

import (
	_ "github.com/gogf/gf/example/config/consul/boot"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gctx"
)

func main() {
	var ctx = gctx.GetInitCtx()

	// Available checks.
	g.Dump(g.Cfg().Available(ctx))

	// All key-value configurations.
	g.Dump(g.Cfg().Data(ctx))

	// Retrieve certain value by key.
	g.Dump(g.Cfg().MustGet(ctx, "redis.addr"))
}
```

--------------------------------

### Polaris Service Server Example

Source: https://github.com/gogf/gf/blob/master/contrib/registry/polaris/README.MD

Example of a GoFrame server using Polaris for service registration. Ensure Polaris server is running and accessible.

```go
package main

import (
    "github.com/polarismesh/polaris-go/pkg/config"
    
    "github.com/gogf/gf/contrib/registry/polaris/v2"
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/net/ghttp"
    "github.com/gogf/gf/v2/net/gsvc"
)

func main() {
    conf := config.NewDefaultConfiguration([]string{"183.47.111.80:8091"})
    
    // TTL egt 2*time.Second
    gsvc.SetRegistry(polaris.NewWithConfig(conf, polaris.WithTTL(10)))
    
    s := g.Server(`hello.svc`)
    s.BindHandler("/", func(r *ghttp.Request) {
        g.Log().Info(r.Context(), `request received`)
        r.Response.Write(`Hello world`)
    })
    s.Run()
}
```

--------------------------------

### Example Kubernetes ConfigMap

Source: https://github.com/gogf/gf/blob/master/contrib/config/kubecm/README.MD

An example of a Kubernetes ConfigMap resource containing configuration data.

```yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: test-configmap
data:
  config.yaml: |
    # HTTP service.
    server:
      address:          ":8888"
      openapiPath:      "/api.json"
      swaggerPath:      "/swagger"
      accessLogEnabled: true
```

--------------------------------

### Registering "Hello World" with Domain Binding

Source: https://github.com/gogf/gf/wiki/Web服务开发/服务注册

Example of registering a callback function to a specific domain ('localhost') using the Domain method. Accessing this service via other domains (e.g., 127.0.0.1) will result in a 404 error.

```go
package main

import "gitee.com/johng/gf/g/net/ghttp"

func init() {
    ghttp.GetServer().Domain("localhost").BindHandler("/", func(r *ghttp.Request) {
        r.Response.WriteString("Hello World!")
    })
}
```

--------------------------------

### Main Application with MySQL Driver

Source: https://github.com/gogf/gf/blob/master/contrib/drivers/README.MD

Example of importing the MySQL driver in `main.go` alongside other necessary packages. The driver is typically imported at the top of the file.

```go
package main

import (
	_ "github.com/gogf/gf/contrib/drivers/mysql/v2"

	// Other imported packages.
)

func main() {
	// Main logics.
}
```

--------------------------------

### Polaris Service Client Example

Source: https://github.com/gogf/gf/blob/master/contrib/registry/polaris/README.MD

Example of a GoFrame client using Polaris for service discovery. This client will repeatedly call the 'hello.svc' service.

```go
package main

import (
    "fmt"
    "time"
    
    "github.com/polarismesh/polaris-go/pkg/config"
    
    "github.com/gogf/gf/contrib/registry/polaris/v2"
    
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/net/gsvc"
    "github.com/gogf/gf/v2/os/gctx"
)

func main() {
    conf := config.NewDefaultConfiguration([]string{"183.47.111.80:8091"})
    
    gsvc.SetRegistry(polaris.NewWithConfig(conf, polaris.WithTTL(10)))
    
    for i := 0; i < 100; i++ {
        res, err := g.Client().Get(gctx.New(), `http://hello.svc/`)
        if err != nil {
            panic(err)
        }
        fmt.Println(res.ReadAllString())
        res.Close()
        time.Sleep(time.Second)
    }
}
```

--------------------------------

### Install GoFrame Consul Registry

Source: https://github.com/gogf/gf/blob/master/contrib/registry/consul/README.MD

Install the GoFrame Consul registry component using go get or by adding it to your go.mod file.

