16.21. taler.conf(5)

16.21.1. Name

taler.conf - Taler configuration file

16.21.2. Description

The basic structure of the configuration file is the following. The file is split into sections. Every section begins with “[SECTIONNAME]” and contains a number of options of the form “OPTION=VALUE”. Empty lines and lines beginning with a “#” are treated as comments. Files containing default values for many of the options described below are installed under $TALER_PREFIX/share/taler/config.d/. The configuration file given with -c to Taler binaries overrides these defaults.

Global Options

The following options are from the “[taler]” section and used by virtually all Taler components.

CURRENCY
Name of the currency, i.e. “EUR” for Euro.

The “[PATHS]” section is special in that it contains paths that can be referenced using “$” in other configuration values that specify filenames. For Taler, it commonly contains the following paths:

TALER_HOME
Home directory of the user, usually “${HOME}”. Can be overwritten by testcases by setting ${TALER_TEST_HOME}.
TALER_DATA_HOME
Where should Taler store its long-term data. Usually “${TALER_HOME}/.local/share/taler/”
TALER_CONFIG_HOME
Where is the Taler configuration kept. Usually “${TALER_HOME}/.config/taler/”
TALER_CACHE_HOME
Where should Taler store cached data. Usually “${TALER_HOME}/.cache/taler/”
TALER_RUNTIME_DIR
Where should Taler store system runtime data (like UNIX domain sockets). Usually “${TMP}/taler-system-runtime”.

EXCHANGE OPTIONS

The following options are from the “[exchange]” section and used by most exchange tools.

DB
Plugin to use for the database, i.e. “postgres”
PORT
Port on which the HTTP server listens, i.e. 8080.
MASTER_PUBLIC_KEY
Crockford Base32-encoded master public key, public version of the exchange´s long-time offline signing key.
MASTER_PRIV_FILE
Location of the master private key on disk. Only used by tools that can be run offline (as the master key is for offline signing).
BASE_URL
Specifies the base URL under which the exchange can be reached. Added to wire transfers to enable tracking by merchants.
AGGREGATOR_IDLE_SLEEP_INTERVAL
For how long should the aggregator sleep when it is idle before trying to look for more work? Default is 60 seconds.
SIGNKEY_DURATION
For how long is a signing key valid?
LEGAL_DURATION
For how long are signatures with signing keys legally valid?
LOOKAHEAD_SIGN
How long do we generate denomination and signing keys ahead of time?
LOOKAHEAD_PROVIDE
How long into the future do we provide signing and denomination keys to clients?
TERMS_DIR
Directory where the terms of service of the exchange operator can be fund. The directory must contain sub-directories for every supported language, using the two-character language code in lower case, i.e. “en/” or “fr/”. Each subdirectory must then contain files with the terms of service in various formats. The basename of the file of the current policy must be specified under TERMS_ETAG. The extension defines the mime type. Supported extensions include “html”, “htm”, “txt”, “pdf”, “jpg”, “jpeg”, “png” and “gif”. For example, using a TERMS_ETAG of “0”, the structure could be the following:
  • $TERMS_DIR/en/0.pdf
  • $TERMS_DIR/en/0.html
  • $TERMS_DIR/en/0.txt
  • $TERMS_DIR/fr/0.pdf
  • $TERMS_DIR/fr/0.html
  • $TERMS_DIR/de/0.txt
TERMS_ETAG
Basename of the file(s) in the TERMS_DIR with the current terms of service. The value is also used for the “Etag” in the HTTP request to control caching. Whenever the terms of service change, the TERMS_ETAG MUST also change, and old values MUST NOT be repeated. For example, the date or version number of the terms of service SHOULD be used for the Etag. If there are minor (i.e. spelling) fixes to the terms of service, the TERMS_ETAG probably SHOULD NOT be changed. However, whenever users must approve the new terms, the TERMS_ETAG MUST change.
PRIVACY_DIR
Works the same as TERMS_DIR, just for the privacy policy.
PRIVACY_ETAG
Works the same as TERMS_ETAG, just for the privacy policy.

