cloudformation-functions

#!/bin/bash

# cloudformation-functions.sh
#
# Create, List, Update, Delete (plus diff, tail, etc) CF stacks
#
# Requires awscli (and jq-1.4 or later for cf_diff)
#
# Hint: Naming templates as [stack_name + '.json'] will allow
# you to use tab completion to provide stack name. The functions
# will drop the '.json' if present in the stack argument.

# List CF stacks. Optionally filter on stack name.
# e.g. 
#      cf_list foo
#
# To make it fly we omit stacks with status of DELETE_COMPLETE
cf_list() {
  aws cloudformation list-stacks \
    --stack-status  \
      CREATE_COMPLETE \
      CREATE_FAILED \
      CREATE_IN_PROGRESS \
      DELETE_FAILED \
      DELETE_IN_PROGRESS \
      ROLLBACK_COMPLETE \
      ROLLBACK_FAILED \
      ROLLBACK_IN_PROGRESS \
      UPDATE_COMPLETE \
      UPDATE_COMPLETE_CLEANUP_IN_PROGRESS \
      UPDATE_IN_PROGRESS \
      UPDATE_ROLLBACK_COMPLETE \
      UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS \
      UPDATE_ROLLBACK_FAILED \
      UPDATE_ROLLBACK_IN_PROGRESS \
  --query "StackSummaries[].StackName" \
  --output text | tr '\t' '\n' | sort | grep "$1"
}
alias cf_stacks=cf_list


# Report on what changes would be made to stack by applying template
#
# Requires jq-1.4 or later # http://stedolan.github.io/jq/download/
#
cf_diff() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack [template]"; return 1; fi
  local stack="$(basename $1 .json)"
  if ! aws cloudformation describe-stacks --stack-name $stack 2>/dev/null 1>/dev/null; then 
    echo "Stack: $stack does not exist"
    return 1; 
  fi
  local template="$(cf_template $stack $2)"
  if [ ! -f "$template" ]; then
    echo "Could not find ${stack}.json. You can specify alternative template as second argument."
    return 1
  fi
  if [ "x$( type -P colordiff )" != "x" ]; then
    local DIFF_CMD=colordiff
  else
    local DIFF_CMD=diff
  fi
  $DIFF_CMD -u <(aws cloudformation get-template  --stack-name $stack --query TemplateBody | jq --sort-keys .) <(jq --sort-keys . $template)
  if [ $? -eq 0 ]; then
    echo "no difference"
  fi
}

# Show all events for CF stack until update completes or fails.
cf_tail() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  local current
  local final_line
  local output
  local previous
  until echo "$current" | tail -1 | egrep -q "${stack}.*_(COMPLETE|FAILED)"
  do
    if ! output=$(cf_events $stack); then
      # Something went wrong with cf_events (like stack not known)
      return 1
    fi
    if [ -z "$output" ]; then sleep 1; continue; fi

    current=$(echo "$output" | sed '$d')
    final_line=$(echo "$output" | tail -1)
    if [ -z "$previous" ]; then
      echo "$current"
    elif [ "$current" != "$previous" ]; then
      comm -13 <(echo "$previous") <(echo "$current")
    fi
    previous="$current"
    sleep 1
  done
  echo $final_line
}

cf_events() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  shift
  local output
  if output=$(aws cloudformation describe-stack-events --stack-name $stack --query 'sort_by(StackEvents, &Timestamp)[].{Resource: LogicalResourceId, Type: ResourceType, Status: ResourceStatus}' --output table $@); then
    echo "$output" | uniq -u
  else
    return $?
  fi
}

cf_status() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  aws cloudformation describe-stacks --stack-name "$stack" --query "Stacks[0].StackStatus" --output text
}

cf_get() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  aws cloudformation get-template --stack-name $stack --query TemplateBody
}

cf_template() {
  local stack="$(basename $1 .json)"
  local template=$2
  if [ -z "$template" ]; then
    if [ -f "${stack}.json" ]; then
      template="${stack}.json"
    elif [ -f "${stack%-*}.json" ]; then
      template="${stack%-*}.json"
    fi
  fi
  echo $template
}

cf_create() {
  # XXX accept params from arguments
  # XXX show account_alias_or_id
  # XXX confirm if not -f
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack [template-file] [params-file]"; return 1; fi
  local stack="$(basename $1 .json)"
  local template="$(cf_template $stack $2)"
  if [ ! -f "$template" ]; then
    echo "Could not find ${stack}.json. You can specify alternative template as second argument."
    return 1
  fi
  if [ -n "$3" ] ; then
    local parameters="--parameters file://$3";
  fi
  if aws cloudformation create-stack --stack-name $stack --template-body file://$template $parameters --capabilities CAPABILITY_IAM --disable-rollback
  then
    cf_tail $stack
  fi
}