```bash
go get -u github.com/gogf/gf/contrib/registry/consul/v2
```

```bash
require github.com/gogf/gf/contrib/registry/consul/v2 latest
```

--------------------------------

### Nacos Server Example

Source: https://github.com/gogf/gf/blob/master/contrib/registry/nacos/README.MD

Example of a GoFrame server using Nacos for service registration. It sets up the Nacos registry and binds a handler for the root path.

```go
package main

import (
	"github.com/gogf/gf/contrib/registry/nacos/v2"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/net/ghttp"
	"github.com/gogf/gf/v2/net/gsvc"
)

func main() {
	gsvc.SetRegistry(nacos.New(`127.0.0.1:8848`).
        SetClusterName("DEFAULT").
        SetGroupName("DEFAULT_GROUP"))

	s := g.Server(`hello.svc`)
	s.BindHandler("/", func(r *ghttp.Request) {
		g.Log().Info(r.Context(), `request received`)
		r.Response.Write(`Hello world`)
	})
	s.Run()
}
```

--------------------------------

### Nacos Client Example

Source: https://github.com/gogf/gf/blob/master/contrib/registry/nacos/README.MD

Example of a GoFrame client using Nacos for service discovery. It sets up the Nacos registry, a round-robin load balancer, and makes multiple requests to a registered service.

```go
package main

import (
	"fmt"
	"time"

	"github.com/gogf/gf/contrib/registry/nacos/v2"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/net/gsel"
	"github.com/gogf/gf/v2/net/gsvc"
	"github.com/gogf/gf/v2/os/gctx"
)

func main() {
	gsvc.SetRegistry(nacos.New(`127.0.0.1:8848`))
	gsel.SetBuilder(gsel.NewBuilderRoundRobin())

	client := g.Client()
	for i := 0; i < 100; i++ {
		res, err := client.Get(gctx.New(), `http://hello.svc/`)
		if err != nil {
			panic(err)
		}
		fmt.Println(res.ReadAllString())
		res.Close()
		time.Sleep(time.Second)
	}
}
```

--------------------------------

### Get Command-Line Options by Key

Source: https://github.com/gogf/gf/wiki/功能模块设计/命令行模块

Retrieve command-line options by their key name. Supports formats like '--key=value' or '-key=value'.

```go
gcmd.Option.Get("timeout")
```

```go
gcmd.Option.Get("logpath")
```

--------------------------------

### Send GET Request and Print Response

Source: https://github.com/gogf/gf/wiki/功能模块设计/HTTP客户端

Demonstrates how to send a GET request using the ghttp.Get function and process the response. Remember to close the response object after reading its content.

```go
if r, e := ghttp.Get("http://johng.cn"); e != nil {
    fmt.Println(e)
} else {
    fmt.Println(string(r.ReadAll()))
    r.Close()
}
```

--------------------------------

### Install etcd Registry

Source: https://github.com/gogf/gf/blob/master/contrib/registry/etcd/README.MD

Install the etcd registry component for GoFrame. It is recommended to use go.mod for managing dependencies.

```go
go get -u -v github.com/gogf/gf/contrib/registry/etcd/v2
```

```go
require github.com/gogf/gf/contrib/registry/etcd/v2 latest
```

--------------------------------

### Session Increment Example in Go

Source: https://github.com/gogf/gf/wiki/Web服务开发/Session

Demonstrates how to increment a session variable. Access the session via `r.Session` and use `GetInt` and `Set` to manage the counter. This example is suitable for tracking user visits or simple state.

```go
package demo

import (
    "strconv"
    "gitee.com/johng/gf/g/net/ghttp"
)

func init() {
    ghttp.GetServer().BindHandler("/session", Session)
}

func Session(r *ghttp.Request) {
    id := r.Session.GetInt("id")
    r.Session.Set("id", id + 1)
    r.Response.WriteString("id:" + strconv.Itoa(id))
}
```

--------------------------------

### Import MariaDB Driver

Source: https://github.com/gogf/gf/blob/master/contrib/drivers/README.MD

Import the MariaDB driver for use with gdb. Ensure the driver is installed before importing.