EXCHANGE DATABASE OPTIONS

The following options must be in the section “[exchangedb]”.

DURATION_OVERLAP
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.
IDLE_RESERVE_EXPIRATION_TIME
After which time period should reserves be closed if they are idle?
LEGAL_RESERVE_EXPIRATION_TIME
After what time do we forget about (drained) reserves during garbage collection?

EXCHANGE POSTGRES BACKEND DATABASE OPTIONS

The following options must be in section “[exchangedb-postgres]” if the “postgres” plugin was selected for the database.

CONFIG
How to access the database, i.e. “postgres:///taler” to use the “taler” database. Testcases use “talercheck”.

EXCHANGE ACCOUNT OPTIONS

An exchange (or merchant) can have multiple bank accounts. The following options are for sections named “[exchange-account-SOMETHING]”. The SOMETHING is arbitrary and should be chosen to uniquely identify the bank account for the operator.

PAYTO_URI
Specifies the payto://-URL of the account. The general format is payto://$METHOD/$DETAILS. Examples: payto://x-taler-bank/localhost:8899/Exchange or payto://iban/GENODEF1SLR/DE67830654080004822650/ or payto://iban/DE67830654080004822650/ (providing the BIC is optional).
WIRE_GATEWAY_URL
URL of the wire gateway. Typically of the form https://$HOSTNAME[:$PORT]/taler-wire-gateway/$USERNAME/ where $HOSTNAME is the hostname of the system running the bank (such as the Taler Python bank or the Nexus) and $USERNAME is the username of the exchange’s bank account (usually matching the USERNAME option used for authentication). Example: https://bank.demo.taler.net/taler-wire-gateway/Exchange/
WIRE_GATEWAY_AUTH_METHOD
This option determines how the exchange (auditor/wirewatch/aggregator) authenticates with the wire gateway. Choices are basic and none.
USERNAME
User name for basic authentication with the wire gateway.
PASSWORD
Password for basic authentication with the wire gateway.
WIRE_RESPONSE
Specifies the name of the file in which the /wire response for this account should be located. Used by the Taler exchange service and the taler-exchange-wire tool. Example: ${TALER_DATA_HOME}/exchange/wire-sigs/SOMETHING.json. Note that the file names must differ between all of the exchange bank accounts. It is suggested to use the section name for SOMETHING to ensure uniqueness.
ENABLE_DEBIT
Must be set to YES for the accounts that the taler-exchange-aggregator and taler-exchange-closer should debit.
ENABLE_CREDIT
Must be set to YES for the accounts that the taler-exchange-wirewatch should check for credits. It is yet uncertain if the merchant implementation may check this flag as well.

EXCHANGE WIRE FEE OPTIONS

For each supported wire method (i.e. “x-taler-bank” or “sepa”), sections named “[fees-METHOD]” state the (aggregate) wire transfer fee and the reserve closing fees charged by the exchange. Note that fees are specified using the name of the wire method, not by the plugin name. You need to replace “YEAR” in the option name by the calendar year for which the fee should apply. Usually, fees should be given for several years in advance.

WIRE-FEE-YEAR
Aggregate wire transfer fee merchants are charged in YEAR. Specified as a Taler amount using the usual amount syntax (CURRENCY:VALUE.FRACTION).
CLOSING-FEE-YEAR
Reserve closing fee customers are charged in YEAR. Specified as a Taler amount using the usual amount syntax (CURRENCY:VALUE.FRACTION).

EXCHANGE COIN OPTIONS

The following options must be in sections starting with "[coin_]" and are used by taler-exchange-keyup to create denomination keys.

