Introspection types for core (#107)

go.mod

@@ -4,6 +4,7 @@ require (
 	github.com/btcsuite/btcd v0.20.1-beta
 	github.com/coreos/go-semver v0.3.0
 	github.com/gogo/protobuf v1.3.1
+	github.com/golang/protobuf v1.3.2
 	github.com/ipfs/go-cid v0.0.4
 	github.com/jbenet/goprocess v0.1.3
 	github.com/libp2p/go-flow-metrics v0.0.3

go.sum

@@ -34,7 +34,10 @@ github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6 h1:ZgQEtGgCBiWRM
 github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/golang/protobuf v1.3.2 h1:6nsPYzhq5kReh6QImI3k5qWzO4PEbvbIW2cwSfR/6xs=
+github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/google/go-cmp v0.3.0 h1:crn/baboCvb5fXaQ0IJ1SGTsTVrWpDsCWC8EGETZijY=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/gxed/hashland/keccakpg v0.0.1 h1:wrk3uMNaMxbXiHibbPO4S0ymqJMm41WiudyFSs7UnsU=

host/host.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/libp2p/go-libp2p-core/connmgr"
 	"github.com/libp2p/go-libp2p-core/event"
+	"github.com/libp2p/go-libp2p-core/introspect"
 	"github.com/libp2p/go-libp2p-core/network"
 	"github.com/libp2p/go-libp2p-core/peer"
 	"github.com/libp2p/go-libp2p-core/peerstore"
@@ -73,3 +74,14 @@ type Host interface {
 	// EventBus returns the hosts eventbus
 	EventBus() event.Bus
 }
+
+// IntrospectableHost is implemented by Host implementations that are
+// introspectable, that is, that expose an introspection server.
+type IntrospectableHost interface {
+
+	// Introspector returns the Introspector instance, with which the caller
+	// can:
+	//  - register data providers.
+	//  - fetch introspection data.
+	Introspector() introspect.Introspector
+}

introspect/doc.go

@@ -0,0 +1,9 @@
+// Package introspect is EXPERIMENTAL. It is subject to heavy change, and it
+// WILL change. For now, it is the simplest implementation to power the
+// proof-of-concept of the libp2p introspection framework.
+//
+// Package introspect contains the abstract skeleton of the introspection system
+// of go-libp2p. It holds the introspection data schema, and the primitives that
+// allow subsystems to register data providers, and clients to fetch the current
+// state of the system.
+package introspect

introspect/introspect.go

@@ -0,0 +1,25 @@
+package introspect
+
+import introspect_pb "github.com/libp2p/go-libp2p-core/introspect/pb"
+
+// ProtoVersion is the current version of the introspection protocol.
+const ProtoVersion uint32 = 1
+
+// EXPERIMENTAL. Introspector allows other sub-systems/modules to register
+// metrics/data providers AND also enables clients to fetch the current state of
+// the system.
+type Introspector interface {
+
+	// EXPERIMENTAL. RegisterDataProviders allows sub-systems/modules to
+	// register callbacks that supply introspection data.
+	RegisterDataProviders(p *DataProviders) error
+
+	// EXPERIMENTAL. FetchFullState returns the full state of the system, by
+	// calling all known data providers and returning a merged cross-cut of the
+	// running system.
+	FetchFullState() (*introspect_pb.State, error)
+
+	// EXPERIMENTAL. ListenAddrs returns the addresses on which the
+	// introspection server endpoint is listening for clients.
+	ListenAddrs() []string
+}

introspect/pb/Makefile

@@ -0,0 +1,11 @@
+PB = $(wildcard *.proto)
+GO = $(PB:.proto=.pb.go)
+
+all: $(GO)
+
+%.pb.go: %.proto
+	protoc --proto_path=$(PWD):$(PWD)/../..:$(GOPATH)/src --gogofaster_out=Mgoogle/protobuf/timestamp.proto=github.com/gogo/protobuf/types:. $<
+
+clean:
+	rm -f *.pb.go
+	rm -f *.go