```go
import _ "github.com/gogf/gf/contrib/drivers/mariadb/v2"
```

--------------------------------

### Example: File Upload

Source: https://github.com/gogf/gf/wiki/功能模块设计/HTTP客户端

Illustrates how to perform a file upload using a POST request. The file is specified using the '@file:' prefix followed by the file path.

```go
package main

import (
	"fmt"
	"gitee.com/johng/gf/g/net/ghttp"
	"gitee.com/johng/gf/g/os/glog"
)

func main() {
	path := "/home/john/Workspace/Go/gitee.com/johng/gf/version.go"
	r, e := ghttp.Post("http://127.0.0.1:8199/upload", "name=john&age=18&upload-file=@file:" + path)
	if e != nil {
		glog.Error(e)
	} else {
		fmt.Println(string(r.ReadAll()))
		r.Close()
	}
}
```

--------------------------------

### Modify Configuration Directory via Command Line

Source: https://github.com/gogf/gf/wiki/Web服务开发/配置管理

Example of how to specify a custom configuration directory using a command-line argument.

```shell
./main --cfgpath=/opt/config/
```

--------------------------------

### Basic otelmetric Example

Source: https://github.com/gogf/gf/blob/master/contrib/metric/otelmetric/README.MD

Demonstrates the usage of various metric types (Counter, UpDownCounter, Histogram, Observable metrics) with OpenTelemetry exporter and Prometheus HTTP handler.

```go
package main

import (
	"context"

	"github.com/prometheus/client_golang/prometheus/promhttp"
	"go.opentelemetry.io/otel/exporters/prometheus"
	"go.opentelemetry.io/otel/sdk/metric"

	"github.com/gogf/gf/contrib/metric/otelmetric/v2"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/net/ghttp"
	"github.com/gogf/gf/v2/os/gctx"
	"github.com/gogf/gf/v2/os/gmetric"
)

var (
	meter = gmetric.GetGlobalProvider().Meter(gmetric.MeterOption{
		Instrument:        "github.com/gogf/gf/example/metric/basic",
		InstrumentVersion: "v1.0",
	})
	counter = meter.MustCounter(
		"goframe.metric.demo.counter",
		gmetric.MetricOption{
			Help: "This is a simple demo for Counter usage",
			Unit: "bytes",
			Attributes: gmetric.Attributes{
				gmetric.NewAttribute("const_label_1", 1),
			},
		},
	)
	upDownCounter = meter.MustUpDownCounter(
		"goframe.metric.demo.updown_counter",
		gmetric.MetricOption{
			Help: "This is a simple demo for UpDownCounter usage",
			Unit: "%",
			Attributes: gmetric.Attributes{
				gmetric.NewAttribute("const_label_2", 2),
			},
		},
	)
	histogram = meter.MustHistogram(
		"goframe.metric.demo.histogram",
		gmetric.MetricOption{
			Help: "This is a simple demo for histogram usage",
			Unit: "ms",
			Attributes: gmetric.Attributes{
				gmetric.NewAttribute("const_label_3", 3),
			},
			Buckets: []float64{0, 10, 20, 50, 100, 500, 1000, 2000, 5000, 10000},
		},
	)
	observableCounter = meter.MustObservableCounter(
		"goframe.metric.demo.observable_counter",
		gmetric.MetricOption{
			Help: "This is a simple demo for ObservableCounter usage",
			Unit: "%",
			Attributes: gmetric.Attributes{
				gmetric.NewAttribute("const_label_4", 4),
			},
		},
	)
	observableUpDownCounter = meter.MustObservableUpDownCounter(
		"goframe.metric.demo.observable_updown_counter",
		gmetric.MetricOption{
			Help: "This is a simple demo for ObservableUpDownCounter usage",
			Unit: "%",
			Attributes: gmetric.Attributes{
				gmetric.NewAttribute("const_label_5", 5),
			},
		},
	)
	observableGauge = meter.MustObservableGauge(
		"goframe.metric.demo.observable_gauge",
		gmetric.MetricOption{
			Help: "This is a simple demo for ObservableGauge usage",
			Unit: "%",
			Attributes: gmetric.Attributes{
				gmetric.NewAttribute("const_label_6", 6),
			},
		},
	)
)

func main() {
	var ctx = gctx.New()