VALUE
Value of the coin, i.e. “EUR:1.50” for 1 Euro and 50 Cents (per coin).
DURATION_WITHDRAW
How long should the same key be used for clients to withdraw coins of this value?
DURATION_SPEND
How long do clients have to spend these coins?
DURATION_LEGAL
How long does the exchange have to keep records for this denomination?
FEE_WITHDRAW
What fee is charged for withdrawal?
FEE_DEPOSIT
What fee is charged for depositing?
FEE_REFRESH
What fee is charged for refreshing?
FEE_REFUND
What fee is charged for refunds? When a coin is refunded, the deposit fee is returned. Instead, the refund fee is charged to the customer.
RSA_KEYSIZE
What is the RSA keysize modulos (in bits)?

MERCHANT OPTIONS

The following options are from the “[merchant]” section and used by the merchant backend.

DB
Plugin to use for the database, i.e._“postgres”
PORT
Port on which the HTTP server listens, i.e. 8080.
LEGAL_PRESERVATION
How long do we keep data in the database for tax audits after the transaction has completed? Default is 10 years.
FORCE_AUDIT
Force the merchant to report every transaction to the auditor (if the exchange has an auditor). Default is NO. Do not change except for testing.

MERCHANT POSTGRES BACKEND DATABASE OPTIONS

The following options must be in section “[merchantdb-postgres]” if the “postgres” plugin was selected for the database.

CONFIG
How to access the database, i.e. “postgres:///taler” to use the “taler” database. Testcases use “talercheck”.

KNOWN EXCHANGES (for merchants)

The merchant configuration can include a list of known exchanges if the merchant wants to specify that certain exchanges are explicitly trusted. For each trusted exchange, a section [merchant-exchange-$NAME] must exist, where $NAME is a merchant-given name for the exchange. The following options must be given in each “[exchange-$NAME]” section.

EXCHANGE_BASE_URL
Base URL of the exchange, i.e. “https://exchange.demo.taler.net/
MASTER_KEY
Crockford Base32 encoded master public key, public version of the exchange´s long-time offline signing key. Can be omitted, in that case the exchange will NOT be trusted unless it is audited by a known auditor. Omitting the MASTER_KEY can be useful if we do not trust the exchange without an auditor, but should pre-load the keys of this particular exchange on startup instead of waiting for it to be required by a client.
CURRENCY
Name of the currency for which this exchange is used, i.e. “KUDOS”. The entire section is ignored if the currency does not match the currency we use, which must be given in the [taler] section.

KNOWN AUDITORS (for merchants)

The merchant configuration can include a list of known exchanges if the merchant wants to specify that certain auditors are explicitly trusted. For each trusted exchange, a section [merchant-auditor-$NAME] must exist, where $NAME is a merchant-given name for the auditor. The following options must be given in each “[merchant-auditor-$NAME]” section.

AUDITOR_BASE_URL
Base URL of the auditor, i.e. “https://auditor.demo.taler.net/
AUDITOR_KEY
Crockford Base32 encoded auditor public key.
CURRENCY
Name of the currency for which this auditor is trusted, i.e. “KUDOS” The entire section is ignored if the currency does not match the currency we use, which must be given in the [taler] section.

AUDITOR OPTIONS

The following options must be in section “[auditor]” for the Taler auditor.

DB
Plugin to use for the database, i.e. “postgres”
AUDITOR_PRIV_FILE
Name of the file containing the auditor’s private key

AUDITOR POSTGRES BACKEND DATABASE OPTIONS

The following options must be in section “[auditordb-postgres]” if the “postgres” plugin was selected for the database.

CONFIG
How to access the database, i.e. “postgres:///taler” to use the “taler” database. Testcases use “talercheck”.

16.21.3. SEE ALSO

taler-exchange-dbinit(1), taler-exchange-httpd(1), taler-exchange-keyup(1), taler-exchange-wire(1).

16.21.4. BUGS

Report bugs by using https://bugs.taler.net/ or by sending electronic mail to <taler@gnu.org>.