/etc/yaws.conf - Configuration file for the yaws webserver
DESCRIPTION
Yaws is fast lightweight webserver. It reads a configuration file called
yaws.conf to control its operations. The configuration contains two distinct
parts a global part which affects all the virtual hosts and a server part
where options for each virtual host is supplied.
GLOBAL PART
logdir = Directory
All yaws logs will be written to files in this directory. There are several
different log files written by yaws.
report.log - this is a text file that contains all error logger
printouts from yaws.
Host.access - for each virtual host served by yaws, a file Host.access
will be written which contains an access log in Common Log Format.
trace.http - this file contains the HTTP trace if that is enabled
auth.log - If configured, all http auth related messages
goes here.
trace.traffic - this file contains the traffic trace if that is enabled
The default value for logdir is "."
ebin_dir = Directory
This directive adds Directory to the erlang search path. It is possible to
have several of these command in the configuration file.
id = String
It is possible run multiple yaws servers on the same machine. We use the
id of a yaws server to control it using the different ctl commands such
as:
# /usr/local/bin/yaws -I foobar -s
To stop the Yaws server with id "foobar". Only the user that started
the server called foobar is allowd to stop and control it. This is achieved
through file permissions on the control file which will reside in
"/tmp/yaws/foobar/ctl"
There can never be two yaws servers on the same machine with identical ids.
include_dir = Directory
This directive adds Directory to the path of directories where the erlang
compiler seraches for include files. We need to use this if we want to
include .hrl files in our yaws erlang code.
max_num_cached_files = Integer
Yaws will cache small files such as commonly accessed GIF images in RAM.
This directive sets a maximum number on the number of cached files.
The default value is 400.
max_num_cached_bytes = Integer
This directive controls the total amount of RAM which can maximally be
used for cached RAM files. The default value is 1000000, 1 megabyte.
max_size_cached_file = Integer
This directive sets a maximum size on the files that are RAM cached by yaws.
The default value i 8000, 8 kBytes.
cache_refresh_secs = Integer
The RAM cache is used to serve pages that sit in the cache. An entry sits in
cache at most cache_refresh_secs number of seconds. The default is 30. This means that when the content is updated under the docroot, that change doesn't show
until 30 seconds have passed. While developing a yaws site,
it may be convenient to set this value to 0. If the debug flag (-d) is apssed
to the yaws start script, this value is automatically set to 0.
trace = traffic | http
This enables traffic or http tracing. Tracing is also possible to enable with
a command line flag to yaws.
auth_log = true | false
Enable or disable the auth log. Default is true.
B log_wrap_size = Integer
The logs written by yaws are all wrap logs, the default value at the
size where they wrap around and the original gets renamed to File.old
is 1000000, 1 M. This value can changed.
B log_resolve_hostname = Bool
By default the client host IP is not resolved in the access logs.
B fail_on_bind_err = Bool
Fail completely or not if yaws fails to bind a listen socket
Default is true.
copy_error_log = true | false
Enable or disable copying of the error log. When we run in
embedded mode, that may very well be some other systems process
that is responsible for writing the errorlog to a file whereas
when we run in normal standalone mode, we typicall ywant the
erlang errorlog written to a report.log file.
Default value is true.
backwards_compat_parse = true | false
Versions of Yaws > than 1.41 changes the return value
of the parse_query and parse_post functions. Earlier versions
used {Key, Val} where Key was an atom. This made Yaws vulnerable
for DOS attacks. Set this flag to keep the old deeprecated
and vulnerable behaviour. I versions > that 1.41 the Key is a list/string.
username = Username
When running a Yaws server in production, it may feel safe
to run yaws as a different user than root. Set this value to a
non priviliged username on the system, such as "nobody".
Yaws will initially have to run a root in order to properly
listen to priviliged ports .
SERVER PART
Yaws can virthost several webservers on the same ip address as well
as several webservers on different ip addresses. The on limitation here is
that there can be only one server with ssl enabled per each individual ip address.
Each virttual host is defined within a matching pair of <server ServerName>
and </server>. The ServerName will be the name of the webserver.
The following directives are allowed inside a server definition.
port = Port
This makes the server listen on Port
listen = IpAddress
This makes the server listen on IpAddress
When virthosting several servers on the same ip/port address, if the
browser doesn't send a Host: field, yaws will pick the first
server specified in the config file.
If the specified ip address is 0.0.0.0 yaws will listen on all local ip
addresses on the specified port.
rhost = Host[:Port]
This forces all local redirects issued by the server to go to Host.
This is useful when yaws listens to a port which is different from
the port that the user connects to. For example, running yaws as a
non-privileged user makes it impossible to listen to port 80, since
that port can only be opened by a privileged user. Instead yaws
listens to a high port number port, 8000, and iptables are used to
redirect traffic to port 80 to port 8000 (most NAT:ing firewalls
will also do this for you).
rscheme = http | https
This forces all local redirects issued by the server to use this
method. This is useful when an SSL off-loader, or stunnel, is used in
front of yaws.
access_log = true | false
Setting this directive to false turns of traffic logging for this
virtual server. The default value is true.
dir_listings = true | true_nozip | false
Setting this directive to false disallows the automatic
dir listing feature of Yaws. A status code 403 Forbidden will be sent.
Set to true_nozip to avoid the auto-generated all.zip entries.
docroot = Directory
This makes the server serve all its content from Directory
partial_post_size = Integer
When a yaws file receives large POSTs, the amount of data received
in each chunk is determined by the this parameter.