	// Callback for observable metrics.
	meter.MustRegisterCallback(func(ctx context.Context, obs gmetric.Observer) error {
		obs.Observe(observableCounter, 10)
		obs.Observe(observableUpDownCounter, 20)
		obs.Observe(observableGauge, 30)
		return nil
	}, observableCounter, observableUpDownCounter, observableGauge)

	// Prometheus exporter to export metrics as Prometheus format.
	exporter, err := prometheus.New(
		prometheus.WithoutCounterSuffixes(),
		prometheus.WithoutUnits(),
	)
	if err != nil {
		g.Log().Fatal(ctx, err)
	}

	// OpenTelemetry provider.
	provider := otelmetric.MustProvider(metric.WithReader(exporter))
	provider.SetAsGlobal()
	defer provider.Shutdown(ctx)

	// Counter.
	counter.Inc(ctx)
	counter.Add(ctx, 10)

	// UpDownCounter.
	upDownCounter.Inc(ctx)
	upDownCounter.Add(ctx, 10)
	upDownCounter.Dec(ctx)

	// Record values for histogram.
	histogram.Record(1)
	histogram.Record(20)
	histogram.Record(30)
	histogram.Record(101)
	histogram.Record(2000)
	histogram.Record(9000)
	histogram.Record(20000)

	// HTTP Server for metrics exporting.
	s := g.Server()
	s.BindHandler("/metrics", ghttp.WrapH(promhttp.Handler()))
	s.SetPort(8000)
	s.Run()
}

```

--------------------------------

### File Header Comment Example

Source: https://github.com/gogf/gf/blob/master/AGENTS.md

A file-purpose comment should be placed immediately before the package declaration in a Go source file.

```go
// Package plugin implements plugin manifest discovery, lifecycle orchestration,
// governance metadata synchronization, and host integration for LinaPro plugins.
package plugin
```

--------------------------------

### TCPServer Method Signatures

Source: https://github.com/gogf/gf/wiki/网络服务开发/TCPServer

Lists the available methods for the TCPServer. These include functions to get or create a server instance, and methods to configure and run the server.

```go
func GetServer(names ...string) *Server
func NewServer(address string, handler func(net.Conn), names ...string) *Server
func (s *Server) Run() error
func (s *Server) SetAddress(address string)
func (s *Server) SetHandler(handler func(net.Conn))
```

--------------------------------

### Modify Configuration Directory via Environment Variable

Source: https://github.com/gogf/gf/wiki/Web服务开发/配置管理

Example of how to specify a custom configuration directory using an environment variable.

```shell
cfgpath=/opt/config/; ./main
```

--------------------------------

### Example: Sending a POST Request

Source: https://github.com/gogf/gf/wiki/功能模块设计/HTTP客户端

Illustrates sending a POST request with form data using the standalone ghttp.Post function and handling the response.

```go
package main

import (
	"fmt"
	"gitee.com/johng/gf/g/net/ghttp"
)

func main() {
	if r, e := ghttp.Post("http://127.0.0.1:8199/form", "name=john&age=18"); e != nil {
		fmt.Println(e)
	} else {
		fmt.Println(string(r.ReadAll()))
		r.Close()
	}
}
```

--------------------------------

### Setting a Routing Rule for Pseudo-Static Links

Source: https://github.com/gogf/gf/wiki/Web服务开发/路由控制

Demonstrates how to convert a pseudo-static URL pattern to a standard GET parameter URL using SetRule. This is useful for making URLs more user-friendly and SEO-compatible. Ensure the regular expression correctly captures and replaces URL segments.

```go
package demo

import "gitee.com/johng/gf/g/net/ghttp"

func init() {
    ghttp.GetServer().BindHandler("/list", List)
    ghttp.GetServer().Router.SetRule(`\/list\/page\/(\d+)[\/\?]*`, "/list?page=$1&")
}

func List(r *ghttp.Request) {
    r.Response.WriteString("list page:" + r.GetQueryString("page"))
}
```

--------------------------------

### Manage Dockerized Services

Source: https://github.com/gogf/gf/blob/master/AGENTS.md

Commands to manage the local Docker stack for testing backing services like MySQL. Use 'make docker' to start the default stack or specify services.

