17 files changed, 84 insertions, 22 deletions
diff --git a/.gitignore b/.gitignore
index 0f9e2cb..f0ab2aa 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,3 @@
 .idea
-binapi_generator/binapi_generator
+cmd/binapi-generator/binapi-generator
 examples/examples
diff --git a/Makefile b/Makefile
index a11ffa4..70f1f45 100644
--- a/Makefile
+++ b/Makefile
@@ -1,16 +1,18 @@
 build:
-	@cd binapi_generator && go build -v
+	@cd cmd/binapi-generator && go build -v
+	@cd examples && go build -v
 
 test:
-	@cd binapi_generator && go test -cover .
+	@cd cmd/binapi-generator && go test -cover .
 	@cd api && go test -cover ./...
 	@cd core && go test -cover .
 
 install:
-	@cd binapi_generator && go install -v
+	@cd cmd/binapi-generator && go install -v
 
 clean:
-	@rm binapi_generator/binapi_generator
+	@rm cmd/binapi-generator/binapi-generator
+	@rm examples/examples
 
 generate:
 	@cd core && go generate ./...
diff --git a/README.md b/README.md
index 1d52083..a7d80d9 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ This set of packages provide the API for communication with VPP from Go. It cons
 - [api](api/api.go): API for communication with govpp core using Go channels (without the need of importing the govpp core package itself),
 - [core](core/): main functionality of the govpp, sends and receives the messages to/from VPP using the adapter, marshalls/unmarshalls them and forwards them between the client Go channels and the VPP,
 - [adapter](adapter/): adapter between govpp core and the VPP, responsible for sending and receiving binary-encoded data via shared memory,
-- [binapi_generator](binapi_generator/generator.go): Generator of Go structs out of the VPP binary API definitions in JSON format,
+- [binapi-generator](cmd/binapi-generator/generator.go): Generator of Go structs out of the VPP binary API definitions in JSON format,
 - [examples](examples/): example VPP management application that exercises the govpp API on real-world use-cases.
 
 The design with separated govpp API package ([api](api/api.go)) and the govpp core package ([core](core/)) enables 
@@ -44,7 +44,7 @@ binary API |                    +------+  govpp API   |
 Generating Go bindings from the JSON files located in the `/usr/share/vpp/api/` directory 
 into the Go packages that will be created inside of the `bin_api` directory:
 ```
-go run binapi_generator/generator.go --input-dir=/usr/share/vpp/api/ --output-dir=bin_api
+binapi-generator --input-dir=/usr/share/vpp/api/ --output-dir=bin_api
 ```
 
 Usage of the generated bindings:
@@ -114,22 +114,22 @@ make install
 
 
 ## Building Go bindings from VPP binary APIs
-Once you have `binapi_generator` installed in your `$GOPATH`, you can use it to generate Go bindings from
+Once you have `binapi-generator` installed in your `$GOPATH`, you can use it to generate Go bindings from
 VPP APis in JSON format. The JSON input can be specified as a single file (`input-file` argument), or
 as a directory that will be scanned for all `.json` files (`input-dir`). The generated Go bindings will
 be placed into `output-dir` (by default current working directory), where each Go package will be placed into 
 a separated directory, e.g.:
 
 ```
-binapi_generator --input-file=examples/bin_api/acl.api.json --output-dir=examples/bin_api
-binapi_generator --input-dir=examples/bin_api --output-dir=examples/bin_api
+binapi-generator --input-file=examples/bin_api/acl.api.json --output-dir=examples/bin_api
+binapi-generator --input-dir=examples/bin_api --output-dir=examples/bin_api
 ```
 
 In Go, [go generate](https://blog.golang.org/generate) tool can be leveraged to ease the code generation
 process. It allows to specify generator instructions in any one of the regular (non-generated) `.go` files
 that are dependent on generated code using special comments, e.g. the one from [example_client](examples/example_client.go):
 ```go
-// go:generate binapi_generator --input-dir=bin_api --output-dir=bin_api
+// go:generate binapi-generator --input-dir=bin_api --output-dir=bin_api
 ```
 
 The comment must start at the beginning of the line and have no spaces between the `//` and the `go:generate`. 
diff --git a/api/api.go b/api/api.go
index f478bf1..fe6a34a 100644
--- a/api/api.go
+++ b/api/api.go
@@ -32,7 +32,7 @@ const (
 	OtherMessage
 )
 
-// Message is an interface that is implemented by all VPP Binary API messages generated by the binapi_generator.
+// Message is an interface that is implemented by all VPP Binary API messages generated by the binapi-generator.
 type Message interface {
 	// GetMessageName returns the original VPP name of the message, as defined in the VPP API.
 	GetMessageName() string
@@ -44,7 +44,7 @@ type Message interface {
 	GetCrcString() string
 }
 
