Convert log File Data to Json Object in Vue client-CodePudding

I have a log file as follow:

{"L":"DEBUG","T":"2021-11-01T17:37:54.167 0530","M":"Route.go:74[IN : GetLatestLogs]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.167 0530","M":"Service.go:40[IN : GetRecentServerErrorLogService]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.167 0530","M":"DAO.go:117[IN : GetRecentServerErrorLogDAO]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.168 0530","M":"DAO.go:148[OUT : GetRecentServerErrorLogDAO]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.168 0530","M":"Service.go:47[OUT : GetRecentServerErrorLogService]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.168 0530","M":"Route.go:79[OUT : GetLatestLogs]"}
{"L":"DEBUG","T":"2021-11-01T17:40:55.331 0530","M":"Route.go:74[IN : GetLatestLogs]"}

I am reading this file in the Golang echo server as follow:

file, err := os.Open(logFilePath)

stat, _ := os.Stat(logFilePath)
buf := make([]byte, stat.Size())
_, err = file.Read(buf)
serverLog := string(buf)

and return this string generated back

return c.JSON(http.StatusOK, serverLog)

this is what I get as result

"{\"L\":\"DEBUG\",\"T\":\"2021-11-01T17:37:54.167 0530\",\"M\":\"Route.go:74[IN : GetLatestLogs]\"}\n{\"L\":\"DEBUG\",\"T\":\"2021-11-01T17:37:54.167 0530\",\"M\":\"Service.go:40[IN : GetRecentServerErrorLogService]\"}\n{\"L\":\"DEBUG\",\"T\":\"2021-11-01T17:37:54.167 0530\",\"M\":\"DAO.go:117[IN : GetRecentServerErrorLogDAO]\"}\n{\"L\":\"DEBUG\",\"T\":\"2021-11-01T17:37:54.168 0530\",\"M\":\"DAO.go:148[OUT : GetRecentServerErrorLogDAO]\"}\n{\"L\":\"DEBUG\",\"T\":\"2021-11-01T17:37:54.168 0530\",\"M\":\"Service.go:47[OUT : GetRecentServerErrorLogService]\"}\n{\"L\":\"DEBUG\",\"T\":\"2021-11-01T17:37:54.168 0530\",\"M\":\"Route.go:79[OUT : GetLatestLogs]\"}\n{\"L\":\"DEBUG\",\"T\":\"2021-11-01T17:40:55.331 0530\",\"M\":\"Route.go:74[IN : GetLatestLogs]\"}{\"L\":\"DEBUG\",\"T\":\"2021-11-02T09:48:49.982 0530\",\"M\":\"controlPanelRoute.go:74[IN : GetLatestLogs]\"}\n{\"L\":\"DEBUG\",\"T\":\"2021-11-02T09:48:49.982 0530\",\"M\":\"controlPanelService.go:40[IN : GetRecentServerErrorLogService]\"}\n{\"L\":\"DEBUG\",\"T\":\"2021-11-02T09:48:49.982 0530\",\"M\":\"controlPanelDAO.go:117[IN : GetRecentServerErrorLogDAO]\"}\n"

I want to convert this received response to a JSON object.

This is my desired output:

[
    {
        "L": "DEBUG",
        "T": "2021-11-01T17:37:54.167 0530",
        "M": "Route.go:74[IN : GetLatestLogs]"
    },
    {
        "L": "DEBUG",
        "T": "2021-11-01T17:37:54.167 0530",
        "M": "Service.go:40[IN : GetRecentServerErrorLogService]"
    },
    {
        "L": "DEBUG",
        "T": "2021-11-01T17:37:54.167 0530",
        "M": "DAO.go:117[IN : GetRecentServerErrorLogDAO]"
    },
    {
        "L": "DEBUG",
        "T": "2021-11-01T17:37:54.168 0530",
        "M": "DAO.go:148[OUT : GetRecentServerErrorLogDAO]"
    },
    {
        "L": "DEBUG",
        "T": "2021-11-01T17:37:54.168 0530",
        "M": "Service.go:47[OUT : GetRecentServerErrorLogService]"
    },
    {
        "L": "DEBUG",
        "T": "2021-11-01T17:37:54.168 0530",
        "M": "Route.go:79[OUT : GetLatestLogs]"
    },
    {
        "L": "DEBUG",
        "T": "2021-11-01T17:40:55.331 0530",
        "M": "Route.go:74[IN : GetLatestLogs]"
    }
]

CodePudding user response：

That looks like one valid Json statement after another. You can open the file, create a decoder with json.NewDecoder(filehandle), and read one Json statement out if it after another. Heres' an example with the input hard coded:

package main

import (
    "fmt"
    "bytes"
    "io"
    "encoding/json"
)

var input =[]byte( `{"L":"DEBUG","T":"2021-11-01T17:37:54.167 0530","M":"Route.go:74[IN : GetLatestLogs]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.167 0530","M":"Service.go:40[IN : GetRecentServerErrorLogService]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.167 0530","M":"DAO.go:117[IN : GetRecentServerErrorLogDAO]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.168 0530","M":"DAO.go:148[OUT : GetRecentServerErrorLogDAO]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.168 0530","M":"Service.go:47[OUT : GetRecentServerErrorLogService]"}
{"L":"DEBUG","T":"2021-11-01T17:37:54.168 0530","M":"Route.go:79[OUT : GetLatestLogs]"}
{"L":"DEBUG","T":"2021-11-01T17:40:55.331 0530","M":"Route.go:74[IN : GetLatestLogs]"}`)

func main() {
    r := json.NewDecoder(bytes.NewBuffer(input))
    var data interface{}
    for i := 0;;i  {
        if err := r.Decode(&data); err != nil {
            if err == io.EOF {
                break
            }
            panic(err)
        } else {
            fmt.Printf("%d: % v\n", i, data)
        }
    }
}

Output should be:

0: map[L:DEBUG M:Route.go:74[IN : GetLatestLogs] T:2021-11-01T17:37:54.167 0530]
1: map[L:DEBUG M:Service.go:40[IN : GetRecentServerErrorLogService] T:2021-11-01T17:37:54.167 0530]
2: map[L:DEBUG M:DAO.go:117[IN : GetRecentServerErrorLogDAO] T:2021-11-01T17:37:54.167 0530]
3: map[L:DEBUG M:DAO.go:148[OUT : GetRecentServerErrorLogDAO] T:2021-11-01T17:37:54.168 0530]
4: map[L:DEBUG M:Service.go:47[OUT : GetRecentServerErrorLogService] T:2021-11-01T17:37:54.168 0530]
5: map[L:DEBUG M:Route.go:79[OUT : GetLatestLogs] T:2021-11-01T17:37:54.168 0530]
6: map[L:DEBUG M:Route.go:74[IN : GetLatestLogs] T:2021-11-01T17:40:55.331 0530]

As you can see, Decode() stops at the end of a Json expression, so you can just keep reading over and over again.

CodePudding user response：

file, err := os.Open("/log/file/path")
if err != nil {
    panic(err)
}
info, err := file.Stat()
if err != nil {
    panic(err)
}

logs := make(json.RawMessage, 1, info.Size() 1) // len=1 for '['
dec := json.NewDecoder(file)
for dec.More() {
    var log json.RawMessage
    if err := dec.Decode(&log); err != nil {
        panic(err)
    }

    logs = append(logs, log...)
    logs = append(logs, ',')
}
if n := len(logs); n > 1 {
    logs[0], logs[n-1] = '[', ']'
    c.JSON(http.StatusOK, logs)
}