Initial extraction commit

1 files changed, 90 insertions, 0 deletions

diff --git a/service/app_runner.go b/service/app_runner.go
new file mode 100644
index 0000000..2aecf52
--- /dev/null
+++ b/service/app_runner.go
@@ -0,0 +1,90 @@
+package service
+
+import (
+        "context"
+        "os"
+        "os/signal"
+        "sync"
+        "syscall"
+)
+
+type AppRunnerLogger interface {
+        Info(...interface{})
+}
+
+type RunnerFunc func(context.Context, *sync.WaitGroup) error
+
+type AppRunner struct {
+        Logger         AppRunnerLogger
+        jobs           []RunnerFunc
+        backgroundJobs []RunnerFunc
+        wg             *sync.WaitGroup
+        sigs           chan os.Signal
+        ctx            context.Context
+        ctxCancel      context.CancelFunc
+}
+
+func NewAppRunner(ctx context.Context, logger AppRunnerLogger) *AppRunner {
+        r := &AppRunner{
+                jobs:           []RunnerFunc{},
+                backgroundJobs: []RunnerFunc{},
+                wg:             &sync.WaitGroup{},
+                sigs:           make(chan os.Signal),
+                Logger:         logger,
+        }
+
+        r.ctx, r.ctxCancel = context.WithCancel(ctx)
+
+        signal.Notify(r.sigs, os.Interrupt)
+        signal.Notify(r.sigs, os.Kill)
+        signal.Notify(r.sigs, syscall.SIGTERM)
+
+        return r
+}
+
+func (r *AppRunner) AddJob(f RunnerFunc) {
+        r.jobs = append(r.jobs, f)
+}
+
+func (r *AppRunner) AddBackgroundJob(f RunnerFunc) {
+        r.backgroundJobs = append(r.backgroundJobs, f)
+}
+
+func (r *AppRunner) goRunPanic(f func(context.Context, *sync.WaitGroup) error) {
+        errs := make(chan error)
+        go func() { errs <- f(r.ctx, r.wg) }()
+        select {
+        case e := <-errs:
+                panic(e)
+        default:
+        }
+}
+
+func (r *AppRunner) RunForever(enableBg bool) {
+        for _, f := range r.jobs {
+                r.goRunPanic(f)
+        }
+
+        if enableBg {
+                r.Logger.Info("Starting background jobs")
+                for _, f := range r.backgroundJobs {
+                        r.goRunPanic(f)
+                }
+        } else {
+                r.Logger.Info("Background jobs not enabled")
+        }
+
+        // go run foreground
+        // go run background if enabled
+        select {
+        case <-r.sigs:
+                r.Logger.Info("Shutting down main app context")
+                r.ctxCancel()
+
+                r.Logger.Info("Waiting for jobs to terminate")
+                r.wg.Wait()
+
+                r.Logger.Info("Shutdown completed")
+                return
+        }
+}