The deafult value is 10240.
tilde_expand = true|false
If this value is set to false yaws will never
do tilde expansion. The default is false. tilde_expansion is the
mechanism whereby a URL ob the form http://www.foo.com/~username
is changed into a request where the docroot for that
particular request is set to the directory ~username/public_html/
The default value is false.
allowed_scripts = [ListOfSuffixes]
The allowed script types for this server. Recognized are `yaws',
`cgi', `php'. Default is allowed_scripts = yaws.
php_exe_path = Path
The name of (and possibly path to) the php executable used to
interpret php scripts (if allowed). Default is
php_exe_path = php.
appmods = [ListOfModuleNames]
If any the names in ListOfModuleNames appear as components in the
path for a request, the path request parsing will terminate and
that module will be called. There is also an alternate syntax for
specifying the appmods if we don't want our internal erlang module
names to be exposed in the URL paths.
We can specify
appmods = <Path1, Module1> <Path2, Modules2> ...
Assume for example that we have
the URL http://www.hyber.org/myapp/foo/bar/baz?user=joe
while we have the module foo defined as an appmod, the
function foo:out(Arg) will be invoked
instead of searching the filesystems below the point foo.
The Arg argument will have the missing path part supplied in its
appmoddata field.
errormod_404 = Module
It is possible to set a special module that handles
404 Not Found messages.
The function Module:out404(Arg, GC, SC) will
be invoked. The arguments are
Arg is a #arg{} record
GC is a #gconf{} record (defined in yaws.hrl)
SC is a #sconf{} record (defined in yaws.hrl)
The function can and must do the same things that
a normal out/1 does.
errormod_crash = Module
It is possible to set a special module that handles
the HTML generation of server crash messages. The default
is to display the entire formated crash message in the
browser. This is good for debugging but not in production.
The function Module:crashmsg(Arg, SC, Str) will be
called. The Str is the real crash message formated as a string.
arg_rewrite_mod = Module
It is possible to install a module that rewrites all the
Arg #arg{} records at an early stage in the yaws server.
This can be used to do various things such as checking a cookie,
rewriting paths etc.
start_mod = Module
Defines a user provided callback module.
At startup of the server, Module:start/1 will be called.
The #sconf{} record (defined in yaws.hrl) will be used
as the input argument. This makes it possible for a user
application to syncronize the startup with the yaws server
as well as getting hold of user specific configuration data,
see the explanation for the <opaque> context.
revproxy = Prefix Url
Make yaws a reverse proxy. The Prefix is a path inside our own docroot
and the Url argument is an rli pointing to a website we want to "mount"
under the path which is Prefix.
Example: revproxy = /tmp/foo http://yaws.hyber.org
Makes the hyber website appear under /tmp/foo
It is possible to have multiple reverse proxies inside the same server.
<ssl> .... </ssl>
This begins and ends an SSL configuration for this server.
keyfile = File
Specifies which file contains the private key for the certificate.
certfile = File
Specifies which file contains the certificate for the server.
cacertfile = File
File If the server is setup to require client certificates. This file needs to contain all the certificates of the acceptable signers for the client certs.
verify = 1 | 2 | 3
Specifies the level of verification the server does on clinet certs. 1 means nothing, 2 means the the server will ask the client for a cert but not fail if the client doesn't supply a client cert, 3 means that the server requires the client to supply a client cert.
depth = Int
Specifies the depth of certificate chains the server is prepared to follow when verifying client certs.
password = String
String If the private key is encrypted on disc, this password is the 3des key to decrypt it.
ciphers = String
* This string specifies the ssl cipher string. The syntax of the ssl cipher string is a little horrible sublanguage of its own. It is documented in the ssl man page for "ciphers".
</ssl>
Ends an SSL definition
<auth> ... </auth>
Defines an auth structure. The following items are allowed
within a matching pair of <auth> and </auth> delimiters.
dir = Dir
Makes Dir to be controlled bu WWW-authenticate headers. In order for
a user to have access to WWW-Authenticate controled directory, the user
must supply a password. The Dir must be specified relative to the docroot.
realm = Realm
In the directory defined here, the WWW-Authenticate Realm is set to
this value.
user = User:Password
Inside this directory, the user User has access if the user supplies
the password Password in the popup dialogue presented by the browser.
We can obviously have several of these value inside a single <auth> </auth>
pair.
The usage of User:Password in the actual config file is deprecated
as of release 1.51. It is prefered to have the users in a file called
.yaws_auth in the actual directory. The .yaws_auth file has to be
file parseable by file:consult/1
Each row of the file must contain terms on the form
{User, Password}.
Where both User and Password should be strings.
The .yaws_auth file mechanism is not (yet) recursive. Thus
any subdirectories to Dir are not automatically also protected.
The .yaws_auth file is never visible in a dir listing
</auth>
Ends an auth definition
<opaque> .... </opaque>
This begins and ends an opaque configuration context for this server,
where 'Key = Value' directives can be specified. These directives is
ignored by yaws (hence the name opaque), but can be accessed as a list
of tuples {Key,Value} stored in the #sconf.opaque record entry. See also
the description of the start_mod directive.
keyfile = File
EXAMPLES
The following example defines a single server on port 80.
An example with www-authenticate and no access logging at all.
logdir = /var/log/yaws
<server www.mydomain.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www
access_log = false
<auth>
dir = secret/dir1
realm = foobar
user = jonny:verysecretpwd
user = benny:thequestion
user = ronny:havinganamethatendswithy
</auth>
</server>
An example specifying a user defined module to be called
at startup, as well as some user specific configuration.
<server www.funky.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www_funky_org
start_mod = btt
<opaque>
mydbdir = /tmp
mylogdir = /tmp/log
</opaque>
</server>
And finally a sligthly more complex example
with two servers on the same ip, and one ssl server on a
different ip.
When there are more than one server on the same IP, and they have different
names the server must be able to choose one of them if the client
doesn't send a Host: header. yaws will choose the first one defined in the
conf file.
