Handle the SIGINT and SIGTERM signals to support stopping a test cleanly (#84)

ooni.go

@@ -3,6 +3,7 @@ package ooni
 import (
 	"io/ioutil"
 	"os"
+	"sync/atomic"
 
 	"github.com/apex/log"
 	"github.com/ooni/probe-cli/config"
@@ -29,6 +30,10 @@ type Context struct {
 
 	dbPath     string
 	configPath string
+
+	// We need to use a int64 in order to use the atomic.AddInt64/LoadInt64
+	// operations to ensure consistent reads of the variables.
+	isTerminatedAtomicInt int64
 }
 
 // MaybeLocationLookup will lookup the location of the user unless it's already cached
@@ -36,6 +41,17 @@ func (c *Context) MaybeLocationLookup() error {
 	return c.Session.MaybeLookupLocation()
 }
 
+// IsTerminated checks to see if the isTerminatedAtomicInt is set to a non zero
+// value and therefore we have received the signal to shutdown the running test
+func (c *Context) IsTerminated() bool {
+	i := atomic.LoadInt64(&c.isTerminatedAtomicInt)
+	return i != 0
+}
+
+func (c *Context) Terminate() {
+	atomic.AddInt64(&c.isTerminatedAtomicInt, 1)
+}
+
 // Init the OONI manager
 func (c *Context) Init() error {
 	var err error
@@ -94,9 +110,10 @@ func (c *Context) Init() error {
 // NewContext creates a new context instance.
 func NewContext(configPath string, homePath string) *Context {
 	return &Context{
-		Home:       homePath,
-		Config:     &config.Config{},
-		configPath: configPath,
+		Home:                  homePath,
+		Config:                &config.Config{},
+		configPath:            configPath,
+		isTerminatedAtomicInt: 0,
 	}
 }