Close filebeat if prospector without paths exists

* Add test for harvesters

CHANGELOG.asciidoc

@@ -35,7 +35,7 @@ https://github.com/elastic/beats/compare/1.0.0...master[Check the HEAD diff]
 
 *Filebeat*
 - Add exclude_files configuration option {pull}563[563]
-- Stop filebeat if filebeat is started without any prospectors defined {pull}644[644]
+- Stop filebeat if filebeat is started without any prospectors defined or empty prospectors {pull}644[644] {pull}647[647]
 
 *Winlogbeat*
 

filebeat/crawler/prospector.go

@@ -60,6 +60,10 @@ func (p *Prospector) setupProspectorConfig() error {
 	// Init File Stat list
 	p.prospectorList = make(map[string]harvester.FileStat)
 
+	if config.Harvester.InputType == cfg.LogInputType && len(config.Paths) == 0 {
+		return fmt.Errorf("No paths were defined for prospector")
+	}
+
 	return nil
 }
 

filebeat/crawler/prospector_test.go

@@ -124,6 +124,7 @@ func TestProspectorInitInvalidIgnoreOlder(t *testing.T) {
 func TestProspectorInitInputTypeLog(t *testing.T) {
 
 	prospectorConfig := config.ProspectorConfig{
+		Paths: []string{"testpath1", "testpath2"},
 		Harvester: config.HarvesterConfig{
 			InputType: "log",
 		},
@@ -138,6 +139,23 @@ func TestProspectorInitInputTypeLog(t *testing.T) {
 	assert.Equal(t, "log", prospector.ProspectorConfig.Harvester.InputType)
 }
 
+func TestProspectorInitInputTypeLogError(t *testing.T) {
+
+	prospectorConfig := config.ProspectorConfig{
+		Harvester: config.HarvesterConfig{
+			InputType: "log",
+		},
+	}
+
+	prospector := Prospector{
+		ProspectorConfig: prospectorConfig,
+	}
+
+	err := prospector.Init()
+	// Error should be returned because no path is set
+	assert.Error(t, err)
+}
+
 func TestProspectorInitInputTypeStdin(t *testing.T) {
 
 	prospectorConfig := config.ProspectorConfig{

filebeat/tests/system/test_prospector.py

@@ -185,7 +185,7 @@ def test_rotating_ignore_older_low_write_rate(self):
         os.mkdir(self.working_dir + "/log/")
         testfile = self.working_dir + "/log/test.log"
 
-        proc = self.start_filebeat(debug_selectors=['*'])
+        filebeat = self.start_filebeat(debug_selectors=['*'])
 
         # wait for first  "Start next scan" log message
         self.wait_until(
@@ -230,14 +230,17 @@ def test_rotating_ignore_older_low_write_rate(self):
             lambda: self.output_count(lambda x: x >= lines),
             max_timeout=5)
 
-        proc.kill_and_wait()
+        filebeat.kill_and_wait()
 
     def test_shutdown_no_prospectors(self):
+        """
+        In case no prospectors are defined, filebeat must shut down and report an error
+        """
         self.render_config_template(
                 prospectors=False,
         )
 
-        proc = self.start_filebeat(debug_selectors=['*'])
+        filebeat = self.start_filebeat(debug_selectors=['*'])
 
         # wait for first  "Start next scan" log message
         self.wait_until(
@@ -249,3 +252,60 @@ def test_shutdown_no_prospectors(self):
             lambda: self.log_contains(
                  "shutting down"),
             max_timeout=10)
+
+        filebeat.kill_and_wait()
+
+
+    def test_no_paths_defined(self):
+        """
+        In case a prospector is defined but doesn't contain any paths, prospector must return error which
+        leads to shutdown of filebeat because of configuration error
+        """
+        self.render_config_template(
+        )
+
+        filebeat = self.start_filebeat(debug_selectors=['*'])
+
+        # wait for first  "Start next scan" log message
+        self.wait_until(
+                lambda: self.log_contains(
+                        "No paths were defined for prospector"),
+                max_timeout=10)
+
+        self.wait_until(
+                lambda: self.log_contains(
+                        "shutting down"),
+                max_timeout=10)
+
+        filebeat.kill_and_wait()
+
+
+    def test_files_added_late(self):
+        """
+        Tests that prospectors stay running even though no harvesters are started yet
+        """
+        self.render_config_template(
+                path=os.path.abspath(self.working_dir) + "/log/*",
+        )
+
+        os.mkdir(self.working_dir + "/log/")
+
+        filebeat = self.start_filebeat(debug_selectors=['*'])
+
+        # wait until events are sent for the first time
+        self.wait_until(
+                lambda: self.log_contains(
+                        "Events flushed"),
+                max_timeout=10)
+
+        testfile = self.working_dir + "/log/test.log"
+        with open(testfile, 'a') as file:
+            file.write("Hello World1\n")
+            file.write("Hello World2\n")
+
+        # wait for log to be read
+        self.wait_until(
+                lambda: self.output_has(lines=2),
+                max_timeout=15)
+
+        filebeat.kill_and_wait()