Support mysql prepare statement command (elastic#8084)

This improves Packetbeat's mysql decoder to understand and report prepared statements.

```
  "query": "select distinct count(distinct purchasede0_.id) as col_0_0_ from purchase_demand purchasede0_ where purchasede0_.chain_master=? and purchasede0_.create_time>=? and purchasede0_.create_time<=?",
  "params": [
    "A1224638",
    "2017/7/28 0:0:0",
    "2017/10/28 23:59:59"
  ],
```

CHANGELOG.asciidoc

@@ -105,6 +105,8 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 
 *Packetbeat*
 
+- Add support to decode mysql prepare statement command. {pull}8084[8084]
+
 *Functionbeat*
 
 ==== Deprecated

packetbeat/_meta/beat.reference.yml

@@ -279,7 +279,7 @@ packetbeat.protocols:
 
   # Configure the ports where to listen for MySQL traffic. You can disable
   # the MySQL protocol by commenting out the list of ports.
-  ports: [3306]
+  ports: [3306,3307]
 
   # If this option is enabled, the raw message of the request (`request` field)
   # is sent to Elasticsearch. The default is false.

packetbeat/_meta/beat.yml

@@ -70,7 +70,7 @@ packetbeat.protocols:
 - type: mysql
   # Configure the ports where to listen for MySQL traffic. You can disable
   # the MySQL protocol by commenting out the list of ports.
-  ports: [3306]
+  ports: [3306,3307]
 
 - type: pgsql
   # Configure the ports where to listen for Pgsql traffic. You can disable

packetbeat/docs/gettingstarted.asciidoc

@@ -208,7 +208,7 @@ packetbeat.protocols:
   ports: [11211]
 
 - type: mysql
-  ports: [3306]
+  ports: [3306,3307]
 
 - type: pgsql
   ports: [5432]

packetbeat/docs/packetbeat-options.asciidoc

@@ -435,7 +435,7 @@ packetbeat.protocols:
   ports: [11211]
 
 - type: mysql
-  ports: [3306]
+  ports: [3306,3307]
 
 - type: redis
   ports: [6379]
@@ -899,22 +899,58 @@ The memcache protocol analyzer will wait for the number of milliseconds specifie
 `udptransactiontimeout` before publishing quiet messages. Non-quiet messages or
 quiet requests with an error response are published immediately.
 
-[[packetbeat-mysql-pgsql-options]]
-=== Capture MySQL and PgSQL traffic
+[[packetbeat-mysql-options]]
+=== Capture MySQL traffic
 
 ++++
-<titleabbrev>MySQL and PgSQL</titleabbrev>
+<titleabbrev>MySQL</titleabbrev>
 ++++
 
-The `mysql` and `pgsql` sections of the +{beatname_lc}.yml+ config file specify configuration options for the MySQL
-and PgSQL protocols.
+The `mysql` section of the +{beatname_lc}.yml+ config file specifies configuration
+options for the MySQL protocols.
 
 [source,yaml]
 ------------------------------------------------------------------------------
 packetbeat.protocols:
 
 - type: mysql
-  ports: [3306]
+  ports: [3306,3307]
+------------------------------------------------------------------------------
+
+==== Configuration options
+
+Also see <<common-protocol-options>>.
+
+===== `max_rows`
+
+The maximum number of rows from the SQL message to publish to Elasticsearch. The
+default is 10 rows.
+
+
+===== `max_row_length`
+
+The maximum length in bytes of a row from the SQL message to publish to
+Elasticsearch. The default is 1024 bytes.
+
+==== `statement_timeout`
+
+The duration for which prepared statements are cached after their last use.
+Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
+The default is `1h`.
+
+[[packetbeat-pgsql-options]]
+=== Capture PgSQL traffic
+
+++++
+<titleabbrev>PgSQL</titleabbrev>
+++++
+
+The `pgsql` sections of the +{beatname_lc}.yml+ config file specifies configuration
+options for the PgSQL protocols.
+
+[source,yaml]
+------------------------------------------------------------------------------
+packetbeat.protocols:
 
 - type: pgsql
   ports: [5432]

packetbeat/packetbeat.reference.yml

@@ -279,7 +279,7 @@ packetbeat.protocols:
 
   # Configure the ports where to listen for MySQL traffic. You can disable
   # the MySQL protocol by commenting out the list of ports.
-  ports: [3306]
+  ports: [3306,3307]
 
   # If this option is enabled, the raw message of the request (`request` field)
   # is sent to Elasticsearch. The default is false.

packetbeat/packetbeat.yml

@@ -70,7 +70,7 @@ packetbeat.protocols:
 - type: mysql
   # Configure the ports where to listen for MySQL traffic. You can disable
   # the MySQL protocol by commenting out the list of ports.
-  ports: [3306]
+  ports: [3306,3307]
 
 - type: pgsql
   # Configure the ports where to listen for Pgsql traffic. You can disable

packetbeat/protos/mysql/config.go

@@ -18,22 +18,26 @@
 package mysql
 
 import (
+	"time"
+
 	"github.com/elastic/beats/packetbeat/config"
 	"github.com/elastic/beats/packetbeat/protos"
 )
 
 type mysqlConfig struct {
 	config.ProtocolCommon `config:",inline"`
-	MaxRowLength          int `config:"max_row_length"`
-	MaxRows               int `config:"max_rows"`
+	MaxRowLength          int           `config:"max_row_length"`
+	MaxRows               int           `config:"max_rows"`
+	StatementTimeout      time.Duration `config:"statement_timeout"`
 }
 
 var (
 	defaultConfig = mysqlConfig{
 		ProtocolCommon: config.ProtocolCommon{
 			TransactionTimeout: protos.DefaultTransactionExpiration,
 		},
-		MaxRowLength: 1024,
-		MaxRows:      10,
+		MaxRowLength:     1024,
+		MaxRows:          10,
+		StatementTimeout: 3600 * time.Second,
 	}
 )