Sort strings by key value - Golang

I have the following string blob in Go:

  AWS_FIREHOSE_US_WEST_2_ENDPOINT: https://foobar.firehose.us-west-2.amazonaws.com
  BOT_NAME: mybot
  DEV_MODE: false
  GITHUB_APP_ID: 1234
  GITHUB_INSTALLATION_ID: 1234
  GITHUB_ORG_NAME: myorg
  SERVICE_WHO_IS_WHO_DEFAULT_HOST: foo.bar
  SERVICE_WHO_IS_WHO_DEFAULT_PORT: 80
  SERVICE_WHO_IS_WHO_DEFAULT_PROTO: http
  TZ: UTC
  _APP_NAME: myapp
  _BUILD_ID: 12345
  _DEPLOYMENT_ID: dev--foo.d53
  _DEPLOY_ENV: dev
  _OTEL_COLLECTOR_URL: tcp://localhost:4317
  _POD_ACCOUNT: 12345
  _POD_ID: a6127c9c-2be8-4078-8c00-132d29fbecfc
  _POD_REGION: us-west-1
  _POD_SHORTNAME: us-west-1-dev-default
  _TEAM_OWNER: eng-infra
  _TRACING_ENABLED: false
  force_restart: 2024-01-02T19:00:59Z
  GITHUB_PRIVATE_KEY: -----BEGIN RSA PRIVATE KEY-----
  fofofofofofofofofofofofofofoofofofofofofofofofoffof
  barbabaabababababababababababababababababaababababa
  batbababtbabttbtbabtbtabtbtbtbtbtbabtbtbbtbtbtbttbt
  -----END RSA PRIVATE KEY-----

This is a single string in Golang, separated by "\n", so please notice, it's not sorted by the key: value pair. I need to sort it out by the primary key, what would be the best way to accomplish this?

I've tried the following method:

// sortLines sorts the lines in a blob of text.
func sortLines(blob string) string {
    var sorted sort.StringSlice
    sorted = strings.Split(blob, "\n")
    sorted.Sort()
    return strings.Join(sorted, "\n")
}

Please notice trying to sort by line won't work due to the fact the GITHUB_PRIVATE_KEY: contains multiple lines.

Solution

EDIT: Revised to handle all forms of ASCII Armor.

Your string is not a blob. It has a well-defined structure. It contains an ASCII Armor value:

GITHUB_PRIVATE_KEY: -----BEGIN RSA PRIVATE KEY-----
fofofofofofofofofofofofofofoofofofofofofofofofoffof
barbabaabababababababababababababababababaababababa
batbababtbabttbtbabtbtabtbtbtbtbtbabtbtbbtbtbtbttbt
-----END RSA PRIVATE KEY-----

IETF RFC 4880

6.2. Forming ASCII Armor

6.6. Example of an ASCII Armored Message

A case insensitive sort (insert ASCII Armor example into test data):

  AWS_FIREHOSE_US_WEST_2_ENDPOINT: https://foobar.firehose.us-west-2.amazonaws.com
  BOT_NAME: mybot
  DEV_MODE: false
  force_restart: 2024-01-02T19:00:59Z
  GITHUB_APP_ID: 1234
  GITHUB_INSTALLATION_ID: 1234
  GITHUB_ORG_NAME: myorg
  GITHUB_PRIVATE_KEY: -----BEGIN RSA PRIVATE KEY-----
  fofofofofofofofofofofofofofoofofofofofofofofofoffof
  barbabaabababababababababababababababababaababababa
  batbababtbabttbtbabtbtabtbtbtbtbtbabtbtbbtbtbtbttbt
  -----END RSA PRIVATE KEY-----
  IETF_RFC4880_ASCII_ARMOR_EXAMPLE: -----BEGIN PGP MESSAGE-----
  Version: OpenPrivacy 0.99

  yDgBO22WxBHv7O8X7O/jygAEzol56iUKiXmV+XmpCtmpqQUKiQrFqclFqUDBovzS
  vBSFjNSiVHsuAA==
  =njUN
  -----END PGP MESSAGE-----
  SERVICE_WHO_IS_WHO_DEFAULT_HOST: foo.bar
  SERVICE_WHO_IS_WHO_DEFAULT_PORT: 80
  SERVICE_WHO_IS_WHO_DEFAULT_PROTO: http
  TZ: UTC
  _APP_NAME: myapp
  _BUILD_ID: 12345
  _DEPLOYMENT_ID: dev--foo.d53
  _DEPLOY_ENV: dev
  _OTEL_COLLECTOR_URL: tcp://localhost:4317
  _POD_ACCOUNT: 12345
  _POD_ID: a6127c9c-2be8-4078-8c00-132d29fbecfc
  _POD_REGION: us-west-1
  _POD_SHORTNAME: us-west-1-dev-default
  _TEAM_OWNER: eng-infra
  _TRACING_ENABLED: false

https://go.dev/play/p/B3x_AbAvZHs

func sortConfig(config string) (string, error) {
    type KL struct {
        key, lines string
    }

    var kls []KL
    scnr := bufio.NewScanner(strings.NewReader(config))
    inArmor := false // ASCII Armor (IETF RFC4880)
    for scnr.Scan() {
        line := scnr.Text() + "\n"

        if inArmor {
            kls[len(kls)-1].lines += line
            armor := strings.TrimSpace(line)
            inArmor = !strings.HasPrefix(armor, "-----END ") ||
                !strings.HasSuffix(armor, "-----")
            continue
        }

        if len(strings.TrimSpace(line)) == 0 {
            continue
        }

        key, value, pair := strings.Cut(line, ":")
        if !pair {
            key, value = "", key
        }

        if pair {
            armor := strings.TrimSpace(value)
            inArmor = strings.HasPrefix(armor, "-----BEGIN ") &&
                strings.HasSuffix(armor, "-----")
        }

        key = strings.TrimSpace(key)
        key = strings.ToUpper(key) // case insensitive
        kls = append(kls, KL{key: key, lines: line})
    }
    if err := scnr.Err(); err != nil {
        return "", err
    }

    slices.SortStableFunc(kls, func(a, b KL) int {
        return cmp.Compare(a.key, b.key)
    })

    var b strings.Builder
    b.Grow(len(config))
    for _, kl := range kls {
        b.WriteString(kl.lines)
    }
    return b.String(), nil
}