```bash
make docker
```

```bash
make docker cmd=start svc=mysql
```

```bash
make docker cmd=stop  svc=mysql
```

--------------------------------

### File Upload Handler Example

Source: https://github.com/gogf/gf/wiki/Web服务开发/输入输出

Demonstrates how to handle file uploads in a web server using the ghttp.Request. It saves the uploaded file to the server's temporary directory and ensures the file pointer is closed.

```go
package demo

import (
    "gitee.com/johng/gf/g/os/gfile"
    "gitee.com/johng/gf/g/net/ghttp"
)

func Upload(r *ghttp.Request) {
    if f, h, e := r.FormFile("upload-file"); e == nil {
        defer f.Close()
        fname  := gfile.Basename(h.Filename)
        buffer := make([]byte, h.Size)
        f.Read(buffer)
        gfile.PutBinContents("/tmp/" + fname, buffer)
        r.Response.WriteString(fname + " uploaded successly")
    } else {
        r.Response.WriteString(e.Error())
    }
}

func UploadShow(r *ghttp.Request) {
    r.Response.WriteString(`
<html>
<head>
    <title>上传文件</title>
</head>
    <body>
        <form enctype="multipart/form-data" action="/upload" method="post">
            <input type="file" name="upload-file" />
            <input type="submit" value="upload" />
        </form>
    </body>
</html>
`)
}

func init() {
    ghttp.GetServer().BindHandler("/upload",      Upload)
    ghttp.GetServer().BindHandler("/upload/show", UploadShow)
}
```

--------------------------------

### Web Server Initialization and Service Registration

Source: https://github.com/gogf/gf/wiki/Web服务开发/服务注册

Illustrates how to initialize the ghttp server and run it, with service registrations typically handled in the package's init() function. It shows importing a package that contains its own service registrations.

```go
package main

import (
    "gitee.com/johng/gf/g/net/ghttp"
    _ "gitee.com/johng/gf/geg/frame/mvc/controller/demo"
)

func main() {
    ghttp.GetServer().SetPort(8199)
    ghttp.GetServer().Run()
}
```

--------------------------------

### Registering a Callback Function for "Hello World"

Source: https://github.com/gogf/gf/wiki/Web服务开发/服务注册

Demonstrates the simplest service registration using BindHandler to associate a URI with a callback function. The callback receives a ghttp.Request object for handling request parameters and returning responses.

```go
package main

import "gitee.com/johng/gf/g/net/ghttp"

func init() {
    ghttp.GetServer().BindHandler("/", func(r *ghttp.Request) {
        r.Response.WriteString("Hello World!")
    })
}
```

--------------------------------

### Setting a Routing Rule for Content Patching

Source: https://github.com/gogf/gf/wiki/Web服务开发/路由控制

Demonstrates how to use SetPatchRule to automatically convert specific URL patterns within response content to a different format, typically for pseudo-static links. This simplifies output formatting by handling replacements globally. The example converts a dynamic link to a pseudo-static one.

```go
package demo

import "gitee.com/johng/gf/g/net/ghttp"

func init() {
    ghttp.GetServer().BindHandler("/router-patch", RouterPatch)
    ghttp.GetServer().Router.SetPatchRule(`\/list\?page=(\d+)&*`, "/list/page/$1?")
}

func RouterPatch(r *ghttp.Request) {
    r.Response.WriteString(`<a href="/list?page=2&ajax=1">page2</a>`)
}
```

--------------------------------

### Importing Package for Automatic Service Registration

Source: https://github.com/gogf/gf/wiki/Web服务开发/服务注册

Demonstrates using a blank import to include a package that contains its own service registration logic within its init() function. This allows for modular registration of controllers, objects, and handlers.

```go
import _ "gitee.com/johng/gf/geg/frame/mvc/controller/demo"
```

--------------------------------

### Install GoFrame Nacos Registry

Source: https://github.com/gogf/gf/blob/master/contrib/registry/nacos/README.MD

Install the nacos registry component for GoFrame. It is recommended to use go.mod for managing dependencies.

