#!/bin/bash
set -x

# Root user required
if [ "$(id -u)" != "0" ]; then
  echo "Sorry, you must be root to install dd-agent" && exit 1
fi

# Python and sysstat are required
if ! command -v python &>/dev/null; then echo "Python not installed" && exit 1; fi
if ! command -v iostat &>/dev/null; then echo "sysstat not installed" && exit 1; fi

# Python must be between 2.6.x and 3.x.x
if ! python -c "import sys; ver = sys.version_info; e = 0 if ver[0] == 2 and ver[1] > 5 else 66; sys.exit(e)"; then
  echo "Python version must be between 2.6.x and 3.x.x" && exit 1
fi

# Command used to grab source files
get() {
  if command -v curl &>/dev/null; then
    wget --no-check-certificate -q -O- $1
  else 
    curl -kfsSL $1
  fi
}

DD_USER=${DD_USER:-datadog}
DD_BASEDIR=${DD_BASEDIR:-/opt/local/dd-agent}
DD_VERSION=${DD_VERSION:-5.3.0}

# Create datadog user if it does not exist
if ! id -u ${DD_USER} &>/dev/null; then
  useradd -d ${DD_BASEDIR} -n -s /sbin/nologin ${DD_USER}
fi

# Base install structure
install -d -o ${DD_USER} ${DD_BASEDIR}/{agent,bin,logs,run,supervisord/logs}
ln -nfs ${DD_BASEDIR}/supervisord/logs ${DD_BASEDIR}/logs/supervisord

# upgrade pip
pip install --upgrade pip

pushd ${DD_BASEDIR}
  # Install & activate virtualenv
  get https://raw.github.com/pypa/virtualenv/1.11.6/virtualenv.py | python - venv
  . venv/bin/activate
  
  pip install --upgrade pip
  pip install supervisor==3.0b2

  # Install dd-agent & the Python source requirements
  get https://github.com/Datadog/dd-agent/tarball/${DD_VERSION} | tar -xz -C agent --strip-components 1
  pip install -r agent/source-requirements.txt
  pip install -r agent/source-optional-requirements.txt

  cp agent/packaging/datadog-agent/source/{agent,info} bin/
  cp agent/packaging/datadog-agent/source/supervisord.conf supervisord/supervisord.conf
  cp agent/datadog.conf.example datadog.conf

  chown -R ${DD_USER}: .
  chmod +x bin/{agent,info}
popd