-// DataType is an interface that is implemented by all VPP Binary API data types by the binapi_generator.
+// DataType is an interface that is implemented by all VPP Binary API data types by the binapi-generator.
 type DataType interface {
 	// GetTypeName returns the original VPP name of the data type, as defined in the VPP API.
 	GetTypeName() string
diff --git a/api/ifcounters/doc.go b/api/ifcounters/doc.go
index c918941..35c7f7b 100644
--- a/api/ifcounters/doc.go
+++ b/api/ifcounters/doc.go
@@ -1,4 +1,29 @@
 // Package ifcounters provides the helper API for decoding VnetInterfaceCounters binary API message
 // that contains binary-encoded statistics data into the Go structs that are better consumable by the Go code.
-// TODO: example usage - currently in the example_client.go
+//
+// VPP provides two types of interface counters that can be encoded inside of a single VnetInterfaceCounters
+// message: simple and combined. For both of them, ifcounters API provides a separate decode function:
+// DecodeCounters or DecodeCombinedCounters. The functions return a slice of simple or combined counters respectively:
+//
+//	notifMsg := <-notifChan:
+//	notif := notifMsg.(*interfaces.VnetInterfaceCounters)
+//
+//	if notif.IsCombined == 0 {
+//		// simple counter
+//		counters, err := ifcounters.DecodeCounters(ifcounters.VnetInterfaceCounters(*notif))
+//		if err != nil {
+//			fmt.Println("Error:", err)
+//		} else {
+//			fmt.Printf("%+v\n", counters)
+//		}
+//	} else {
+//		// combined counter
+//		counters, err := ifcounters.DecodeCombinedCounters(ifcounters.VnetInterfaceCounters(*notif))
+//		if err != nil {
+//			fmt.Println("Error:", err)
+//		} else {
+//			fmt.Printf("%+v\n", counters)
+//		}
+//	}
+//
 package ifcounters
diff --git a/binapi_generator/doc.go b/cmd/binapi-generator/doc.go
index 84a971b..e8556ec 100644
--- a/binapi_generator/doc.go
+++ b/cmd/binapi-generator/doc.go
@@ -7,7 +7,7 @@
 // where each Go package will be placed into its own separate directory,
 // for example:
 //
-//    binapi_generator --input-file=examples/bin_api/acl.api.json --output-dir=examples/bin_api
-//    binapi_generator --input-dir=examples/bin_api --output-dir=examples/bin_api
+//    binapi-generator --input-file=examples/bin_api/acl.api.json --output-dir=examples/bin_api
+//    binapi-generator --input-dir=examples/bin_api --output-dir=examples/bin_api
 //
 package main
diff --git a/binapi_generator/generator.go b/cmd/binapi-generator/generator.go
index 22fe3e1..22fe3e1 100644
--- a/binapi_generator/generator.go
+++ b/cmd/binapi-generator/generator.go
diff --git a/binapi_generator/generator_test.go b/cmd/binapi-generator/generator_test.go
index 7527a98..7527a98 100644
--- a/binapi_generator/generator_test.go
+++ b/cmd/binapi-generator/generator_test.go
diff --git a/binapi_generator/testdata/acl.api.json b/cmd/binapi-generator/testdata/acl.api.json
index 91d3d2f..91d3d2f 100644
--- a/binapi_generator/testdata/acl.api.json
+++ b/cmd/binapi-generator/testdata/acl.api.json
diff --git a/binapi_generator/testdata/af_packet.api.json b/cmd/binapi-generator/testdata/af_packet.api.json
index 211fc3e..211fc3e 100644
--- a/binapi_generator/testdata/af_packet.api.json
+++ b/cmd/binapi-generator/testdata/af_packet.api.json
diff --git a/binapi_generator/testdata/input-generate-error.json b/cmd/binapi-generator/testdata/input-generate-error.json
index d5df76e..d5df76e 100644
--- a/binapi_generator/testdata/input-generate-error.json
+++ b/cmd/binapi-generator/testdata/input-generate-error.json
diff --git a/binapi_generator/testdata/input-read-json-error.json b/cmd/binapi-generator/testdata/input-read-json-error.json
index 02691e3..02691e3 100644
--- a/binapi_generator/testdata/input-read-json-error.json
+++ b/cmd/binapi-generator/testdata/input-read-json-error.json
diff --git a/binapi_generator/testdata/input.txt b/cmd/binapi-generator/testdata/input.txt
index e69de29..e69de29 100644
--- a/binapi_generator/testdata/input.txt
+++ b/cmd/binapi-generator/testdata/input.txt
diff --git a/binapi_generator/testdata/ip.api.json b/cmd/binapi-generator/testdata/ip.api.json
index 970ec4b..970ec4b 100644
--- a/binapi_generator/testdata/ip.api.json
+++ b/cmd/binapi-generator/testdata/ip.api.json
diff --git a/core/core.go b/core/core.go
index 550b6a7..5b14a42 100644
--- a/core/core.go
+++ b/core/core.go
@@ -14,7 +14,7 @@
 
 package core
 
-//go:generate binapi_generator --input-file=/usr/share/vpp/api/vpe.api.json --output-dir=./bin_api
+//go:generate binapi-generator --input-file=/usr/share/vpp/api/vpe.api.json --output-dir=./bin_api
 
 import (
 	"errors"
@@ -40,7 +40,7 @@ type Connection struct {
 	vpp   adapter.VppAdapter // VPP adapter
 	codec *MsgCodec          // message codec
 