```go
go get -u -v github.com/gogf/gf/contrib/registry/nacos/v2
```

```go
require github.com/gogf/gf/contrib/ અ/registry/nacos/v2 latest
```

--------------------------------

### Create Custom Boot Package for Apollo

Source: https://github.com/gogf/gf/blob/master/contrib/config/apollo/README.MD

Create a custom boot package to initialize the Apollo adapter for global configuration. This should be imported early in your application.

```go
package boot

import (
	"github.com/gogf/gf/contrib/config/apollo/v2"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gctx"
)

func init() {
	var (
		ctx     = gctx.GetInitCtx()
		appId   = "SampleApp"
		cluster = "default"
		ip      = "http://localhost:8080"
	)
	// Create apollo Client that implements gcfg.Adapter.
	adapter, err := apollo.New(ctx, apollo.Config{
		AppID:   appId,
		IP:      ip,
		Cluster: cluster,
	})
	if err != nil {
		g.Log().Fatalf(ctx, `%+v`, err)
	}
	// Change the adapter of default configuration instance.
	g.Cfg().SetAdapter(adapter)
}
```

--------------------------------

### Generate and Use RSA Key Pair with PKCS#1 v1.5 Padding

Source: https://github.com/gogf/gf/blob/master/crypto/grsa/README.md

Illustrates generating a default RSA key pair and performing encryption and decryption using the legacy PKCS#1 v1.5 padding scheme. Use this only for backward compatibility.

```go
package main

import (
    "fmt"
    "github.com/gogf/gf/v2/crypto/grsa"
)

func main() {
    // Generate a default RSA key pair (2048 bits)
    privateKey, publicKey, err := grsa.GenerateDefaultKeyPair()
    if err != nil {
        panic(err)
    }

    // Data to encrypt
    plainText := []byte("Hello, World!")

    // Encrypt with public key (PKCS#1 v1.5 - legacy)
    cipherText, err := grsa.Encrypt(plainText, publicKey)
    if err != nil {
        panic(err)
    }

    // Decrypt with private key
    decryptedText, err := grsa.Decrypt(cipherText, privateKey)
    if err != nil {
        panic(err)
    }

    fmt.Println(string(decryptedText)) // Output: Hello, World!
}
```

--------------------------------

### Using Default Goroutine Pool with Size Limit

Source: https://github.com/gogf/gf/wiki/功能模块设计/Goroutine池

Demonstrates how to set the size of the default goroutine pool and add tasks. It also shows how to monitor the pool's size and pending jobs using gtime.SetInterval.

```go
package main

import (
    "time"
    "fmt"
    "gitee.com/johng/gf/g/os/gtime"
    "gitee.com/johng/gf/g/os/grpool"
)

func job() {
    time.Sleep(1*time.Second)
}

func main() {
    grpool.SetSize(10)
    for i := 0; i < 1000; i++ {
        grpool.Add(job)
    }
    gtime.SetInterval(2*time.Second, func() bool {
        fmt.Println("size:", grpool.Size())
        fmt.Println("jobs:", grpool.Jobs())
        return true
    })
    select {}
}
```

--------------------------------

### Basic Syntax and Variable Access

Source: https://github.com/gogf/gf/wiki/Web服务开发/模板引擎

Demonstrates basic template syntax using {{}} for tags, '.' for object values, and '$' for context variables. Supports standard strings, raw strings, and bytes.

```GoTemplate
{{"string"}}
{{`raw string`}}
{{'c'}}
{{print nil}}
```

--------------------------------

### Import Boot Package in Main Application

Source: https://github.com/gogf/gf/blob/master/contrib/config/kubecm/README.MD

Import the custom boot package at the top of your main.go file to ensure configurations are loaded before other packages.

```go
package main

import (
	_ "github.com/gogf/gf/example/config/kubecm/boot_in_pod"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gctx"
)

func main() {
	var ctx = gctx.GetInitCtx()

	// Available checks.
	g.Dump(g.Cfg().Available(ctx))

	// All key-value configurations.
	g.Dump(g.Cfg().Data(ctx))

	// Retrieve certain value by key.
	g.Dump(g.Cfg().MustGet(ctx, "server.address"))
}
```

--------------------------------

### GF genv Module: Environment Variable Functions

Source: https://github.com/gogf/gf/wiki/功能模块设计/环境变量模块

Provides common functions for interacting with environment variables. Use `Get` to retrieve a variable, `Set` to set one, `Remove` to delete one, and `All` to get all variables.

