Golang合并yaml文件过程逐步讲解

name: test
image: tom.png
environment:
  os: linux
  group: admin
  user: testAdmin
limits:
  cpu: 4
  memory: 512M

type Spec struct {
	// Name: name of the function
	Name string `yaml:"name"`
	// Image: Docker image name of the function
	Image       string            `yaml:"image"`
	Environment map[string]string `yaml:"environment,omitempty"`
	// Limits for the function
	Limits *FunctionResources `yaml:"limits,omitempty"`
}
// FunctionResources Memory and CPU
type FunctionResources struct {
	Memory string ` yaml:"memory"`
	CPU    string ` yaml:"cpu"`
}

import (
    "fmt"
    "os"
	"Gopkg.in/yaml.v2"
)
func ReadYaml() {
	bytesOut, err := os.ReadFile("config.yaml")
	if err != nil {
		panic(err)
	}
	spec := Spec{}
	if err := yaml.Unmarshal(bytesOut, &spec); err != nil {
		panic(err)
	}
	fmt.Printf("Function name: %s\tImage: %s\tEnvs: %d\n", spec.Name, spec.Image,
		len(spec.Environment))
	fmt.Printf("Limists: %s, %s\n", spec.Limits.CPU, spec.Limits.Memory)
}

func WriteYaml() {
	spec := Spec{
		Image: "docker.io/functions/figlet:latest",
		Name:  "figlet",
	}
	bytesOut, err := yaml.Marshal(spec)
	if err != nil {
		panic(err)
	}
	err = os.WriteFile("figlet.yaml", bytesOut, os.ModePerm)
	if err != nil {
		panic(err)
	}
	fmt.Printf("Wrote: figlet.yaml. . OK. \n")
}

import "GitHub.com/imdario/mergo"
func MergeYaml() {
	base := Spec{
		Image:       "docker.io/functions/figlet:latest",
		Name:        "figlet",
		Environment: map[string]string{"stage": "develop"},
		Limits:      &FunctionResources{Memory: "512Mi", CPU: "60Mi"},
	}
	production := Spec{
		Environment: map[string]string{"stage": "production"},
		Limits:      &FunctionResources{Memory: "1Gi", CPU: "100Mi"},
	}
	overrides := []Spec{
		base,
		production,
	}
	merged := Spec{}
	for _, override := range overrides {
		err := mergo.Merge(&merged, override, mergo.WithOverride)
		if err != nil {
			panic(err)
		}
	}
	bytesOut, err := yaml.Marshal(merged)
	if err != nil {
		panic(err)
	}
	fmt.Printf("Merged content: \n\n%s\n", string(bytesOut))
}