Metricbeat: Support multiple apache versions

Apache before version 2.4.16 had less information in its status
page. Add support to both, old and new status pages.

CHANGELOG.asciidoc

@@ -66,6 +66,7 @@ https://github.com/elastic/beats/compare/v6.0.0-beta2...master[Check the HEAD di
 - Add filtering option by exact device names in system.diskio. `diskio.include_devices`. {pull}6085[6085]
 - Fix dealing with new process status codes in Linux kernel 4.14+. {pull}6306[6306]
 - Add config option for windows/perfmon metricset to ignore non existent counters. {pull}6432[6432]
+- Support apache status pages for versions older than 2.4.16. {pull}6450[6450]
 
 *Packetbeat*
 

metricbeat/docker-compose.yml

@@ -45,6 +45,11 @@ services:
   apache:
     build: ./module/apache/_meta
 
+  apache_2_4_12:
+    build:
+      context: ./module/apache/_meta
+      dockerfile: Dockerfile.2.4.12
+
   ceph:
     build: ./module/ceph/_meta
 

metricbeat/docs/modules/apache.asciidoc

@@ -11,8 +11,8 @@ HTTPD] servers.
 [float]
 === Compatibility
 
-The Apache metricsets were tested with Apache 2.4.20 and are expected to work with all versions
->= 2.2.31 and >= 2.4.16.
+The Apache metricsets were tested with Apache 2.4.12 and 2.4.20 and are expected to work with
+all versions >= 2.2.31 and >= 2.4.16.
 
 
 [float]

metricbeat/module/apache/_meta/Dockerfile.2.4.12

@@ -0,0 +1,4 @@
+FROM httpd:2.4.12
+RUN apt-get update && apt-get install -y curl
+HEALTHCHECK --interval=1s --retries=90 CMD curl -f http://localhost
+COPY ./httpd.conf /usr/local/apache2/conf/httpd.conf

metricbeat/module/apache/_meta/docs.asciidoc

@@ -4,8 +4,8 @@ HTTPD] servers.
 [float]
 === Compatibility
 
-The Apache metricsets were tested with Apache 2.4.20 and are expected to work with all versions
->= 2.2.31 and >= 2.4.16.
+The Apache metricsets were tested with Apache 2.4.12 and 2.4.20 and are expected to work with
+all versions >= 2.2.31 and >= 2.4.16.
 
 
 [float]

metricbeat/module/apache/_meta/env

@@ -1,2 +1,3 @@
 APACHE_HOST=apache
+APACHE_OLD_HOST=apache_2_4_12
 APACHE_PORT=80

metricbeat/module/apache/status/data.go

@@ -51,8 +51,40 @@ var (
 			"15": c.Float("Load15", s.Optional),
 		},
 	}
+
+	// Schema used till apache 2.4.12
+	schemaOld = s.Schema{
+		"total_accesses":   c.Int("Total Accesses"),
+		"total_kbytes":     c.Int("Total kBytes"),
+		"requests_per_sec": c.Float("ReqPerSec", s.Optional),
+		"bytes_per_sec":    c.Float("BytesPerSec", s.Optional),
+		"workers": s.Object{
+			"busy": c.Int("BusyWorkers"),
+			"idle": c.Int("IdleWorkers"),
+		},
+		"uptime": s.Object{
+			"uptime": c.Int("Uptime"),
+		},
+		"connections": s.Object{
+			"total": c.Int("ConnsTotal", s.Optional),
+			"async": s.Object{
+				"writing":    c.Int("ConnsAsyncWriting", s.Optional),
+				"keep_alive": c.Int("ConnsAsyncKeepAlive", s.Optional),
+				"closing":    c.Int("ConnsAsyncClosing", s.Optional),
+			},
+		},
+	}
 )
 
+func applySchema(event common.MapStr, fullEvent map[string]interface{}) *s.Errors {
+	applicableSchema := schema
+	if _, found := fullEvent["ServerUptimeSeconds"]; !found {
+		applicableSchema = schemaOld
+	}
+	_, err := applicableSchema.ApplyTo(event, fullEvent)
+	return err
+}
+
 // Map body to MapStr
 func eventMapping(scanner *bufio.Scanner, hostname string) (common.MapStr, *s.Errors) {
 	var (
@@ -140,9 +172,8 @@ func eventMapping(scanner *bufio.Scanner, hostname string) (common.MapStr, *s.Er
 			"total":                  totalAll,
 		},
 	}
-	_, err := schema.ApplyTo(event, fullEvent)
 