```go
func All() []string
func Get(k string) string
func Remove(k string) error
func Set(k, v string) error
```

--------------------------------

### Date and Time Retrieval

Source: https://github.com/gogf/gf/wiki/功能模块设计/时间模块

Functions to get the current date and time in different formats.

```APIDOC
## Date()

### Description
Retrieves the current date as a string.

### Method
```go
func Date() string
```

## Datetime()

### Description
Retrieves the current date and time as a string.

### Method
```go
func Datetime() string
```
```

--------------------------------

### Example: Sending a DELETE Request

Source: https://github.com/gogf/gf/wiki/功能模块设计/HTTP客户端

Demonstrates sending a DELETE request using the standalone ghttp.Delete function.

```go
package main

import (
	"fmt"
	"gitee.com/johng/gf/g/net/ghttp"
)

func main() {
	if r, e := ghttp.Delete("http://127.0.0.1:8199/user", "10000"); e != nil {
		fmt.Println(e)
	} else {
		fmt.Println(string(r.ReadAll()))
		r.Close()
	}
}
```

--------------------------------

### Get Array by Pattern

Source: https://github.com/gogf/gf/wiki/功能模块设计/数据编码解析

Retrieves a value as a slice of interfaces from the Parser using a hierarchical pattern string.

```go
func (p *Parser) GetArray(pattern string) []interface{}
```

--------------------------------

### Get Map by Pattern

Source: https://github.com/gogf/gf/wiki/功能模块设计/数据编码解析

Retrieves a map[string]interface{} value from the Parser using a hierarchical pattern string.

```go
func (p *Parser) GetMap(pattern string) map[string]interface{}
```

--------------------------------

### Get Command-Line Arguments by Index

Source: https://github.com/gogf/gf/wiki/功能模块设计/命令行模块

Retrieve command-line arguments using their zero-based index. Useful for positional arguments.

```go
gcmd.Value.Get(0)
```

```go
gcmd.Value.Get(1)
```

--------------------------------

### Build and Test Root Module

Source: https://github.com/gogf/gf/blob/master/AGENTS.md

Build all packages in the root module and run tests with race detection enabled. Use these commands from the root of the repository.

```bash
go build ./...
```

```bash
go test ./... -count=1 -race
```

--------------------------------

### Create Custom Boot Package for Polaris Config

Source: https://github.com/gogf/gf/blob/master/contrib/config/polaris/README.MD

Set up a custom boot package to initialize the Polaris configuration adapter globally. This ensures configuration is loaded from Polaris before other packages initialize.

```go
package boot

import (
    "github.com/gogf/gf/contrib/config/polaris/v2"
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/os/gctx"
)

func init() {
    var (
        ctx       = gctx.GetInitCtx()
        namespace = "default"
        fileGroup = "goframe"
        fileName  = "config.yaml"
        path      = "testdata/polaris.yaml"
        logDir    = "/tmp/polaris/log"
    )
    // Create polaris Client that implements gcfg.Adapter.
    adapter, err := polaris.New(ctx, polaris.Config{
        Namespace: namespace,
        FileGroup: fileGroup,
        FileName:  fileName,
        Path:      path,
        LogDir:    logDir,
        Watch:     true,
    })
    if err != nil {
        g.Log().Fatalf(ctx, `%+v`, err)
    }
    // Change the adapter of default configuration instance.
    g.Cfg().SetAdapter(adapter)
}
```

--------------------------------

### Import PostgreSQL Driver

Source: https://github.com/gogf/gf/blob/master/contrib/drivers/README.MD

Import the PostgreSQL driver to enable gdb to connect to PostgreSQL databases.

```go
import _ "github.com/gogf/gf/contrib/drivers/pgsql/v2"
```

--------------------------------

### Get Value by Pattern

Source: https://github.com/gogf/gf/wiki/功能模块设计/数据编码解析

Retrieves a value from the Parser using a hierarchical pattern string. The pattern uses '.' to separate levels.

```go
func (p *Parser) Get(pattern string) interface{}
```

--------------------------------

### Manage Specific Docker Service

Source: https://github.com/gogf/gf/blob/master/CLAUDE.md

Starts or stops a specific backing service (e.g., mysql) within the local Docker stack.

