Ansible dynamic inventory script to pull GCE hosts

gce-inventory

#!/usr/bin/env bash

set -e

usage() {
  echo 'Usage: gce-inventory [--help|--list|--host HOSTNAME]' 1>&2
}

LIST_MODE=true
LOOKUP_HOST=

case "$1" in
--list) :;;
--host)
  LIST_MODE=false
  LOOKUP_HOST="$2"
  ;;
-h|--help)
  usage
  exit 2
  ;;
?*)
  echo "Unrecognized argument: $1"
  exit 1
  ;;
'') :;;
esac

# Drop all arguments
set --

lower() {
  echo "$@" | tr '[:upper:]' '[:lower:]'
}

tobool() {
  case "$(lower "$1")" in
  true|t|1|yes|y) echo true;;
  false|f|0|no|n) echo false;;
  *) echo "${2:-false}";;
  esac
}

: "${PROJECT_ID:=$(gcloud config get-value core/project)}"
SELECT_INTERNAL_IP="$(tobool "$SELECT_INTERNAL_IP" false)"

: "${INVENTORY_CONFIG:=gce-inventory.conf}"
[ -r "$INVENTORY_CONFIG" ] && . "$INVENTORY_CONFIG"

if [ "$LIST_MODE" = true ]; then
  if [ -n "$FILTER" ]; then
    set -- "$@" --filter="$FILTER"
  fi
  gcloud --project="$PROJECT_ID" compute instances list --format=json "$@"
else
  LOOKUP_HOST="name='${LOOKUP_HOST}'"
  if [ -n "FILTER" ]; then
    set -- "$@" --filter="(${FILTER}) AND (${LOOKUP_HOST})"
  else
    set -- "$@" --filter="$LOOKUP_HOST" "$@"
  fi
  gcloud --project="$PROJECT_ID" compute instances list --format=json "$@"
fi |
  jq -c \
     --argjson internalIPs "$SELECT_INTERNAL_IP" \
     --argjson listMode    "$LIST_MODE"          \
     --arg     projectID   "$PROJECT_ID"         \
    '
    select(. != []) |
    # Simplify zone, extract region for only hosts with network interfaces
    map(
      select(.status == "RUNNING") |
      select((.networkInterfaces // []) != []) |
      select(
        if $internalIPs then
          try (.networkInterfaces[0].networkIP != "") catch false
        else
          try (.networkInterfaces[0].accessConfigs[0].natIP != "") catch false
        end
      ) |
      .__orig = . |
      .machineType |= (split("/") | last) |
      .zone |= (split("/") | last) |
      .region = (.zone | split("-")[:-1] | join("-")) |
      .network = (.networkInterfaces[0].network | split("/") | last) |
      .subnetwork = (.networkInterfaces[0].subnetwork | split("/") | last) |
      .externalIP = ((.networkInterfaces[0].accessConfigs[0].natIP) // null) |
      .internalIP = ((.networkInterfaces[0].networkIP) // null) |
      .tags |= (.items // [])
    ) |
    . as $hosts |

    # Host vars
    ($hosts | map(
      {
        (.name): {
          ansible_host: (if $internalIPs then .internalIP else .externalIP end),
          gce_id: (try .id),
          gce_name: (try .name),
          gce_status: (try .status),
          gce_machine_type: (try .machineType),
          gce_description: (try .description),
          gce_zone: (try .zone),
          gce_region: (try .region),
          gce_tags: (try .tags),
          gce_network: (try .network),
          gce_subnetwork: (try .subnetwork),
          gce_public_ip: (try .externalIP),
          gce_private_ip: (try .internalIP),
          gce_service_account: (try (.serviceAccounts[0].email)),
          gce_metadata: (.metadata.items // [] | from_entries),
          gce_instance: .__orig
        }
      }
    ) | add) as $hostvars |

    if $listMode then (
      # Network tags
      ($hosts | map(try (.tags[])) | flatten | sort | unique |
        map(
          . as $tag |
          { "tag_\(.)": { hosts: ($hosts | map(select(.tags | contains([$tag])).name)) } }
        ) | add
      ) as $tagged |

      # Zonal groups
      ($hosts | group_by(.zone) | map(
        { (first.zone): { hosts: map(.name) } }
      ) | add) as $zonal |

      # Regional groups
      ($hosts | group_by(.region) | map(
        { (first.region): { hosts: map(.name) } }
      ) | add) as $regional |

      ($regional + $zonal + $tagged) as $grouped |
      (($grouped | map(.hosts[]) | sort | unique) as $groupedHostnames |
        $hosts | map(.name | select(. as $name | $groupedHostnames | contains([$name]) | not))) as $ungrouped |
      $grouped + {
        ($projectID): { hosts: ($hosts | map(.name)), children: ($grouped | keys) },
        ungrouped: { hosts: $ungrouped },
        all: { children: [($grouped | keys[]), "ungrouped"] },
        _meta: { hostvars: $hostvars }
      }
    ) else (
      $hostvars[]
    ) end
    '