add skylabify

cmd/skylabify/skylabify.go

@@ -0,0 +1,131 @@
+package main
+
+import (
+	"bufio"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+	"syscall"
+
+	"github.com/kschamplin/gotelem/skylab"
+	"github.com/urfave/cli/v2"
+)
+
+// this command can be used to decode candump logs and dump json output.
+
+func main() {
+
+	app := cli.NewApp()
+	app.Name = "skylabify"
+	app.Usage = "decode skylab packets"
+	app.ArgsUsage = "<input file>"
+	app.Commands = nil
+	app.Description = `skylabify can read in candump logs and output newline-delimited JSON.
+It is designed to make reading candumps fast and easy.
+
+skylabify can be combined with jq and candump to allow for advanced queries.
+
+Examples:
+	skylabify candump.txt
+
+	candump -L can0 | skylabify -
+
+	skylabify previous_candump.txt | jq <some json query>
+
+I highly suggest reading the manpages for candump and jq.  The -L option is
+required for piping candump into skylabify. Likewise, data should be stored with
+-l.
+
+`
+
+	app.Flags = []cli.Flag{
+		&cli.BoolFlag{
+			Name:    "verbose",
+			Aliases: []string{"v"},
+		},
+	}
+
+	app.Action = run
+	app.HideHelp = true
+	if err := app.Run(os.Args); err != nil {
+		panic(err)
+	}
+}
+
+func run(ctx *cli.Context) (err error) {
+	path := ctx.Args().Get(0)
+	if path == "" {
+		fmt.Printf("missing input file\n")
+		cli.ShowAppHelpAndExit(ctx, int(syscall.EINVAL))
+	}
+
+	var istream *os.File
+	if path == "-" {
+		istream = os.Stdin
+	} else {
+		istream, err = os.Open(path)
+		if err != nil {
+			return
+		}
+	}
+
+	canDumpReader := bufio.NewReader(istream)
+
+	for {
+		// dumpline looks like this:
+		// (1684538768.521889) can0 200#8D643546
+		dumpLine, err := canDumpReader.ReadString('\n')
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				return nil
+			}
+			return err
+		}
+		// remove trailing newline
+		dumpLine = strings.TrimSpace(dumpLine)
+
+		segments := strings.Split(dumpLine, " ")
+
+		var cd candumpJSON
+		// this is cursed but easiest way to get a float from a string.
+		fmt.Sscanf(segments[0], "(%g)", &cd.Timestamp)
+
+		// this is for the latter part, we need to split id/data
+		hexes := strings.Split(segments[2], "#")
+
+		// get the id
+		cd.Id, err = strconv.ParseUint(hexes[0], 16, 64)
+		if err != nil {
+			return err
+		}
+
+		// get the data to a []byte
+		rawData, err := hex.DecodeString(hexes[1])
+		if err != nil {
+			return err
+		}
+
+		// parse the data []byte to a skylab packet
+		cd.Data, err = skylab.FromCanFrame(uint32(cd.Id), rawData)
+		if err != nil {
+			return err
+		}
+
+		// format and print out.
+		out, _ := json.Marshal(cd)
+		fmt.Printf("%s\n", out)
+
+	}
+	return nil
+}
+
+type candumpJSON struct {
+	Timestamp float64       `json:"ts"`
+	Id        uint64        `json:"id"`
+	Data      skylab.Packet `json:"data"`
+}