Merge branch 'feat/envsubst-enhancements' into 'master'

3. any [custom variable](https://docs.gitlab.com/ee/ci/variables/#for-a-project)

    (ex: `${SECRET_TOKEN}` that you have set in your project CI/CD variables)

While your scripts may simply use any of those variables, your [values](https://helm.sh/docs/chart_best_practices/values/) files can use  **variable substitution**

with the syntax `${VARIABLE_NAME}`.

Each of those patterns will be dynamically replaced in your files by the template right before using it.

#### Variables substitution mechanism (in values files)

> :warning: 

>

> In order to be properly replaced, variables in your YAML value files shall be written with curly braces (ex: `${MYVAR}` and not `$MYVAR`).

> Multiline variables must be surrounded by double quotes and you might have to disable line-length rule of yamllint as they are rewritten on a single line.

> 

> ```yaml

>  tlsKey: "${MYKEY}"  # yamllint disable-line rule:line-length

> ```

While your scripts may freely use any of the available variables, your [values files](https://helm.sh/docs/chart_best_practices/values/) 

can use a **variable substitution** mechanism implemented by the template:

- Using the syntax `${VARIABLE_NAME}` or `%{VARIABLE_NAME}`.

  :warning: Curly braces (`{}`) are mandatory in the expression (`$VARIABLE_NAME` won't be processed).

- Each of those expressions will be **dynamically expanded** in your resource files with the variable value, right before being used.

- Variable substitution expressions **must be contained in double-quoted strings**.

  The substitution implementation takes care of escaping characters that need to be (double quote `"`, backslash `\`, tab `\t`, carriage return `\n` and line feed `\r`).

- Variable substitution can be prevented by appending `# nosubst` at the end of any line.

### Environments URL management

    fi

  }

  function awkenvsubst() {

    # performs variables escaping: '&' for gsub + JSON chars ('\' and '"')

    awk '{while(match($0,"[$%]{[^}]*}")) {var=substr($0,RSTART+2,RLENGTH-3);val=ENVIRON[var];gsub(/["\\&]/,"\\\\&",val);gsub("[$%]{"var"}",val)}}1'

  function tbc_envsubst() {

    awk '

      BEGIN {

        count_replaced_lines = 0

        # ASCII codes

        for (i=0; i<=255; i++)

          char2code[sprintf("%c", i)] = i

      }

      # determine encoding (from env or from file extension)

      function encoding() {

        enc = ENVIRON["TBC_ENVSUBST_ENCODING"]

        if (enc != "")

          return enc

        if (match(FILENAME, /\.(json|yaml|yml)$/))

          return "jsonstr"

        return "raw"

      }

      # see: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent

      function uriencode(str) {

        len = length(str)

        enc = ""

        for (i=1; i<=len; i++) {

          c = substr(str, i, 1);

          if (index("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.!~*'\''()", c))

            enc = enc c

          else

            enc = enc "%" sprintf("%02X", char2code[c])

        }

        return enc

      }

      !/# *nosubst/ {

        orig_line = $0

        line = $0

        count_repl_in_line = 0

        # /!\ 3rd arg (match) not supported in BusyBox awk

        while (match(line, /[$%]\{([[:alnum:]_]+)\}/)) {

          expr_start = RSTART

          expr_len = RLENGTH

          # get var name

          var = substr(line, expr_start+2, expr_len-3)

          # get var value (from env)

          val = ENVIRON[var]

          # check variable is set

          if (val == "") {

            printf("[\033[1;93mWARN\033[0m] Environment variable \033[33;1m%s\033[0m is not set or empty\n", var) > "/dev/stderr"

          } else {

            enc = encoding()

            if (enc == "jsonstr") {

              gsub(/["\\]/, "\\\\&", val)

              gsub("\n", "\\n", val)

              gsub("\r", "\\r", val)

              gsub("\t", "\\t", val)

            } else if (enc == "uricomp") {

              val = uriencode(val)

            } else if (enc == "raw") {

            } else {

              printf("[\033[1;93mWARN\033[0m] Unsupported encoding \033[33;1m%s\033[0m: ignored\n", enc) > "/dev/stderr"

            }

          }

          # replace expression in line

          line = substr(line, 1, expr_start - 1) val substr(line, expr_start + expr_len)

          count_repl_in_line++

        }

        if (count_repl_in_line) {

          if (count_replaced_lines == 0)

            printf("[\033[1;94mINFO\033[0m] Variable expansion occurred in file \033[33;1m%s\033[0m:\n", FILENAME) > "/dev/stderr"

          count_replaced_lines++

          printf("> line %s: %s\n", NR, orig_line) > "/dev/stderr"

        }

        print line

      }

    ' "$@"

  }

  function exec_hook() {

    environment_url=${ENV_URL:-$HELM_ENVIRONMENT_URL}

    # variables expansion in $environment_url

    environment_url=$(echo "$environment_url" | awkenvsubst)

    environment_url=$(echo "$environment_url" | TBC_ENVSUBST_ENCODING=uricomp tbc_envsubst)

    export environment_url

    # extract hostname from $environment_url

    hostname=$(echo "$environment_url" | awk -F[/:] '{print $4}')

    if [ -n "$HELM_COMMON_VALUES" ]; then

      log_info "--- using \\e[32mcommon values\\e[0m file: \\e[33;1m${HELM_COMMON_VALUES}\\e[0m"

      awkenvsubst < "$HELM_COMMON_VALUES" > generated-values-common.yml

      TBC_ENVSUBST_ENCODING=jsonstr tbc_envsubst "$HELM_COMMON_VALUES" > generated-values-common.yml

      helm_opts="$helm_opts --values generated-values-common.yml"

    fi

    if [ -n "$values_files" ]; then

      log_info "--- using \\e[32mvalues\\e[0m file: \\e[33;1m${values_files}\\e[0m"

      awkenvsubst < "$values_files" > generated-values.yml

      TBC_ENVSUBST_ENCODING=jsonstr tbc_envsubst "$values_files" > generated-values.yml

      helm_opts="$helm_opts --values generated-values.yml"

    fi

      - VAR_PREFIX: PROD

  script:

    - values_file=$(eval echo "\$HELM_${VAR_PREFIX}_VALUES")

    - awkenvsubst < "$values_file" > generated-values.yml

    - TBC_ENVSUBST_ENCODING=jsonstr tbc_envsubst "$values_file" > generated-values.yml

    - yamllint -d "$HELM_YAMLLINT_CONFIG" $HELM_YAMLLINT_ARGS generated-values.yml

  rules:

    # exclude tags

      - ENV_TYPE: production

        VAR_PREFIX: PROD

  script:

    - awkenvsubst < "${HELM_COMMON_VALUES:-/dev/null}" > generated-values-common.yml

    - TBC_ENVSUBST_ENCODING=jsonstr tbc_envsubst "${HELM_COMMON_VALUES:-/dev/null}" > generated-values-common.yml

    - env_values=$(eval echo "\$HELM_${VAR_PREFIX}_VALUES")

    - awkenvsubst < "$env_values" > generated-values-env.yml

    - TBC_ENVSUBST_ENCODING=jsonstr tbc_envsubst "$env_values" > generated-values-env.yml

    - helm template $helm_package ${HELM_K8S_VERSION:+--kube-version "$HELM_K8S_VERSION"} --values generated-values-common.yml --values generated-values-env.yml | kube-score score ${HELM_K8S_VERSION:+--kubernetes-version "$HELM_K8S_VERSION"} ${HELM_KUBE_SCORE_ARGS} -

  rules:

    # exclude tags