17.16. donau.conf(5)#

17.16.1. Name#

donau.conf - Donau configuration file

17.16.2. Description#

The configuration file is line-oriented. Blank lines and whitespace at the beginning and end of a line are ignored. Comments start with # or % in the first column (after any beginning-of-line whitespace) and go to the end of the line.

The file is split into sections. Every section begins with [SECTIONNAME] and contains a number of options of the form OPTION=VALUE. There may be whitespace around the = (equal sign). Section names and options are case-insensitive.

The values, however, are case-sensitive. In particular, boolean values are one of YES or NO. Values can include whitespace by surrounding the entire value with " (double quote). Note, however, that there are no escape characters in such strings; all characters between the double quotes (including other double quotes) are taken verbatim.

Values that represent a time duration are represented as a series of one or more NUMBER UNIT pairs, e.g. 60 s, 4 weeks 1 day, 5 years 2 minutes.

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.

Values that represent filenames can begin with a /bin/sh-like variable reference. This can be simple, such as $TMPDIR/foo, or complex, such as ${TMPDIR:-${TMP:-/tmp}}/foo. The variables are expanded either using key-values from the [PATHS] section (see below) or from the environment (getenv()). The values from [PATHS] take precedence over those from the environment. If the variable name is found in neither [PATHS] nor the environment, a warning is printed and the value is left unchanged. Variables (including those from the environment) are expanded recursively, so if FOO=$BAR and BAR=buzz then the result is FOO=buzz. Recursion is bounded to at most 128 levels to avoid undefined behavior for mutually recursive expansions like if BAR=$FOO in the example above.

The [PATHS] section is special in that it contains paths that can be referenced using $ in other configuration values that specify filenames. Note that configuration options that are not specifically retrieved by the application as filenames will not see “$”-expressions expanded. To expand $-expressions when using taler-config, you must pass the -f command-line option.

The system automatically pre-populates the [PATHS] section with a few values at run-time (in addition to the values that are in the actual configuration file and automatically overwriting those values if they are present). These automatically generated values refer to installation properties from GNU autoconf. The values are usually dependent on an INSTALL_PREFIX which is determined by the --prefix option given to configure. The canonical values are:

LIBEXECDIR = $INSTALL_PREFIX/taler/libexec/
DOCDIR = $INSTALL_PREFIX/share/doc/taler/
ICONDIR = $INSTALL_PREFIX/share/icons/
LOCALEDIR = $INSTALL_PREFIX/share/locale/
PREFIX = $INSTALL_PREFIX/
BINDIR = $INSTALL_PREFIX/bin/
LIBDIR = $INSTALL_PREFIX/lib/taler/
DATADIR = $INSTALL_PREFIX/share/taler/

Note that on some platforms, the given paths may differ depending on how the system was compiled or installed, the above are just the canonical locations of the various resources. These automatically generated values are never written to disk.

Files containing default values for many of the options described below are installed under $DONAU_PREFIX/share/donau/config.d/. The configuration file given with -c to Donau binaries overrides these defaults.

A configuration file may include another, by using the @INLINE@ directive, for example, in main.conf, you could write @INLINE@ sub.conf to include the entirety of sub.conf at that point in main.conf.

Be extra careful when using donau-config -V VALUE to change configuration values: it will destroy all uses of @INLINE@ and furthermore remove all comments from the configuration file!

17.16.2.1. GLOBAL OPTIONS#

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

DONAU_HOME: Home directory of the user, usually “${HOME}”. Can be overwritten by testcases by setting ${DONAU_TEST_HOME}.
DONAU_DATA_HOME: Where should Taler store its long-term data. Usually “${DONAU_HOME}/.local/share/donau/”.
DONAU_CONFIG_HOME: Where is the Taler configuration kept. Usually “${DONAU_HOME}/.config/donau/”.
DONAU_CACHE_HOME: Where should Taler store cached data. Usually “${DONAU_HOME}/.cache/donau/”.
DONAU_RUNTIME_DIR: Where should Taler store system runtime data (like UNIX domain sockets). Usually “${TMP}/donau-runtime”.

17.16.2.2. DONAU OPTIONS#

The following options are from the “[donau]” section and used by most Donau components.

ADMIN_BEARER_TOKEN

Bearer access token used to access the REST API to manage charities. Should begin with “secret-token:”.

CURRENCY

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

DB

Plugin to use for the database, e.g. “postgres”.

SERVE

Should the HTTP server listen on a UNIX domain socket (set option to “unix”), or on a TCP socket (set option to “tcp”), or be activated via systemd (set option to “systemd”).

UNIXPATH

Path to listen on if we “SERVE” is set to “unix”.

