uriworkermap.properties configuration

+ + &project; + + + Rainer Jung + Mladen Turk + uriworkermap.properties configuration + + + + +

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+The forwarding of requests from the web server to tomcat gets configured by defining mapping rules. +Such a rule maps requests to workers. The request part of the map is described by a URI pattern, +the worker by it's worker name. +

+The so-called uriworkermap file is a mechanism of defining rules, +which works for all web servers. There exist also other web server specific configuration +options for defining rules, which will be mostly discussed on the reference pages for +configuring tomcat connectors for the individual web servers. +

+The name of the file is usually uriworkermap.properties, +although this is configurable in the web server. +Please consult the web server specific documentation pages on +how to enable the uriworkermap file. +

+The main features supported by the uriworkermap file are +

+Support for comments in the rule file. +
+Exact and wildchar matches, shortcuts to map a directory and all including content. +
+Exclusion rules, disabling of rules and rule priorities. +
+Rule extensions, modifying worker behaviour per rule. +
+Virtual host integration: uri mapping rules can be expressed per virtual host. +The details are web server specific though. +
+Dynamic reloading: The file gets checked periodically for changes. +New versions are automatically reloaded without web server restarts. +
+Integration with the status worker. +

+The following sections describe these aspects in more detail. +

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+The file has a line based format. There are no continuation characters, +so each rule needs to be defined on a single line. Each rule is a pair consisting +of a URI pattern and a worker name, combined by an equals sign '=': + + /myapp=myworker + +The URI pattern is case sensitive. +

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+All text after and including the character '#' gets ignored and can be used for comments. +Leading and trailing white space gets trimmed around the URI pattern and also around the worker name. +The following definitions are all equivalent: + + # This is a white space example + /myapp=myworker + /myapp=myworker + /myapp = myworker + +

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+Inside the URI pattern three special characters can be used, '*', '?' and '|'. +The character '*' is a wildchar that matches any number of arbitrary characters +in the URI, '?' matches exactly one character. +Each URI pattern has to start with the character '/', or with '*' or with '?', +optionally prefixed by any combination of the modifiers '!' and '-' (see next section). + + # Mapping the URI /myapp1 and everything under /myapp1/: + /myapp1=myworker-a + /myapp1/*=myworker-a + # Mapping all URI which end with a common suffix: + *.jsp=myworker + *.do=myworker + +Since the first case of mapping a certain location and everything inside +it is very common, the character '|' gives a handy shortcut: + + # Mapping the URI /myapp1 and everything under /myapp1/: + /myapp1|/*=myworker-a + +The pattern 'X|Y' is exactly equivalent to the two maps 'X' and 'XY'. +

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+Exclusion rules allows to define exclusions from URI rules, which would forward +requests to tomcat. If the exclusion rule matches, the request will not be forwarded. +This is usually used to serve static content by the web server. +A rule is an exclusion rule, if it is suffixed with '!': + + # Mapping the URI /myapp and everything under /myapp/: + /myapp|/*=myworker + # Exclude the subdirectory static: + !/myapp/static|/*=myworker + # Exclude some suffixes: + !*.html=myworker + +An exclusion rule overrides a normal mapping rule only, if the worker names in the +normal rule and in the exclusion rule are the same. Starting with version 1.2.26 of JK +you can apply an exclusion rule to any worker, by using the star character '*' as +the worker name in the exclusion rule. +More complex patterns in exclusion worker names are not allowed. + + # Mapping the webapps /myapp1 and /myapp2: + /myapp1|/*=myworker1 + /myapp2|/*=myworker2 + # Exclude the all subdirectories static for all workers: + !/*/static|/*=* + # Exclude some suffixes for all workers: + !*.html=* + +

+Rule disabling comes into play, if your web server merges rules from various sources, +and you want to disable any rule defined previously. Since the uriworkermap file gets +reloaded dynamically, you can use this to temporarily disable request forwarding: +A rule gets disabled, if it is suffixed with '-': + + # We are not in maintenance. + # The maintenance rule got defined somewhere else. + -/*=maintenance + +Exclusion rules can get disabled as well, then the rule starts with '-!'. +

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+The most restrictive URI pattern is applied first. More precisely the URI patterns are +sorted by the number of '/' characters in the pattern (highest number first), and +rules with equal numbers are sorted by their string length (longest first). +

