utils

#!/bin/bash

readonly state_ok=0
readonly state_warning=1
readonly state_critical=2
readonly state_unknown=3

# Set `oc` location
# dynamically locate `oc` with which, but if that fails fall back
# to static location of /usr/bin/oc
if which oc >> /dev/null 2>&1; then
  readonly OPENSHIFT_CLIENT_BINARY=$(which oc)
else
  readonly OPENSHIFT_CLIENT_BINARY=/usr/bin/oc
fi

#
# Print arguments joined by delimiter
#
# Arguments:
# - delim: Delimiter; may have multiple characters
# - args...: Values
#
# Source: https://stackoverflow.com/a/17841619
#
join_args() {
  local delim="$1"; shift
  if [[ "$#" -gt 0 ]]; then
    echo -n "$1"; shift
    if [[ "$#" -gt 0 ]]; then
      printf "%s" "${@/#/$delim}"
    fi
  fi
}

#
# Check whether the arguments are integers
#
validate_integer() {
  for i; do
    if ! [[ "$i" =~ ^-?[0-9]+$ ]]; then
      echo "\"$i\" not recognized as an integer" >&2
      return 1
    fi
  done

  return 0
}

#
# Sort arguments into array variable given as first argument
#
# Arguments:
# - var: Name of output variable
# - args...: Values
#
# Source: https://stackoverflow.com/a/7442583
#
array_sort() {
  local var="$1"; shift

  readarray -t "$var" < <(printf '%s\0' "$@" | LC_ALL=C sort -z | xargs -0n1)
}

#
# Copy unique arguments into array variable given as first argument. The input
# elements must be sorted.
#
# Arguments:
# - var: Name of output variable
# - args...: Values
#
array_uniq() {
  local var="$1"; shift

  readarray -t "$var" < <(printf '%s\0' "$@" | LC_ALL=C uniq -z | xargs -0n1)
}

#
# Subtract matching elements in second array from first array and store
# the result into array variable given as first argument (var = b - a).
# The input arrays must be sorted. Elements must not contain newline
# characters.
#
# Arguments:
# - var: Name of output variable
# - a: Name of first input array
# - b: Name of second input array
#
# Source: https://unix.stackexchange.com/a/104848
#
array_sub() {
  # Use indirect referencing with array, see <https://stackoverflow.com/a/4582492>
  local var="$1" a="$2[@]" b="$3[@]"

  readarray -t "$var" < <(comm -13 <(printf '%s\n' ${!a+"${!a}"}) <(printf '%s\n' ${!b+"${!b}"}))
}

#
# Compute common elements between two arrays and store the result into array
# variable given as first argument (var = b & a). The input arrays must be
# sorted. Elements must not contain newline characters.
#
# Arguments:
# - var: Name of output variable
# - a: Name of first input array
# - b: Name of second input array
#
array_and() {
  # Use indirect referencing with array, see <https://stackoverflow.com/a/4582492>
  local var="$1" a="$2[@]" b="$3[@]"

  readarray -t "$var" < <(comm -12 <(printf '%s\n' ${!a+"${!a}"}) <(printf '%s\n' ${!b+"${!b}"}))
}

#
# Merge exit status
#
# Warning wins over OK, critical wins over warning
#
# Arguments:
# - Current value
# - Desired value
#
merge_status() {
  local cur="$1" update="$2"

  if (( cur < update )); then
    echo "$update"
  else
    echo "$cur"
  fi
}

run_oc() {
  local cfgfile="$1"; shift

  # See https://github.com/openshift/origin/issues/9581
  HOME=/ \
  "$OPENSHIFT_CLIENT_BINARY" \
    --config="$cfgfile" \
    --namespace=default \
    "$@"
}

#
# Print result in Nagios-compatible format and terminate process
#
# Arguments:
# - exit_status: Status code
# - output: Human-readable output
# - metrics: Metrics for Nagios-compatible monitoring systems
#
finish() {
  local exit_status="$1"
  local output="$2"
  local metrics="$3"
  local prefix=UNKNOWN

  case "$exit_status" in
    $state_ok)
      prefix=OK
      ;;
    $state_warning)
      prefix=WARNING
      ;;
    $state_critical)
      prefix=CRITICAL
      ;;
    *)
      exit_status=$state_unknown
      ;;
  esac

  echo "$prefix${output:+ $output}${metrics:+ | $metrics}"
  exit "$exit_status"
}

#
# Determine Kubernetes version
#
get_kube_ver() {
  # oc >= 4 has `oc version -o json` however oc <= 3 does not
  # so we need to parse stdout to figure out what version is being used
  oc_ver_out=$(run_oc "$opt_cfgfile" version)
  if echo "${oc_ver_out}" | grep -q 'kubernetes'; then
    # OpenShift 3 formatting
    kube_major_ver=$(echo "${oc_ver_out}" | grep 'kubernetes' | cut -d' ' -f 2 | cut -d'v' -f 2 | cut -d'+' -f 1 | tail -n1 | cut -d'.' -f 1)
    export kube_major_ver
    kube_minor_ver=$(echo "${oc_ver_out}" | grep 'kubernetes' | cut -d' ' -f 2 | cut -d'v' -f 2 | cut -d'+' -f 1 | tail -n1 | cut -d'.' -f 2)
    export kube_minor_ver
  elif echo "${oc_ver_out}" | grep -q 'Kubernetes Version'; then
    # OpenShift 4 formatting
    kube_major_ver=$(echo "${oc_ver_out}" | grep 'Kubernetes' | cut -d' ' -f 3 | cut -d'v' -f 2 | cut -d'+' -f 1 | tail -n1 | cut -d'.' -f 1)
    export kube_major_ver
    kube_minor_ver=$(echo "${oc_ver_out}" | grep 'Kubernetes' | cut -d' ' -f 3 | cut -d'v' -f 2 | cut -d'+' -f 1 | tail -n1 | cut -d'.' -f 2)
    export kube_minor_ver
  else
    output+=( "Could not determine Kubernetes version" )
    exit_status=$(merge_status "$exit_status" "$state_critical")
  fi
}

# vim: set sw=2 sts=2 et :