```bash
make docker cmd=start svc=mysql
```

```bash
make docker cmd=stop  svc=mysql
```

--------------------------------

### HTTP Server with Consul Registry

Source: https://github.com/gogf/gf/blob/master/contrib/registry/consul/README.MD

Example of an HTTP server registering itself with Consul. Ensure Consul is running and accessible at the specified address.

```go
package main

import (
    "context"
    
    "github.com/gogf/gf/contrib/registry/consul/v2"
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/net/ghttp"
    "github.com/gogf/gf/v2/net/gsvc"
)

func main() {
    registry, err := consul.New(consul.WithAddress("127.0.0.1:8500"))
    if err != nil {
        g.Log().Fatal(context.Background(), err)
    }
    gsvc.SetRegistry(registry)

    s := g.Server("hello.svc")
    s.BindHandler("/", func(r *ghttp.Request) {
        g.Log().Info(r.Context(), "request received")
        r.Response.Write("Hello world")
    })
    s.Run()
}
```

--------------------------------

### gf CLI Help

Source: https://github.com/gogf/gf/blob/master/cmd/gf/README.MD

Displays the help information for the gf CLI tool, outlining available commands and options.

```shell
$ gf -h
USAGE
    gf COMMAND [OPTION]

COMMAND
    up         upgrade GoFrame version/tool to latest one in current project
    env        show current Golang environment variables
    fix        auto fixing codes after upgrading to new GoFrame version
    run        running go codes with hot-compiled-like feature
    gen        automatically generate go files for dao/do/entity/pb/pbentity
    tpl        template parsing and building commands
    init       create and initialize an empty GoFrame project
    pack       packing any file/directory to a resource file, or a go file
    build      cross-building go project for lots of platforms
    docker     build docker image for current GoFrame project
    install    install gf binary to system (might need root/admin permission)
    version    show version information of current binary
    doc        download https://pages.goframe.org/ to run locally

OPTION
    -y, --yes       all yes for all command without prompt ask
    -v, --version   show version information of current binary
    -d, --debug     show internal detailed debugging information
    -h, --help      more information about this command

ADDITIONAL
    Use "gf COMMAND -h" for details about a command.
```

--------------------------------

### Using Parentheses for Function Arguments

Source: https://github.com/gogf/gf/wiki/Web服务开发/模板引擎

Shows how to nest function calls, using the output of one function as an argument to another, similar to `fmt.Sprintf`.

```go
{{printf "nums is %s %d" (printf "%d %d" 1 2) 3}}
```

--------------------------------

### Get Integer by Pattern

Source: https://github.com/gogf/gf/wiki/功能模块设计/数据编码解析

Retrieves an integer value from the Parser using a hierarchical pattern string. Returns 0 if the value is not an integer or cannot be converted.

```go
func (p *Parser) GetInt(pattern string) int
```

--------------------------------

### Read Database Host Configuration

Source: https://github.com/gogf/gf/wiki/Web服务开发/配置管理

Demonstrates reading a specific configuration value (database host) from the global configuration using hierarchical access.

```go
package demo

import (
    "gitee.com/johng/gf/g/net/ghttp"
    "gitee.com/johng/gf/g/frame/gins"
)

func init() {
    ghttp.GetServer().BindHandler("/config", func (r *ghttp.Request) {
        r.Response.WriteString(gins.Config().GetString("database.default.0.host"))
    })
}
```

--------------------------------

### Get Float64 by Pattern

Source: https://github.com/gogf/gf/wiki/功能模块设计/数据编码解析

Retrieves a float64 value from the Parser using a hierarchical pattern string. Returns 0.0 if the value is not a float64 or cannot be converted.

```go
func (p *Parser) GetFloat64(pattern string) float64
```

--------------------------------

### Get Float32 by Pattern

Source: https://github.com/gogf/gf/wiki/功能模块设计/数据编码解析

Retrieves a float32 value from the Parser using a hierarchical pattern string. Returns 0.0 if the value is not a float32 or cannot be converted.

```go
func (p *Parser) GetFloat32(pattern string) float32
```