examples/aqua-examples/price-oracle/aqua/get_crypto_prices.aqua

import "@fluencelabs/aqua-lib/builtin.aqua"

data Result:
  result: f64
  success: bool
  error_msg: string

service PriceGetterService:
  price_getter(coin: string, currency: string, timestamp_ms: u64) -> Result

service MeanService:
  mean(data: []f64) -> Result

service F64Op("op"):
    identity(x:f64) -> f64

data Payload:
    coin: string
    currency: string

data NodeServicePair:
    node: string
    service_id: string

func get_price(coin: string, currency: string, node: string, pg_sid: string, mean_sid: string) -> Result:
    prices: *f64
    on node:
        k <- Op.string_to_b58(node)
        
        PriceGetterService pg_sid
        MeanService mean_sid

        ts_ms0 <- Peer.timestamp_ms()
        res0 <- PriceGetterService.price_getter(coin, currency, ts_ms0)
        -- if price.success:
        prices <- F64Op.identity(res0.result)

        ts_ms1 <- Peer.timestamp_ms()
        res1 <- PriceGetterService.price_getter(coin, currency, ts_ms1)
        -- if price.success:
        prices <- F64Op.identity(res1.result)

        result <- MeanService.mean(prices)
        -- else:
             --    logError("price_getter: ", price.error_msg)
    <- result

func get_price_par(coin: string, currency: string, getter_topo: []NodeServicePair, mean_topo: NodeServicePair) -> Result:
  prices: *f64
  for topo <- getter_topo par:
    on topo.node:        
      PriceGetterService topo.service_id
      ts_ms <- Peer.timestamp_ms()
      res <- PriceGetterService.price_getter(coin, currency, ts_ms)
      prices <- F64Op.identity(res.result)
      Op.noop()

  on mean_topo.node:
    F64Op.identity(prices!1)
    MeanService mean_topo.service_id
    result <- MeanService.mean(prices)
  <- result