cmd/statreceiver: allow for packet filtering to packet destinations (#2019)

What: allow packetfilter to work on packet destinations instead of only on metric destinations. this will allow us to filter what applications get sent to rothko.

Why: currently rothko is drowning in storj-sim data and it'd be nice to filter out.

cmd/statreceiver/example.lua

@@ -33,15 +33,10 @@ metric_handlers = mcopy(
 
 -- create a metric parser.
 metric_parser =
-  parse(  -- parse takes one or two arguments. the first argument is
-          -- a metric handler, the remaining one is a per-packet application or
-          -- instance filter. each filter is a regex. all packets must
-          -- match all packet filters.
-    sanitize(metric_handlers), -- sanitize converts weird chars to underscores
-    packetfilter("storagenode-prod|satellite-prod|uplink-prod", ""))
+  parse(sanitize(metric_handlers)) -- sanitize converts weird chars to underscores
 
 -- pcopy forks data to multiple outputs
--- output types include parse, fileout, and udpout
+-- output types include parse, fileout, packetfilter, and udpout
 destination = pcopy(
   fileout("dump.out"),
   metric_parser,
@@ -50,7 +45,8 @@ destination = pcopy(
   udpout("localhost:9001"),
 
   -- rothko
-  udpout("localhost:9002"))
+  packetfilter("storagenode-prod|satellite-prod|uplink-prod", "",
+    udpout("localhost:9002")))
 
 -- tie the source to the destination
 deliver(source, destination)

cmd/statreceiver/filter.go

@@ -5,29 +5,58 @@ package main
 
 import (
 	"regexp"
+	"sync"
 	"time"
+
+	"github.com/zeebo/admission/admproto"
+
+	"storj.io/storj/internal/memory"
 )
 
-// PacketFilter is used during Packet parsing to determine if the Packet should
-// continue to be parsed.
+// PacketFilter inspects a packet header to determine if it should be passed
+// through
 type PacketFilter struct {
 	application *regexp.Regexp
 	instance    *regexp.Regexp
+	dest        PacketDest
+	scratch     sync.Pool
 }
 
-// NewPacketFilter creates a PacketFilter. It takes an application regular
-// expression and an instance regular expression. If the regular expression
-// is matched, the packet will be parsed.
-func NewPacketFilter(applicationRegex, instanceRegex string) *PacketFilter {
+// NewPacketFilter creates a PacketFilter. It takes a packet destination,
+// an application regular expression, and an instance regular expression.
+// If the regular expression is matched, the packet will be passed through.
+func NewPacketFilter(applicationRegex, instanceRegex string, dest PacketDest) *PacketFilter {
 	return &PacketFilter{
 		application: regexp.MustCompile(applicationRegex),
 		instance:    regexp.MustCompile(instanceRegex),
+		dest:        dest,
+		scratch: sync.Pool{
+			New: func() interface{} {
+				var x [10 * memory.KB]byte
+				return &x
+			},
+		},
 	}
 }
 
-// Filter returns true if the application and instance match the filter.
-func (a *PacketFilter) Filter(application, instance string) bool {
-	return a.application.MatchString(application) && a.instance.MatchString(instance)
+// Packet passes the packet along to the given destination if the regexes pass
+func (a *PacketFilter) Packet(data []byte, ts time.Time) error {
+	cdata, err := admproto.CheckChecksum(data)
+	if err != nil {
+		return err
+	}
+	scratch := a.scratch.Get().(*[10 * memory.KB]byte)
+	defer a.scratch.Put(scratch)
+
+	r := admproto.NewReaderWith((*scratch)[:])
+	_, application, instance, err := r.Begin(cdata)
+	if err != nil {
+		return err
+	}
+	if a.application.Match(application) && a.instance.Match(instance) {
+		return a.dest.Packet(data, ts)
+	}
+	return nil
 }
 
 // KeyFilter is a MetricDest that only passes along metrics that pass the key

cmd/statreceiver/parser.go

@@ -9,28 +9,23 @@ import (
 	"time"
 
 	"github.com/zeebo/admission/admproto"
-)
 
-const (
-	kb = 1024
+	"storj.io/storj/internal/memory"
 )
 
 // Parser is a PacketDest that sends data to a MetricDest
 type Parser struct {
 	dest    MetricDest
-	filters []*PacketFilter
 	scratch sync.Pool
 }
 
-// NewParser creates a Parser. It sends metrics to dest, provided they pass all
-// of the provided PacketFilters
-func NewParser(dest MetricDest, filters ...*PacketFilter) *Parser {
+// NewParser creates a Parser. It sends metrics to dest.
+func NewParser(dest MetricDest) *Parser {
 	return &Parser{
-		dest:    dest,
-		filters: filters,
+		dest: dest,
 		scratch: sync.Pool{
 			New: func() interface{} {
-				var x [10 * kb]byte
+				var x [10 * memory.KB]byte
 				return &x
 			},
 		},
@@ -44,7 +39,7 @@ func (p *Parser) Packet(data []byte, ts time.Time) (err error) {
 		return err
 	}
 
-	scratch := p.scratch.Get().(*[10 * kb]byte)
+	scratch := p.scratch.Get().(*[10 * memory.KB]byte)
 	defer p.scratch.Put(scratch)
 
 	r := admproto.NewReaderWith((*scratch)[:])
@@ -54,12 +49,6 @@ func (p *Parser) Packet(data []byte, ts time.Time) (err error) {
 	}
 
 	app, inst := string(appb), string(instb)
-	for _, filter := range p.filters {
-		if !filter.Filter(app, inst) {
-			return nil
-		}
-	}
-
 	var key []byte
 	var value float64
 	for len(data) > 0 {