construct-connection-strings.sh

#!/usr/bin/env sh
# Constructs Redis and MongoDB connection strings based on environment variables

############################
       ### REDIS ###
############################

# Detect mode
REDIS_MODE="${REDIS_MODE:-standalone}"

# Only construct if URLs not already set
if [ -z "$REDIS_URL" ] || [ -z "$CELERY_BROKER_URL" ]; then

  if [ "$REDIS_MODE" = "replication" ]; then
    # Sentinel HA mode
    echo "Redis mode: Sentinel HA"

    REDIS_SENTINEL_SERVICE="${REDIS_SENTINEL_SERVICE:-snmp-redis-sentinel}"
    REDIS_HEADLESS_SERVICE="${REDIS_HEADLESS_SERVICE:-snmp-redis-headless}"
    REDIS_SENTINEL_PORT="${REDIS_SENTINEL_PORT:-26379}"
    REDIS_PORT="${REDIS_PORT:-6379}"
    REDIS_MASTER_NAME="${REDIS_MASTER_NAME:-mymaster}"
    REDIS_DB="${REDIS_DB:-1}"
    CELERY_DB="${CELERY_DB:-0}"

    if [ -n "$REDIS_PASSWORD" ]; then
      SENTINEL_SCHEME="sentinel://:${REDIS_PASSWORD}@${REDIS_SENTINEL_SERVICE}:${REDIS_SENTINEL_PORT}"
      REDIS_HA_CHECK="redis://:${REDIS_PASSWORD}@${REDIS_HEADLESS_SERVICE}:${REDIS_PORT}"
    else
      SENTINEL_SCHEME="sentinel://${REDIS_SENTINEL_SERVICE}:${REDIS_SENTINEL_PORT}"
      REDIS_HA_CHECK="redis://${REDIS_HEADLESS_SERVICE}:${REDIS_PORT}"
    fi

    REDBEAT_SCHEME="redis-sentinel://${REDIS_SENTINEL_SERVICE}:${REDIS_SENTINEL_PORT}"

    # Celery broker uses sentinel://
    : "${CELERY_BROKER_URL:=${SENTINEL_SCHEME}/${CELERY_DB}#master_name=${REDIS_MASTER_NAME}}"

    # RedBeat uses redis-sentinel:// with master_name query
    : "${REDIS_URL:=${REDBEAT_SCHEME}/${REDIS_DB}#master_name=${REDIS_MASTER_NAME}}"
    SENTINEL_CHECK="redis://${REDIS_SENTINEL_SERVICE}:${REDIS_SENTINEL_PORT}"

    # Checking specific databases
    REDIS_HA_DB_0="${REDIS_HA_CHECK}/${REDIS_DB}"
    REDIS_HA_DB_1="${REDIS_HA_CHECK}/${CELERY_DB}"
    # For healthcheck / wait-for-dep - space-separated list
    REDIS_DEPENDENCIES="${SENTINEL_CHECK} ${REDIS_HA_CHECK} ${REDIS_HA_DB_0} ${REDIS_HA_DB_1}"

  else
    # Standalone mode
    echo "Redis mode: Standalone"
    REDIS_HOST="${REDIS_HOST:-snmp-redis}"
    REDIS_PORT="${REDIS_PORT:-6379}"

    if [ -n "$REDIS_PASSWORD" ]; then
      BASE="redis://:$REDIS_PASSWORD@$REDIS_HOST:$REDIS_PORT"
    else
      BASE="redis://$REDIS_HOST:$REDIS_PORT"
    fi

    : "${REDIS_URL:=$BASE/${REDIS_DB:-1}}"
    : "${CELERY_BROKER_URL:=$BASE/${CELERY_DB:-0}}"

    # For healthcheck / wait-for-dep - space-separated list
    REDIS_DEPENDENCIES="${REDIS_URL} ${CELERY_BROKER_URL}"
  fi

############################
      ### MongoDB ###
############################

  # Build MongoDB URI from environment variables
  if [ -n "$MONGODB_PASSWORD" ]; then
    # With authentication
    if [ -n "$MONGODB_REPLICA_SET" ]; then
      # Replica set
      export MONGO_URI="mongodb://${MONGODB_USERNAME}:${MONGODB_PASSWORD}@${MONGODB_HOST}/${MONGODB_DATABASE}?replicaSet=${MONGODB_REPLICA_SET}&authSource=${MONGODB_AUTH_SOURCE:-admin}&readPreference=primary"
    else
      # Standalone
      export MONGO_URI="mongodb://${MONGODB_USERNAME}:${MONGODB_PASSWORD}@${MONGODB_HOST}:${MONGODB_PORT}/${MONGODB_DATABASE}?authSource=admin"
    fi
  else
    # Without authentication
    if [ -n "$MONGODB_REPLICA_SET" ]; then
      export MONGO_URI="mongodb://${MONGODB_HOST}/${MONGODB_DATABASE}?replicaSet=${MONGODB_REPLICA_SET}&authSource=admin&retryWrites=false&readPreference=primary"
    else
      export MONGO_URI="mongodb://${MONGODB_HOST}:${MONGODB_PORT}/${MONGODB_DATABASE}?authSource=admin"
    fi
  fi

  if [ -n "$MONGODB_REPLICA_SET" ]; then
    export MONGO_WAIT="mongodb://${MONGODB_HOST}/${MONGODB_DATABASE}?replicaSet=${MONGODB_REPLICA_SET}&authSource=admin&retryWrites=false"
  else
    export MONGO_WAIT="mongodb://${MONGODB_HOST}:${MONGODB_PORT}/${MONGODB_DATABASE}?authSource=admin"
  fi

  export MONGO_WAIT
  export MONGO_URI
  export REDIS_URL
  export CELERY_BROKER_URL
  export REDIS_DEPENDENCIES
  export REDIS_MODE

fi