chore: update readme with tcp support, fix lint warnings, update fati…

…h/color for example.

.golangci.yml

@@ -8,10 +8,19 @@ linters-settings:
 linters:
   enable-all: true
   disable:
+    # might be good to have for future refactoring
+    - wrapcheck 
+    - goerr113
+    - gocyclo
+    - cyclop
+    - exhaustive
+    - durationcheck
+    - errname
+
+    # generally disabled linters
+    - nolintlint
     - errcheck
     - gochecknoglobals
-    - gocyclo
-    - gocyclop
     - gocognit
     - lll
     - gomnd
@@ -24,8 +33,12 @@ linters:
     - varnamelen
     - nlreturn
     - exhaustruct
+    - nonamedreturns
+    - testpackage
+    - thelper
+    - ireturn
 
-    # offically deprecated
+    # officially deprecated
     - nosnakecase
     - maligned
     - exhaustivestruct
@@ -37,10 +50,17 @@ linters:
     - golint
 
 issues:
+  exclude-rules:
+    - path: "(.+)_test.go"
+      linters:
+        - maintidx
+        - unused
+
   exclude:
     - "G104: Errors unhandled." # turn off errcheck
-    - "declaration of \"[a-z]\" shadows declaration at .*_test.go" # ignore shadowing a single charcter varibles in tests
+    - "declaration of \"[a-z]\" shadows declaration at .*_test.go" # ignore shadowing a single character variables in tests
     - "receiver name [a-z]0 should be consistent with previous receiver name [a-z]" # when we want to operate on a copy
+    - "ST1016: methods on the same type should have the same receiver name .seen .. \"[a-z]0\", .. \"[a-z]\""
     - "error strings should not be capitalized or end with punctuation or a newline" # doesn't matter
     - "lines are duplicate of `crc.crc.go:" # ignore duplications in crc.go
     - "package should be `crc_test` instead of `crc`" # ignore white listed internal testing

README.md

@@ -220,25 +220,24 @@ Instead, a callback based API (like http server handler) is used for both server
 ## Implemented
 
 - Serial RTU
+- Modbus over TCP
 - Function Codes 1-6,15,16
 - Server and Client API
 - Server and Client Tester (examples/memory)
 
 ## Development
 
-This project is mostly stable, and I am using it in production.
+This project and API is stable, and I am using it in production.
 
-API stability is best effort. This means:
+My primary usage is RTU (over RS-485). TCP is also supported. Others may or may not be implemented in the future.
 
-- Changes should not break users code unless there is a compelling reason.
-
-- Code broken by API changes should not compile, new errors to user code should not be introduced silently. 
+Contribution to new or existing functionally, or just changing a private identifier public are welcome, as well as documentation, test, example code or any other improvements.
 
-- API changes will be documented to speed adoption of new versions.
+Development tools:
 
-My primary usage is RTU (over RS-485). Others may or may not be implemented in the future.
-
-Contribution to new or existing functionally, or just changing a private identifier public are welcome, as well as documentation, test, example code or any other improvements.
+- `go generate` runs `embedmd` to copy parts of the examples_test.go to this readme file
+- `golangci-lint run` for improvement hints. Ideally there are no warnings.
+- Use `go test -race -count=5 ./...` pre release.
 
 ## Breaking Changes
 
@@ -255,16 +254,18 @@ Contribution to new or existing functionally, or just changing a private identif
 
 Compatibility with a wide range of serial hardware/drivers. (good)
 
-Compatibility with existing Modbus environments. (good)
+Compatibility with existing Modbus environments, including non-compliance and extensions. (good)
 
 Recover from transmission errors and timeouts, to work continuously unattended. (good)
 
-Better test coverage that also tests error conditions. (todo) 
+Better test coverage that also tests error conditions. (todo)
 
-Fuzz testing. (todo) 
+Fuzz testing. (todo)
 
 ## Failover mode
 
+TLDR: do not use.
+
 Failover has landed in v0.2.0, but it should be considered less stable than the other parts.
 
 In mission-critical applications, or anywhere hardware redundancy is cheaper than downtime, having a standby system taking over in case of the failure of the primary system is desirable.

crc/crc.go

@@ -8,8 +8,8 @@ import (
 	"io"
 )
 
-// Table of CRC values for high–order byte
-var crcHighBytes = []byte{
+// Table of CRC values for high–order byte.
+var crcHighBytes = []byte{ //nolint:dupl
 	0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
 	0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
 	0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
@@ -28,8 +28,8 @@ var crcHighBytes = []byte{
 	0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
 }
 
-// Table of CRC values for low-order byte
-var crcLowBytes = []byte{
+// Table of CRC values for low-order byte.
+var crcLowBytes = []byte{ //nolint:dupl
 	0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04,
 	0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8,
 	0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC,
@@ -48,7 +48,7 @@ var crcLowBytes = []byte{
 	0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83, 0x41, 0x81, 0x80, 0x40,
 }
 
-// Cyclical Redundancy Checking
+// crc is Cyclical Redundancy Checking.
 type crc struct {
 	high byte
 	low  byte
@@ -87,7 +87,7 @@ func (c *crc) Sum16() uint16 {
 	return uint16(c.low)<<8 | uint16(c.high)
 }
 
