copy ECS fields where required

Elasticsearch aliases are leveraged for ECS compatibility wherever
possible.  Where that's not possible, values are written to both the
original location and the one ECS dictates. Here:

* copy context.tags to labels - object fields can't be aliased
* cast & copy context.request.url.port to url.port - keyword -> int
* copy context.request.url.protocol to url.scheme - trim the final :

Author: graphaelli

docs/data/elasticsearch/error.json

@@ -243,11 +243,18 @@
             ]
         }
     },
+    "labels": {
+        "organization_uuid": "9f0e9d64-c185-4d21-a6f4-4673ed561ec8"
+    },
     "processor": {
         "event": "error",
         "name": "error"
     },
     "transaction": {
         "id": "945254c5-67a5-417e-8a4e-aa29efcbfb79"
+    },
+    "url": {
+        "port": 8080,
+        "scheme": "https"
     }
 }

docs/data/elasticsearch/generated/errors.json

@@ -247,12 +247,19 @@
                     ]
                 }
             },
+            "labels": {
+                "organization_uuid": "9f0e9d64-c185-4d21-a6f4-4673ed561ec8"
+            },
             "processor": {
                 "event": "error",
                 "name": "error"
             },
             "timestamp": {
                 "us": 1494342245999999
+            },
+            "url": {
+                "port": 8080,
+                "scheme": "https"
             }
         },
         {

docs/data/elasticsearch/generated/metricsets.json

@@ -30,6 +30,10 @@
             "double_gauge": 3.141592653589793,
             "float_gauge": 9.16,
             "integer_gauge": 42767,
+            "labels": {
+                "code": "200",
+                "some.other.code": "abc"
+            },
             "long_gauge": 3147483648,
             "negative": {
                 "d": {

docs/data/elasticsearch/generated/spans.json

@@ -93,6 +93,9 @@
                     "tag1": "value1"
                 }
             },
+            "labels": {
+                "tag1": "value1"
+            },
             "parent": {
                 "id": "abcdefabcdef7890"
             },

docs/data/elasticsearch/generated/transactions.json

@@ -176,6 +176,9 @@
                     "username": "foo"
                 }
             },
+            "labels": {
+                "organization_uuid": "9f0e9d64-c185-4d21-a6f4-4673ed561ec8"
+            },
             "processor": {
                 "event": "transaction",
                 "name": "transaction"
@@ -198,6 +201,10 @@
                     "started": 17
                 },
                 "type": "request"
+            },
+            "url": {
+                "port": 8080,
+                "scheme": "https"
             }
         },
         {

docs/data/elasticsearch/metric.json

@@ -43,6 +43,10 @@
     "double_gauge": 3.141592653589793,
     "float_gauge": 9.16,
     "integer_gauge": 42767,
+    "labels": {
+        "code": "200",
+        "some.other.code": "abc"
+    },
     "long_gauge": 3147483648,
     "negative": {
         "d": {

docs/data/elasticsearch/span.json

@@ -22,6 +22,9 @@
             "span_tag": "something"
         }
     },
+    "labels": {
+        "span_tag": "something"
+    },
     "processor": {
         "event": "span",
         "name": "transaction"

docs/data/elasticsearch/transaction.json

@@ -107,6 +107,9 @@
             "username": "foo"
         }
     },
+    "labels": {
+        "organization_uuid": "9f0e9d64-c185-4d21-a6f4-4673ed561ec8"
+    },
     "processor": {
         "event": "transaction",
         "name": "transaction"
@@ -135,5 +138,9 @@
             }
         },
         "type": "request"
+    },
+    "url": {
+        "port": 8080,
+        "scheme": "https"
     }
 }

model/ecs.go

@@ -0,0 +1,54 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package model
+
+import (
+	"strconv"
+	"strings"
+
+	"github.com/elastic/apm-server/utility"
+	"github.com/elastic/beats/libbeat/common"
+)
+
+func CopyECS(fields common.MapStr) {
+	// context.tags -> labels
+	utility.Add(fields, "labels", fields["context"].(common.MapStr)["tags"])
+
+	// context.request.url.protocol -> url.scheme (minus trailing colon)
+	if scheme, err := fields.GetValue("context.request.url.protocol"); err == nil {
+		if schemeStr, ok := scheme.(string); ok {
+			utility.MergeAdd(fields, "url", common.MapStr{"scheme": strings.TrimSuffix(schemeStr, ":")})
+		}
+	}
+
+	// context.request.url.port -> url.port (as int)
+	if port, err := fields.GetValue("context.request.url.port"); err == nil {
+		if portStr, ok := port.(string); ok {
+			if portNum, err := strconv.Atoi(portStr); err == nil {
+				utility.MergeAdd(fields, "url", common.MapStr{"port": portNum})
+			}
+		}
+	}
+
+	// docker.container.labels -> container.labels
+	if containerLabels, err := fields.GetValue("docker.container.labels"); err == nil {
+		if containerLabelsMap, ok := containerLabels.(common.MapStr); ok {
+			utility.MergeAdd(fields, "container", common.MapStr{"labels": containerLabelsMap})
+		}
+	}
+}

model/error/event.go

@@ -198,6 +198,8 @@ func (e *Event) Transform(tctx *transform.Context) []beat.Event {
 	utility.AddId(fields, "parent", e.ParentId)
 	utility.AddId(fields, "trace", e.TraceId)
 
+	m.CopyECS(fields)
+
 	if e.v2Event {
 		if e.Timestamp.IsZero() {
 			e.Timestamp = tctx.RequestTime