15.6. challenger.conf(5)

15.6.1. Name

challenger.conf - Challenger configuration file

15.6.2. 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/



  • 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 $PREFIX/share/challenger/config.d/. The configuration file given with -c to Challenger 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 challenger-config -V VALUE to change configuration values: it will destroy all uses of @INLINE@ and furthermore remove all comments from the configuration file! GLOBAL OPTIONS

The following options are from the “[challenger]” section. This is normally the only section in a challenger.conf file.


This can either be tcp or unix.


Port on which the HTTP server listens, e.g. 9967. Only used if SERVE is tcp.


Which IP address should we bind to? E.g. or ::1 for loopback. Can also be given as a hostname. We will bind to the wildcard (dual-stack) if left empty. Only used if SERVE is tcp.


Which unix domain path should we bind to? Only used if SERVE is unix.


What should be the file access permissions for UNIXPATH? Only used if SERVE is unix.


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


How long is a validation challenge valid. After this time period, a fresh random challenge code will be generated and the retry limit counter (against guessing attacks) will be reset (to 3).


How long is a validation allowed to take (time from /setup to /token). After this time, the garbage collection process can delete all associated data. (Note that tokens will always allow access to 1h after they have been issued, regardless of when the validation expires).


Which command should we execute to transmit the challenge code to the address. The address is given as the first argument, while the message to send is provided on stdin. Templates (possibly without the necessary credentials) for such commands are provided as challenger-send-email.sh, challenger-send-post.sh and challenger-send-sms.sh.


Type of the address that is being collected, returned as part of the address_type in the /info endpoint. Examples include email or phone.


JSON object with a map of keys (names of the fields of the address to be entered by the user) to objects with a “regex” (string) containing an extended Posix regular expression for allowed address field values, and a “hint”/”hint_i18n” giving a human-readable explanation to display if the value entered by the user does not match the regex. Keys that are not mapped to such an object have no restriction on the value provided by the user. Examples would be ‘{“email”:{“hint”:”valid e-mail address required”,”regex”:”^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$”}’ or ‘{“zip”:{“hint”:”numeric zip code required”,”regex”:”^[0-9]+$”}’.

15.6.3. SEE ALSO

challenger-dbinit(1), challenger-httpd(1), challenger-config(1).

15.6.4. BUGS

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