-// Hash is a subset of hash.Hash
+// Hash is a subset of hash.Hash.
 type Hash interface {
 	// Write (via the embedded io.Writer interface) adds more data to the running hash.
 	// It never returns an error.

crc/rtu.go

@@ -1,6 +1,6 @@
 package crc
 
-// Validate return true if byte slice ends with valid crc
+// Validate return true if byte slice ends with valid CRC.
 func Validate(bs []byte) bool {
 	if len(bs) <= 2 {
 		return false

examples_test.go

@@ -1,6 +1,7 @@
 //go:generate embedmd -w README.md
 //go:generate sed -i -e 's/\t/\ \ \ \ /g' README.md
 
+//nolint:forbidigo
 package modbusone_test
 
 import (

failover_client_test.go

@@ -65,8 +65,8 @@ func TestFailoverClient(t *testing.T) {
 	// t.Skip()
 
 	id := byte(0x77)
-	clientA, clientB, pc, countA, countB, countC, close := connectMockClients(t, id)
-	defer close()
+	clientA, clientB, pc, countA, countB, countC, closeClients := connectMockClients(t, id)
+	defer closeClients()
 	exCount := &counter{Stats: &Stats{}}
 	resetCounts := func() {
 		exCount.reset()
@@ -106,7 +106,7 @@ func TestFailoverClient(t *testing.T) {
 		}
 		time.Sleep(serverProcessingTime)
 		if !pc.IsActive() {
-			t.Fatal("primaray client should be active")
+			t.Fatal("primary client should be active")
 		}
 	})
 

failover_rtu_client.go

@@ -18,7 +18,7 @@ type FailoverRTUClient struct {
 	actions              chan rtuAction
 }
 
-// FailoverRTUClient is also a Server
+// FailoverRTUClient is also a Server.
 var _ Server = &FailoverRTUClient{}
 
 // NewFailoverRTUClient create a new client with failover function communicating over SerialContext with the

failover_server_test.go

@@ -115,8 +115,8 @@ func connectToMockServers(t *testing.T, slaveID byte) (*RTUClient, *FailoverSeri
 
 func TestFailoverServer(t *testing.T) {
 	id := byte(0x77)
-	client, pc, countA, countB, countC, close := connectToMockServers(t, id)
-	defer close()
+	client, pc, countA, countB, countC, closeServers := connectToMockServers(t, id)
+	defer closeServers()
 	exCount := counter{Stats: &Stats{}}
 	resetCounts := func() {
 		exCount.reset()
@@ -155,7 +155,7 @@ func TestFailoverServer(t *testing.T) {
 		}
 		time.Sleep(serverProcessingTime * 2)
 		if !pc.IsActive() {
-			t.Fatal("primaray servers should be active")
+			t.Fatal("primary servers should be active")
 		}
 	})
 

go.mod

@@ -3,7 +3,7 @@ module github.com/xiegeo/modbusone
 go 1.14
 
 require (
-	github.com/fatih/color v1.9.0
+	github.com/fatih/color v1.13.0
 	github.com/tarm/serial v0.0.0-20180830185346-98f6abe2eb07
 	github.com/xiegeo/coloredgoroutine v0.1.1
 )

go.sum

@@ -1,18 +1,19 @@
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
-github.com/fatih/color v1.9.0 h1:8xPHl4/q1VyqGIPif1F+1V3Y3lSmrq01EabUW3CoW5s=
-github.com/fatih/color v1.9.0/go.mod h1:eQcE1qtQxscV5RaZvpXrrb8Drkc3/DdQ+uUYCNjL+zU=
+github.com/fatih/color v1.13.0 h1:8LOYc1KYPPmyKMuN8QV2DNRWNbLo6LZ0iLs8+mlH53w=
+github.com/fatih/color v1.13.0/go.mod h1:kLAiJbzzSOZDVNGyDpeOxJ47H46qBXwg5ILebYFFOfk=
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
-github.com/mattn/go-colorable v0.1.4 h1:snbPLB8fVfU9iwbbo30TPtbLRzwWu6aJS6Xh4eaaviA=
-github.com/mattn/go-colorable v0.1.4/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=
+github.com/mattn/go-colorable v0.1.9 h1:sqDoxXbdeALODt0DAeJCVp38ps9ZogZEAXjus69YV3U=
+github.com/mattn/go-colorable v0.1.9/go.mod h1:u6P/XSegPjTcexA+o6vUJrdnUu04hMope9wVRipJSqc=
 github.com/mattn/go-isatty v0.0.4/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
-github.com/mattn/go-isatty v0.0.8/go.mod h1:Iq45c/XA43vh69/j3iqttzPXn0bhXyGjM0Hdxcsrc5s=
-github.com/mattn/go-isatty v0.0.11 h1:FxPOTFNqGkuDUGi3H/qkUbQO4ZiBa2brKq5r0l8TGeM=
-github.com/mattn/go-isatty v0.0.11/go.mod h1:PhnuNfih5lzO57/f3n+odYbM4JtupLOxQOAqxQCu2WE=
+github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
+github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
+github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
 github.com/tarm/serial v0.0.0-20180830185346-98f6abe2eb07 h1:UyzmZLoiDWMRywV4DUYb9Fbt8uiOSooupjTq10vpvnU=
 github.com/tarm/serial v0.0.0-20180830185346-98f6abe2eb07/go.mod h1:kDXzergiv9cbyO7IOYJZWg1U88JhDg3PB6klq9Hg2pA=
 github.com/xiegeo/coloredgoroutine v0.1.1 h1:L6EaQHWIY+oIlKpj5ORu9hIorsLbQwTAStEHSp1SoAs=
 github.com/xiegeo/coloredgoroutine v0.1.1/go.mod h1:d3jyamWlthEBXOL5qUpKOaaKSJM75HuCIn/z9f4ylrs=
 golang.org/x/sys v0.0.0-20180831094639-fa5fdf94c789/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190222072716-a9d3bda3a223/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20191026070338-33540a1f6037 h1:YyJpGZS1sBuBCzLAR1VEpK193GlqGZbnPFnPV/5Rsb4=
-golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c h1:F1jZWGFhYfh0Ci55sIpILtKKK8p3i2/krTr0H1rg74I=
+golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

