helm

#!/bin/bash

#####
# helm-wrapper tool simplifies helm/tiller version and namespace management.
#
# See https://github.com/cradlepoint/helm-wrapper for installation instructions.
#
#####

set -e # exit on any error

# helper function to scan caller-supplied parameters
isParamSpecified() {
  PARAM=$1
  for P in "${@:2}"; do
    if [ $P == "$PARAM" ]; then
     return 0 # true
    fi
  done
  return 1 # false
}

##############
# Step 1: figure out tiller namespace

# if caller did not specify --tiller-namespace then calculate it
if ! isParamSpecified "--tiller-namespace" $@; then
  # check for TILLER_NAMESPACE env
  if [ -n "$TILLER_NAMESPACE" ]; then
    NS_DEBUG="helm-wrapper: using env TILLER_NAMESPACE $TILLER_NAMESPACE"

  # check kubeconfig namespace
  elif [ ! -z "`kubectl config current-context`" ] ; then
    NS=$(kubectl config view --minify --output 'jsonpath={..namespace}')
    if [ -n "$NS" ]; then
      NS_DEBUG="helm-wrapper: using kubeconfig namespace $NS"
    else
      # use default tiller namespace
      NS_DEBUG="helm-wrapper: using default kube-system namespace"
      NS="kube-system"
    fi
    NS="--tiller-namespace $NS"
  fi
else
  NS_DEBUG="helm-wrapper: using --tiller-namespace"
fi

##############
# Step 2: match tiller version for server calls

# search for commands that require helm and tiller to match
TILLER_COMMANDS=(ls list history get install upgrade delete status)
TILLER_COMMAND_FOUND=false
for COMMAND in "${TILLER_COMMANDS[@]}"; do
  if isParamSpecified $COMMAND $@; then
    TILLER_COMMAND_FOUND=true
    break
  fi
done

HELM_LATEST=$(ls /usr/local/bin/helm-*  | sort -V | tail -1)

if [ "$TILLER_COMMAND_FOUND" == "true" ]; then
  # execute command using helm that matches tiller version

  # output namespace info
  (>&2 echo $NS_DEBUG)

  # get server tiller version
  SERVER_TILLER_VERSION=$(exec $HELM_LATEST $NS version --short | grep Server | sed 's/.*v\(.*\)+.*/\1/')

  if [ -n "$SERVER_TILLER_VERSION" ]; then
      HELM_CURRENT="/usr/local/bin/helm-v$SERVER_TILLER_VERSION"
      if [ -f "$HELM_CURRENT" ]; then
        exec $HELM_CURRENT $NS $@
      else
        (>&2 echo "helm-wrapper: error, helm client version $SERVER_TILLER_VERSION is not installed.")
      fi
  fi
else
  # execute command using latest helm

  # output namespace info for "helm init"
  if isParamSpecified "init" $@; then (>&2 echo $NS_DEBUG) fi

  exec $HELM_LATEST $NS $@
fi