-	msgIDs     map[string]uint16 // map os message IDs indexed by message name + CRC
+	msgIDs     map[string]uint16 // map of message IDs indexed by message name + CRC
 	msgIDsLock sync.RWMutex      // lock for the message IDs map
 
 	channels     map[uint32]*api.Channel // map of all API channels indexed by the channel ID
@@ -112,6 +112,9 @@ func Connect(vppAdapter adapter.VppAdapter) (*Connection, error) {
 
 // Disconnect disconnects from VPP.
 func (c *Connection) Disconnect() {
+	if c == nil {
+		return
+	}
 	connLock.Lock()
 	defer connLock.Unlock()
 
@@ -124,12 +127,18 @@ func (c *Connection) Disconnect() {
 // NewAPIChannel returns a new API channel for communication with VPP via govpp core.
 // It uses default buffer sizes for the request and reply Go channels.
 func (c *Connection) NewAPIChannel() (*api.Channel, error) {
+	if c == nil {
+		return nil, errors.New("nil connection passed in")
+	}
 	return c.NewAPIChannelBuffered(requestChannelBufSize, replyChannelBufSize)
 }
 
 // NewAPIChannelBuffered returns a new API channel for communication with VPP via govpp core.
 // It allows to specify custom buffer sizes for the request and reply Go channels.
 func (c *Connection) NewAPIChannelBuffered(reqChanBufSize, replyChanBufSize int) (*api.Channel, error) {
+	if c == nil {
+		return nil, errors.New("nil connection passed in")
+	}
 	chID := atomic.AddUint32(&c.maxChannelID, 1)
 	chMeta := &channelMetadata{id: chID}
 
@@ -311,6 +320,9 @@ func sendReply(ch *api.Channel, reply *api.VppReply) {
 
 // GetMessageID returns message identifier of given API message.
 func (c *Connection) GetMessageID(msg api.Message) (uint16, error) {
+	if c == nil {
+		return 0, errors.New("nil connection passed in")
+	}
 	return c.messageNameToID(msg.GetMessageName(), msg.GetCrcString())
 }
 
diff --git a/core/core_test.go b/core/core_test.go
index 8bf9311..d3c2e2c 100644
--- a/core/core_test.go
+++ b/core/core_test.go
@@ -144,6 +144,20 @@ func TestNotifications(t *testing.T) {
 	Expect(err).ShouldNot(HaveOccurred())
 }
 
+func TestNilConnection(t *testing.T) {
+	var conn *Connection
+
+	ch, err := conn.NewAPIChannel()
+	Expect(ch).Should(BeNil())
+	Expect(err).Should(HaveOccurred())
+	Expect(err.Error()).To(ContainSubstring("nil"))
+
+	ch, err = conn.NewAPIChannelBuffered(1, 1)
+	Expect(ch).Should(BeNil())
+	Expect(err).Should(HaveOccurred())
+	Expect(err.Error()).To(ContainSubstring("nil"))
+}
+
 func TestDoubleConnection(t *testing.T) {
 	ctx := setupTest(t)
 	defer ctx.teardownTest()
diff --git a/examples/example_client.go b/examples/example_client.go
index 6030469..f2e5804 100644
--- a/examples/example_client.go
+++ b/examples/example_client.go
@@ -16,7 +16,7 @@
 package main
 
 // Generates Go bindings for all VPP APIs located in the json directory.
-//go:generate binapi_generator --input-dir=bin_api --output-dir=bin_api
+//go:generate binapi-generator --input-dir=bin_api --output-dir=bin_api
 
 import (
 	"fmt"
@@ -36,11 +36,20 @@ import (
 func main() {
 	fmt.Println("Starting example VPP client...")
 
-	// connect to VPP and create an API channel that will be used in the examples
-	conn, _ := govpp.Connect()
+	// connect to VPP
+	conn, err := govpp.Connect()
+	if err != nil {
+		fmt.Println("Error:", err)
+		os.Exit(1)
+	}
 	defer conn.Disconnect()
 
-	ch, _ := conn.NewAPIChannel()
+	// create an API channel that will be used in the examples
+	ch, err := conn.NewAPIChannel()
+	if err != nil {
+		fmt.Println("Error:", err)
+		os.Exit(1)
+	}
 	defer ch.Close()
 
 	// check whether the VPP supports our version of some messages