handler2serial_test.go

@@ -3,7 +3,6 @@ package modbusone_test
 import (
 	"bufio"
 	"bytes"
-	"fmt"
 	"io"
 	"os"
 	"sync"
@@ -125,7 +124,7 @@ func TestHandler(t *testing.T) {
 		sc.LastWritten = nil
 	}
 
-	t.Run(fmt.Sprintf("Read Coil Status (FC=01)"), func(t *testing.T) {
+	t.Run("Read Coil Status (FC=01)", func(t *testing.T) {
 		subtest = t
 		header, err := FcReadCoils.MakeRequestHeader(0x0013, 0x0025)
 		if err != nil {
@@ -154,7 +153,7 @@ func TestHandler(t *testing.T) {
 		testTrans(header, request, response)
 	})
 
-	t.Run(fmt.Sprintf("Read Input Status (FC=02)"), func(t *testing.T) {
+	t.Run("Read Input Status (FC=02)", func(t *testing.T) {
 		subtest = t
 		header, err := FcReadDiscreteInputs.MakeRequestHeader(0x00C4, 0x0016)
 		if err != nil {
@@ -181,7 +180,7 @@ func TestHandler(t *testing.T) {
 		testTrans(header, request, response)
 	})
 
-	t.Run(fmt.Sprintf("Read Holding Registers (FC=03)"), func(t *testing.T) {
+	t.Run("Read Holding Registers (FC=03)", func(t *testing.T) {
 		subtest = t
 		header, err := FcReadHoldingRegisters.MakeRequestHeader(0x006B, 0x0003)
 		if err != nil {
@@ -204,7 +203,7 @@ func TestHandler(t *testing.T) {
 		testTrans(header, request, response)
 	})
 
-	t.Run(fmt.Sprintf("Read Input Registers (FC=04)"), func(t *testing.T) {
+	t.Run("Read Input Registers (FC=04)", func(t *testing.T) {
 		subtest = t
 		header, err := FcReadInputRegisters.MakeRequestHeader(0x0008, 0x0001)
 		if err != nil {
@@ -227,7 +226,7 @@ func TestHandler(t *testing.T) {
 		testTrans(header, request, response)
 	})
 
-	t.Run(fmt.Sprintf("Write Single Coil (FC=05)"), func(t *testing.T) {
+	t.Run("Write Single Coil (FC=05)", func(t *testing.T) {
 		subtest = t
 		header, err := FcWriteSingleCoil.MakeRequestHeader(0x00AC, 1)
 		if err != nil {
@@ -250,7 +249,7 @@ func TestHandler(t *testing.T) {
 		testTrans(header, request, response)
 	})
 
-	t.Run(fmt.Sprintf("Write Single Register (FC=06)"), func(t *testing.T) {
+	t.Run("Write Single Register (FC=06)", func(t *testing.T) {
 		subtest = t
 		header, err := FcWriteSingleRegister.MakeRequestHeader(0x0001, 1)
 		if err != nil {
@@ -273,7 +272,7 @@ func TestHandler(t *testing.T) {
 		testTrans(header, request, response)
 	})
 
-	t.Run(fmt.Sprintf("Write Multiple Coils (FC=15)"), func(t *testing.T) {
+	t.Run("Write Multiple Coils (FC=15)", func(t *testing.T) {
 		subtest = t
 		header, err := FcWriteMultipleCoils.MakeRequestHeader(0x0013, 0x000A)
 		if err != nil {
@@ -298,7 +297,7 @@ func TestHandler(t *testing.T) {
 		}
 		testTrans(header, request, response)
 	})
-	t.Run(fmt.Sprintf("Write Multiple Registers (FC=16)"), func(t *testing.T) {
+	t.Run("Write Multiple Registers (FC=16)", func(t *testing.T) {
 		subtest = t
 		header, err := FcWriteMultipleRegisters.MakeRequestHeader(0x0001, 0x0002)
 		if err != nil {