mte/src/config.ml

(* https://docs.taler.net/manpages/taler-exchange.conf.5.html
   taler-docs/manpages/taler-exchange.conf.5.rst *)
(* TODO
   - generate `config.ml` from config file (virtual module)?
   - parse config file format
   - no relative path
   - default config: use relevant duration, all set to 1 year for now
   *)

(* ---- *)
let currency = `Eur
let currency_to_string = function `Eur -> "EUR"

(* Values that represent an amount are in the usual amount syntax: CURRENCY:VALUE.FRACTION,
   e.g. EUR:1.50. The FRACTION portion may extend up to 8 places. *)
type value = {
  currency: [ `Eur ];
  value: int;
  fraction: int;
}

let currency_round_unit = { currency= `Eur; value= 0; fraction= 1 }

let value_to_string v =
  Fmt.str "%s:%d.%d" (currency_to_string v.currency) v.value v.fraction

(* https://docs.taler.net/manpages/taler-exchange.conf.5.html#exchange-coin-options *)
module Coin = struct
  (* How much is the coin worth, the format is CURRENCY:VALUE.FRACTION. For
     example, a 10 cent piece is “EUR:0.10”. *)
  let value = { currency= `Eur; value= 0; fraction= 1 }

  (*How long can a coin of this type be withdrawn? This limits the losses
    incurred by the exchange when a denomination key is compromised.*)
  let duration_withdraw = Duration.of_year 1

  (*How long is a coin of the given type valid? Smaller values result in lower
    storage costs for the exchange.*)
  let duration_spend = Duration.of_year 1

  (*How long is the coin of the given type legal?*)
  let duration_legal = Duration.of_year 1

  (*What does it cost to withdraw this coin? Specified using the same format as
    value.*)
  let fee_withdraw = { currency= `Eur; value= 0; fraction= 0 }

  (*What does it cost to deposit this coin? Specified using the same format as
    value.*)
  let fee_deposit = { currency= `Eur; value= 0; fraction= 0 }

  (*What does it cost to refresh this coin? Specified using the same format as
    value.*)
  let fee_refresh = { currency= `Eur; value= 0; fraction= 0 }

  (*What does it cost to refund this coin? Specified using the same format as
    value.*)
  let fee_refund = { currency= `Eur; value= 0; fraction= 0 }

  (*Which cipher to use for this coin? Must be either RSA or CS.*)
  let cipher : [ `RSA | `CS ] = `RSA

  (*How many bits should the RSA modulus (product of the two primes) have for
    this type of coin.*)
  let rsa_keysize = -1

  (*Set to YES to make this a denomination with support*)
  let age_restricted : [ `YES | `NO ] = `NO
end

(* Crockford Base32-encoded master public key, public version of the exchange’s long-time offline signing key. *)
let master_public_key = "uhuh"

(* module type for CS/EDDSA/RSA config *)
module Secmod = struct
  (* Note that the taler-exchange-secmod-rsa also evaluates the [coin_*] configuration sections described below. *)

  (*How long do we generate denomination and signing keys ahead of time?*)
  let lookahead_sign = Duration.of_year 1

  (*How much should validity periods for coins overlap? Should be long enough to avoid problems with wallets picking one key and then due to network latency another key being valid. The DURATION_WITHDRAW period must be longer than this value.*)
  let overlap_duration = Duration.of_year 1

  (*
    Where should the security module store its long-term private key?
SM_PRIV_KEY

    Where should the security module store the private keys it manages?
KEY_DIR

    On which path should the security module listen for signing requests?
UNIXPATH
*)
end

module Database = struct
  (*After which time period should reserves be closed if they are idle?*)
  let idle_reserve_expiration_time = -1

  (*After what time do we forget about (drained) reserves during garbage collection?*)
  let legal_reserve_expiration_time = -1

  (*Delay between a deposit being eligible for aggregation and the aggregator actually triggering.*)
  let aggregator_shift = -1

  (*Number of concurrent purses that a reserve may have active if it is paid to be opened for a year.*)
  let default_purse_limit = -1

  (*Maximum time an AML program is allowed to run. (Optional for taler-auditor.)*)
  let max_aml_program_runtime = -1

  module Postgres = struct
    (*How to access the database, e.g. “postgres:///taler-exchange” to use the “taler-exchange” database. Testcases use “talercheck”.*)
    let config = "uhuh"
  end
end