cf_update() {
  # XXX accept params from arguments
  # XXX show diff
  # XXX show account_alias_or_id
  # XXX confirm if not -f
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack [template-file] [params-file]"; return 1; fi
  local stack="$(basename $1 .json)"
  local template="$(cf_template $stack $2)"
  if [ ! -f "$template" ]; then
    echo "Could not find ${stack}.json. You can specify alternative template as second argument."
    return 1
  fi
  if [ -n "$3" ] ; then local parameters="--parameters file://$3"; fi
  if aws cloudformation update-stack --stack-name $stack --template-body file://$template $parameters --capabilities CAPABILITY_IAM
  then
    cf_tail $stack
  fi
}

cf_delete() {
  # XXX confirm if not -f
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  if aws cloudformation delete-stack --stack-name $stack
  then
    cf_tail $stack
  fi
}

cf_outputs() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  shift
  aws cloudformation describe-stacks --stack-name $stack --query 'Stacks[].Outputs[]' --output table $@
}

cf_resources() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  shift
  aws cloudformation describe-stack-resources --stack-name $stack --query "StackResources[].{LogicalResourceId: LogicalResourceId, PhysicalResourceId: PhysicalResourceId}" --output table $@
}

cf_validate() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME cf-template-file"; return 1; fi
  aws cloudformation validate-template --template-body file://$1
}

# Show reasons for stack failure
cf_failure() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  aws cloudformation describe-stack-events --stack-name $stack --query 'StackEvents[?contains(ResourceStatus,`FAILED`)].[LogicalResourceId, ResourceStatus, ResourceType, ResourceStatusReason]'
}

cf_params() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  aws cloudformation describe-stacks --query "Stacks[].Parameters[]" --stack-name $stack | jq --sort-keys .
}

# Shows current value of particular parameter in a stack
cf_param() {
  if [ -z "$2" ] ; then echo "Usage: $FUNCNAME stack parameter"; return 1; fi
  local stack="$(basename $1 .json)"
  local param=$2
  aws cloudformation describe-stacks --query "Stacks[].Parameters[?ParameterKey==\`$2\`].ParameterValue" --stack-name $stack --output text
}

##
## Functions to work with stack resources
##

cf_asg() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  aws cloudformation describe-stack-resources --stack-name $stack --query "StackResources[?ResourceType==\`AWS::AutoScaling::AutoScalingGroup\`].PhysicalResourceId" --output text
}

cf_asg_instances() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack"; return 1; fi
  local stack="$(basename $1 .json)"
  local instance_ids="$(aws autoscaling describe-auto-scaling-groups --auto-scaling-group-names "$(cf_asg $stack)" --query "AutoScalingGroups[].Instances[].[InstanceId]" --output text)"
  aws ec2 describe-instances --instance-ids $instance_ids --query "Reservations[].Instances[].[PrivateIpAddress, PublicIpAddress, InstanceId, State.Name, InstanceType, join(\` \`, [Tags[?Key==\`Name\`].Value][])]" --output text
}

cf_asg_instance_ssh() {
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack [user]"; return 1; fi
  local stack="$(basename $1 .json)"
  local user=${2:-root}
  local instance_ip="$(cf_asg_instances $stack | head -1 | cut -f 1)"
  ssh ${user}@${instance_ip}
}

## Start instance
cf_asg_scale_up() {
  # XXX don't scale down
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack [desired_capacity]"; return 1; fi
  local stack="$(basename $1 .json)"
  if [ -n "$2" ]; then
    local desired_capacity="$2"
  else
    local desired_capacity="$(cf_param $stack desiredCapacity)"
  fi
  if [ -z "$desired_capacity" ]; then
    local desired_capacity=1
  fi
  local asg_name="$(cf_asg $stack)"
  echo "Scaling up AutoScalingGroup [$asg_name] to [$desired_capacity] instances"
  aws autoscaling set-desired-capacity --auto-scaling-group-name $asg_name --desired-capacity $desired_capacity
}

## Stop Instance
cf_asg_scale_down() {
  # XXX don't scale up
  if [ -z "$1" ] ; then echo "Usage: $FUNCNAME stack [desired_capacity]"; return 1; fi
  local stack="$(basename $1 .json)"
  local desired_capacity="${2:-0}"
  local instances="$(cf_asg_instances $stack | cut -f 3)"
  if [ -n "$instances" ]; then
    aws autoscaling set-desired-capacity --auto-scaling-group-name "$(cf_asg $stack)" --desired-capacity $desired_capacity
    echo -n "Waiting for instances to terminate ($instances)..."
    aws ec2 wait instance-terminated --instance-ids $instances
    echo "Done"
  else
    echo "No running instances found for AutoScalingGroup $stack"
  fi
}