-	return event, err
+	return event, applySchema(event, fullEvent)
 }
 
 /*

metricbeat/module/apache/status/status_test.go

@@ -123,8 +123,8 @@ func TestFetchEventContents(t *testing.T) {
 	assert.EqualValues(t, 63, event["total_kbytes"])
 
 	uptime := event["uptime"].(common.MapStr)
-	assert.EqualValues(t, 1026782, uptime["server_uptime"])
 	assert.EqualValues(t, 1026782, uptime["uptime"])
+	assert.EqualValues(t, 1026782, uptime["server_uptime"])
 }
 
 // TestFetchTimeout verifies that the HTTP request times out and an error is

metricbeat/tests/system/test_apache.py

@@ -7,13 +7,24 @@
 
 APACHE_FIELDS = metricbeat.COMMON_FIELDS + ["apache"]
 
-APACHE_STATUS_FIELDS = ["hostname", "total_accesses", "total_kbytes",
-                        "requests_per_sec", "bytes_per_sec", "bytes_per_request",
-                        "workers.busy", "workers.idle", "uptime", "cpu",
-                        "connections", "load", "scoreboard"]
+APACHE_STATUS_FIELDS = [
+    "hostname", "total_accesses", "total_kbytes",
+    "requests_per_sec", "bytes_per_sec", "bytes_per_request",
+    "workers.busy", "workers.idle", "uptime", "cpu",
+    "connections", "load", "scoreboard"
+]
 
-CPU_FIELDS = ["load", "user", "system", "children_user",
-              "children_system"]
+APACHE_OLD_STATUS_FIELDS = [
+    "hostname", "total_accesses", "total_kbytes",
+    "requests_per_sec", "bytes_per_sec",
+    "workers.busy", "workers.idle", "uptime",
+    "connections", "scoreboard"
+]
+
+
+CPU_FIELDS = [
+    "load", "user", "system", "children_user", "children_system"
+]
 
 
 class ApacheStatusTest(metricbeat.BaseTest):
@@ -37,7 +48,7 @@ def test_output(self):
 
         found = False
         # Waits until CPULoad is part of the status
-        while found == False:
+        while not found:
             res = urllib2.urlopen(hosts[0] + "/server-status?auto").read()
             if "CPULoad" in res:
                 found = True
@@ -52,16 +63,35 @@ def test_output(self):
         self.assertEqual(len(output), 1)
         evt = output[0]
 
-        # Verify the required fields are present.
-        self.assertItemsEqual(self.de_dot(APACHE_FIELDS), evt.keys())
-        apache_status = evt["apache"]["status"]
-        self.assertItemsEqual(self.de_dot(APACHE_STATUS_FIELDS), apache_status.keys())
-        self.assertItemsEqual(self.de_dot(CPU_FIELDS), apache_status["cpu"].keys())
-        # There are more fields that could be checked.
+        self.verify_fields(evt)
 
         # Verify all fields present are documented.
         self.assert_fields_are_documented(evt)
 
+    def verify_fields(self, evt):
+        self.assertItemsEqual(self.de_dot(APACHE_FIELDS), evt.keys())
+        apache_status = evt["apache"]["status"]
+        self.assertItemsEqual(
+            self.de_dot(APACHE_STATUS_FIELDS), apache_status.keys())
+        self.assertItemsEqual(
+            self.de_dot(CPU_FIELDS), apache_status["cpu"].keys())
+        # There are more fields that could be checked.
+
     def get_hosts(self):
         return ['http://' + os.getenv('APACHE_HOST', 'localhost') + ':' +
                 os.getenv('APACHE_PORT', '80')]
+
+
+class ApacheOldStatusTest(ApacheStatusTest):
+
+    COMPOSE_SERVICES = ['apache_2_4_12']
+
+    def verify_fields(self, evt):
+        self.assertItemsEqual(self.de_dot(APACHE_FIELDS), evt.keys())
+        apache_status = evt["apache"]["status"]
+        self.assertItemsEqual(
+            self.de_dot(APACHE_OLD_STATUS_FIELDS), apache_status.keys())
+
+    def get_hosts(self):
+        return ['http://' + os.getenv('APACHE_OLD_HOST', 'localhost') + ':' +
+                os.getenv('APACHE_PORT', '80')]