Add google chat to alert provider

[Hemaphat]

This PR was created by Google Jules and tested locally

This commit introduces a new alerting provider for Google Chat,
allowing you to receive incident notifications in your Google Chat spaces.

Key changes include:

• Addition of GoogleChatProvider in pkg/common/googlechat.go to handle
  message construction and sending via webhooks.
• A new message template config/googlechat_message.tmpl using Google Chat's
  Cards V2 format, adapted from the Slack template to support various
  alert sources and include an 'Acknowledge' button.
• Configuration updates in config/config.yaml and pkg/config/config.go
  to define settings for the Google Chat provider (webhook URL, template
  path, enable flag, message properties).
• Integration into pkg/common/factory_alert.go to make the Google Chat
  provider available.
• Documentation updates in README.md and src/userguide/configuration.md
  explaining how to configure and use the new integration.

This commit also includes:

• Implementation of a simple logger in pkg/utils/logger.go and refactoring
  of GoogleChatProvider to use this centralized logger.
• Addition of JSON helper functions (escapeJsonString, buildJsonArray,
  buildJsonObjectMembers) to pkg/utils/func_maps.go to ensure robust
  JSON generation in templates.
• Updates to unit tests to verify these new utility functions and logging.

[hoalongnatsu]

Hi @Hemaphat. Thank you for this PR. However, could you please show me an image of the Google Chat result? I have not used Google Chat before, so I am unsure how it looks with the template.

[hoalongnatsu]

Could you please review this pull request and test it? @nghiadaulau

[Hemaphat]

Hi @hoalongnatsu it look like this from example payload in readme.

[kai-vikki]

Could you please review this pull request and test it? @nghiadaulau

Oke, let's me check

[nghiadaulau]

Hi @Hemaphat
First of all, your google chat integration code seems to work quite well. It would be better if you take a screenshot of the result sent to Google Chat with a response example of a Grafana alert like the one I just sent. Please send it as a file (with a link attached) so that the admin can edit the README.

Next, I see you have implemented a logger in utils. I think the logger you should implement in the /pkg/logger folder.

In this folder, the interface for the logger will be implemented in a separate file. Then, other loggers will be created to implement the logger interface (There are many types of loggers such as Go's default logger, ZapLogger, GrayLogger,...)

Next I found in your logger you are using infoLogger: log.New(os.Stdout, "INFO: ", log.Ldate|log.Ltime|log.Lshortfile) this will show when the log line printed will always show where the log function is called instead of where you call the logger. For example when I call in cmd/main.go instead of logging to cmd/main.go it logs to logger. I think it is more efficient to use log.Llongfile.

I suggest you use zaplogger for better future.

Example interface:

package logger

type Fields = map[string]interface{}

type LogLevel int

const (
	LogLevelDebug LogLevel = iota
	LogLevelInfo
	LogLevelWarning
	LogLevelError
	LogLevelFatal
)

func (l LogLevel) String() string {
	switch l {
	case LogLevelDebug:
		return "debug"
	case LogLevelInfo:
		return "info"
	case LogLevelWarning:
		return "warning"
	case LogLevelError:
		return "error"
	case LogLevelFatal:
		return "fatal"
	default:
		return "info"
	}
}

type Logger interface {
	Debugf(message string, args ...interface{})
	Infof(message string, args ...interface{})
	Warnf(message string, args ...interface{})
	Errorf(message string, args ...interface{})
	Fatalf(message string, args ...interface{})
	// add more field to log
	With(key string, value interface{}) Logger
	Withs(Fields) Logger
	GetLevel() string
	Sync()
}

cc @hoalongnatsu

[nghiadaulau]

It's even better if when you init the logger, you can pass in the log level and enable, to control when to log the entire body and when not.

func New...(level LogLevel, enable bool) Logger {
///
...
}