UNIXPATH_MODE

Access permission mask to use for the “UNIXPATH”.

PORT

Port on which the HTTP server listens, e.g. 8080.

BIND_TO

Hostname to which the exchange HTTP server should be bound to, e.g. “localhost”.

BASE_URL

The base URL under which the exchange can be reached. Added to wire transfers to enable tracking by merchants. Used by the KYC logic when interacting with OAuth 2.0.

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, e.g. “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 (e.g. 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.

17.16.2.3. DONAU RSA CRYPTO HELPER OPTIONS#

The following options must be in the section “[donau-secmod-rsa]”.

LOOKAHEAD_SIGN: How long do we generate denomination and signing keys ahead of time?
OVERLAP_DURATION: Must be set to zero.
SM_PRIV_KEY: Where should the security module store its long-term private key?
KEY_DIR: Where should the security module store the private keys it manages?
UNIXPATH: On which path should the security module listen for signing requests?

Note that the donau-secmod-rsa also evaluates the [doco_*] configuration sections described below.

17.16.2.4. DONAU CS CRYPTO HELPER OPTIONS#

The following options must be in the section “[donau-secmod-cs]”.

LOOKAHEAD_SIGN: How long do we generate denomination and signing keys ahead of time?
OVERLAP_DURATION: Must be set to zero.
SM_PRIV_KEY: Where should the security module store its long-term private key?
KEY_DIR: Where should the security module store the private keys it manages?
UNIXPATH: On which path should the security module listen for signing requests?

Note that the donau-secmod-cs also evaluates the [doco_*] configuration sections described below.

17.16.2.5. DONAU EDDSA CRYPTO HELPER OPTIONS#

The following options must be in the section “[donau-secmod-eddsa]”.

LOOKAHEAD_SIGN: How long do we generate denomination and signing keys ahead of time?
OVERLAP_DURATION: 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.
DURATION: For how long should EdDSA keys be valid for signing?
SM_PRIV_KEY: Where should the security module store its long-term private key?
KEY_DIR: Where should the security module store the private keys it manages?
UNIXPATH: On which path should the security module listen for signing requests?

17.16.2.6. DONAU POSTGRES BACKEND DATABASE OPTIONS#

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

CONFIG: How to access the database, e.g. “postgres:///donau” to use the “donau” database. Testcases use “donaucheck”.

17.16.2.7. EXCHANGE COIN OPTIONS#

The following options must be in sections starting with "[coin_]" and are largely used by taler-exchange-httpd to determine the meta data for the denomination keys. Some of the options are used by the taler-exchange-secmod-rsa to determine which RSA keys to create (and of what key length). Note that the section names must match, so this part of the configuration MUST be shared between the RSA helper and the exchange. Configuration values MUST NOT be changed in a running setup. Instead, if parameters for a denomination type are to change, a fresh section name should be introduced (and the existing section should be deleted).

VALUE: Value of the coin, e.g. “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.
CIPHER: What cryptosystem should be used? Must be set to either “CS” or “RSA”. The respective crypto-helper will then generate the keys for this denomination.
RSA_KEYSIZE: What is the RSA keysize modulos (in bits)? Only used if “CIPHER=RSA”.
AGE_RESTRICTED: Setting this option to YES marks the denomination as age restricted (default is NO). For this option to be accepted the extension for age restriction MUST be enabled.

17.16.2.8. DONAU DONATION CONFIRMATION UNIT OPTIONS#

The following options must be in sections starting with "[doco_]" and are largely used by donau-httpd to determine the meta data for the donation units. Some of the options are used by the donau-secmod-rsa to determine which RSA keys to create (and of what key length). Note that the section names must match, so this part of the configuration MUST be shared between the RSA helper and the Donau. Configuration values MUST NOT be changed in a running setup. Instead, if parameters for a denomination type are to change, a fresh section name should be introduced (and the existing section should be deleted).

VALUE: Value of the coin, e.g. “EUR:1.50” for 1 Euro and 50 Cents (per donation unit receipt).
DURATION_WITHDRAW: How long should the same key be used for clients to withdraw coins of this value? Must be set to 1 year.
DURATION_SPEND: How long do clients have to turn in the donation receipts. Should be set to a multiple of years.
DURATION_LEGAL: How long does the Donau have to keep records for this denomination? Should be set to a multiple of years.
CIPHER: What cryptosystem should be used? Must be set to either “CS” or “RSA”. The respective crypto-helper will then generate the keys for this denomination.
RSA_KEYSIZE: What is the RSA keysize modulos (in bits)? Only used if “CIPHER=RSA”.

17.16.3. SEE ALSO#

donau-dbinit(1), donau-httpd(1)

17.16.4. BUGS#

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

donau.conf(5)

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