feat(attributes): add default attributes (#24)

Add fields:
    

application.session: an uuid that will be the same for all reports in
single application session.
    
    guid: unique machine identifier 

    uname.sysname - name of the operating system

backtrace.agent - name of the go library (this is a constant value set
to backtrace-go)

    backtrace.version - version of the go library 

    uname.version - version of the operating system

    hostname - current hostname

    cpu.arch - CPU arch

    cpu.brand - CPU brand

    application - current application name 

    process.id  - current process id

go.mod

@@ -3,6 +3,7 @@ module github.com/backtrace-labs/backtrace-go
 go 1.22
 
 require (
+	github.com/google/uuid v1.6.0
 	github.com/stretchr/testify v1.9.0
 	golang.org/x/sys v0.25.0
 )

go.sum

@@ -1,5 +1,7 @@
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=

main.go

@@ -6,20 +6,43 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log"
 	mathrand "math/rand"
 	"net/http"
 	"net/url"
 	"os"
+	"os/exec"
+	"path/filepath"
 	"runtime"
 	"strings"
 	"time"
+
+	"github.com/google/uuid"
+)
+
+const (
+	VersionMajor = 1
+	VersionMinor = 0
+	VersionPatch = 0
 )
 
-const VersionMajor = 0
-const VersionMinor = 0
-const VersionPatch = 0
+var (
+	Version = fmt.Sprintf("%d.%d.%d", VersionMajor, VersionMinor, VersionPatch)
+
+	windowsGUIDCommand = []string{"reg", "query", "\"HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Cryptography\"", "/v", "MachineGuid"}
+	linuxGUIDCommand   = []string{"sh", "-c", "( cat /var/lib/dbus/machine-id /etc/machine-id 2> /dev/null || hostname ) | head -n 1 || :"}
+	freebsdGUIDCommand = []string{"sh", "-c", "kenv -q smbios.system.uuid || sysctl -n kern.hostuuid"}
+	darwinGUIDCommand  = []string{"sh", "-c", "ioreg -rd1 -c IOPlatformExpertDevice | grep IOPlatformUUID | awk -F'= \"' '{print $2}' | tr -d '\"'"}
 
-var Version = fmt.Sprintf("%d.%d.%d", VersionMajor, VersionMinor, VersionPatch)
+	windowsCPUCommand = []string{"wmic", "CPU", "get", "NAME"}
+	linuxCPUCommand   = []string{"sh", "-c", "lscpu | grep \"Model name\" | awk -F':' '{print $2}' | sed 's/^[[:space:]]*//'"}
+	darwinCPUCommand  = []string{"sh", "-c", "sysctl -n machdep.cpu.brand_string"}
+	freebsdCPUCommand = []string{"sh", "-c", "sysctl -n hw.model"}
+
+	linuxOSVersionCommand   = []string{"sh", "-c", "cat /etc/os-release | grep VERSION= | awk -F'=\"' '{print $2}' | tr -d '\"'"}
+	darwinOSVersionCommand  = []string{"sh", "-c", "sw_vers | grep ProductVersion | awk -F':' '{print $2}' | tr -d '\t'"}
+	freebsdOSVersionCommand = []string{"sh", "-c", "cat /etc/os-release | grep VERSION= | awk -F'=\"' '{print $2}' | tr -d '\"'"}
+)
 
 type OptionsStruct struct {
 	Endpoint string
@@ -72,9 +95,97 @@ func init() {
 	randSource := mathrand.NewSource(seed)
 	rng = mathrand.New(randSource)
 
+	setDefaultAttributes()
+
 	go sendWorkerMain()
 }
 
+func setDefaultAttributes() {
+	if Options.Attributes == nil {
+		Options.Attributes = make(map[string]interface{})
+	}
+
+	hostName, _ := os.Hostname()
+	Options.Attributes["backtrace.version"] = Version
+	Options.Attributes["backtrace.agent"] = "backtrace-go"
+	Options.Attributes["hostname"] = hostName
+	Options.Attributes["uname.sysname"] = runtime.GOOS
+	Options.Attributes["cpu.arch"] = runtime.GOARCH
+	Options.Attributes["process.id"] = os.Getpid()
+	Options.Attributes["application.session"] = uuid.New()
+	Options.Attributes["application"] = filepath.Base(os.Args[0])
+
+	guiCommand := []string{}
+	cpuCommand := []string{}
+	osCommand := []string{}
+	switch runtime.GOOS {
+	case "windows":
+		guiCommand = windowsGUIDCommand
+		cpuCommand = windowsCPUCommand
+	case "linux":
+		guiCommand = linuxGUIDCommand
+		cpuCommand = linuxCPUCommand
+		osCommand = linuxOSVersionCommand
+	case "darwin":
+		guiCommand = darwinGUIDCommand
+		cpuCommand = darwinCPUCommand
+		osCommand = darwinOSVersionCommand
+	case "freebsd":
+		guiCommand = freebsdGUIDCommand
+		cpuCommand = freebsdCPUCommand
+		osCommand = freebsdOSVersionCommand
+	}
+
+	if len(guiCommand) > 0 {
+		if output := execCommand(guiCommand); output != "" {
+			if runtime.GOOS == "windows" {
+				// windows gives:
+				// HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography
+				//    MachineGuid    REG_SZ    {XXXX-XXXX-XXXX-XXXX-XXXX}
+				if splitOutput := strings.Split(output, "{"); len(splitOutput) > 1 {
+					output = strings.TrimSuffix(splitOutput[1], "}")
+				}
+			}
+
+			Options.Attributes["guid"] = output
+		}
+	}
+
+	if len(cpuCommand) > 0 {
+		if output := execCommand(cpuCommand); output != "" {
+			if runtime.GOOS == "windows" {
+				// windows gives:
+				//NAME
+				//Intel(R) Core(TM) i7-9700K CPU @ 3.60GHz
+				if splitOutput := strings.Split(output, "\n"); len(splitOutput) > 1 {
+					output = splitOutput[1]
+				}
+			}
+
+			Options.Attributes["cpu.brand"] = output
+		}
+	}
+
+	if len(osCommand) > 0 {
+		if output := execCommand(osCommand); output != "" {
+			Options.Attributes["uname.version"] = output
+		}
+	}
+}
+
+// first value in array is command to exec, rest are arguments.
+// e.g. []string{"sh", "-c", "sysctl -n foo_bar | grep foo_bar | tr -d "foo_var" "}
+func execCommand(commands []string) string {
+	out, err := exec.Command(commands[0], commands[1:]...).Output()
+	if err != nil {
+		if Options.DebugBacktrace {
+			log.Println(err)
+		}
+	}
+
+	return string(out)
+}
+
 func Report(object interface{}, extraAttributes map[string]interface{}) {
 	if extraAttributes == nil {
 		extraAttributes = map[string]interface{}{}

main_test.go

@@ -103,4 +103,11 @@ func causeErrorReport() {
 	go doSomething(make(chan int))
 	Report(errors.New("it broke"), nil)
 	finishSendingReports(false)
+
+	for _, v := range []string{"backtrace.version", "backtrace.agent", "hostname", "uname.sysname", "cpu.arch", "process.id", "application.session", "application"} {
+		if _, ok := Options.Attributes[v]; !ok {
+			panic(v + " - attribute not set")
+		}
+	}
+
 }