metricator/internal/application/application.go

79 lines
1.8 KiB
Go

package application
import (
"context"
"log"
"net/http"
"sync"
"go.dev.pztrn.name/metricator/internal/common"
"go.dev.pztrn.name/metricator/internal/storage"
"go.dev.pztrn.name/metricator/internal/storage/memory"
)
// Application is a thing that responsible for all application-related
// actions like data fetching, storing, etc. on higher level.
type Application struct {
config *Config
ctx context.Context
doneChan chan struct{}
name string
storage storage.Metrics
storageDone chan struct{}
fetchIsRunning bool
fetchIsRunningMutex sync.RWMutex
httpClient *http.Client
}
// NewApplication creates new application.
func NewApplication(ctx context.Context, name string, config *Config) *Application {
a := &Application{
config: config,
ctx: ctx,
doneChan: make(chan struct{}),
name: name,
}
a.initialize()
return a
}
// GetDoneChan returns a channel which should be used to block execution until
// application's routines are completed.
func (a *Application) GetDoneChan() chan struct{} {
return a.doneChan
}
// GetHandler returns HTTP requests handling function.
func (a *Application) GetHandler() common.HTTPHandlerFunc {
return a.respond
}
// Initializes internal things like storage, HTTP client, etc.
func (a *Application) initialize() {
a.storage, a.storageDone = memory.NewStorage(a.ctx, a.name+" storage")
log.Printf("Application '%s' initialized with configuration: %+v\n", a.name, a.config)
}
// Start starts asynchronous things like data fetching, storage cleanup, etc.
func (a *Application) Start() {
a.storage.Start()
go a.startFetcher()
// The Context Listening Goroutine.
go func() {
<-a.ctx.Done()
// We should wait until storage routines are also stopped.
<-a.storage.GetDoneChan()
log.Println("Application", a.name, "stopped")
a.doneChan <- struct{}{}
}()
}