+If both distinctions still do not suffice, then the defining source of the rule is considered. +Rules defined in uriworkermap.properties come first, before rules defined by JkMount (Apache) +and inside workers.properties using the mount attribute. +

+All disabled rules are ignored. Exclusion rules are applied after all normal rules +have been applied. +

+There is no defined behaviour, for the following configuration conflict: +using literally the same URI pattern in the same defining source but with +different worker targets. +

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+Rule extensions were added in version 1.2.27 and are not available in earlier versions. +

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+Rule extensions are additional attributes, that can be attached to any rule. +They are added at the end of the rule, each extension separated by a semicolon: + + # This is an extension example, + # setting a reply_timeout of 1 minute + # only for this mapping. + /myapp=myworker;reply_timeout=60000 + # + # This is an example using multiple extensions + /myapp=myloadbalancer;reply_timeout=60000;stopped=member1 + +Attributes set via rule extensions always overwrite conflicting +configurations in the worker definition file. +

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+The extension reply_timeout sets a reply timeout for a single mapping rule. + + # Setting a reply_timeout of 1 minute + # only for this mapping. + /myapp=myworker;reply_timeout=60000 + +It overrides any reply_timeout defined for the worker. The extension allows +to set a reasonable default reply timeout to the worker, and a more relaxed +reply timeout to URLs, which are known to start time intensive tasks. +For a general description of reply timeouts see the +timeouts documentation. +

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+The extensions active, disabled, and stopped +can be used in a load balancer mapping rule to set selected members +of the load balancer into a special activation state. + + # Stop forwarding only for member1 of loadbalancer + /myapp=myloadbalancer;stopped=member1 + +Multiple members must be separated by commas or white space: + + # Stop forwarding for member01 and member02 of loadbalancer + # Disable forwarding for member21 and member22 of loadbalancer + /myapp=myloadbalancer;stopped=member01,member02;disabled=member21,member22 + +For the precise meaning of the activation states see the description of +activation. +

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+The extension fail_on_status can be used in any rule: + + # Send 503 instead of 404 and 500, + # and if we get a 503 also set the worker to error + /myapp=myworker;fail_on_status=-404,-500,503 + +Multiple status codes must be separated by commas. +For the precise meaning of the attribute see the description of +fail_on_status. +

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+The extension use_server_errors allows to let the web server +send an error page, instead of the backend (e.g. Tomcat) error page. +This is useful, if one wants to send customized error pages, but those are +not part of all web applications. They can then be put onto the web server. +

+The value of use_server_errors is a positive number. +Any request send to the backend, that returns with an http status +code bigger or equal to use_server_errors, will +be answered to the client with the error page of the web server +for this status code. + + # Use web server error page for all errors + /myapp=myworker;use_server_errors=400 + # Use web server error page only for technical errors + /myotherapp=myworker;use_server_errors=500 + +

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+When using IIS you can restrict individual rules to special virtual hosts +by prefixing the URI pattern with the virtual host information. +The rules is that the url must be prefixed with the host name. + + # Use www.foo.org as virtual host + /www.foo.org/myapp/*=myworker + # Use www.bar.org as virtual host + /www.bar.org/myapp/*=myworker + # Normal mapping + /mysecondapp/*=myworker + +

+Note that /mysecondapp/* will be mapped to all virtual hosts present. +In case one needs to prevent the mappings to some particular virtual host then +the exclusion rule must be used + + # Make sure the myapp is accessible by all virtual hosts + /myapp/*=myworker + # Disable mapping myapp for www.foo.org virtual host + !/www.foo.org/myapp/*=myworker + +

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+For Apache you can define individual uriworkermap files per virtual host. +The directive JkMountFile can be used in the main server and in each virtual host. +If a virtual host does not use JkMountfile, but JkMountCopy is set to 'On', +then it inherits the JkMountFile from the main server. If you want all vhost to inherit +mounts from the main server, you can set JkMountCopy to 'All' in the main server. +

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+When a request is being processed, tomcat connectors check the file modification time +of the uriworkermap file. To keep the performance penalty low, this happens only, +if the last check happened at least n seconds ago. +

+For Apache you can configure the interval "n" using the directive JkMountFileReload, +for IIS you would use the attribute worker_mount_reload. +The default value is 60 seconds. A value of "0" turns off the reloading. +

+If the file changed, it gets reloaded completely. If there exist rules coming +from other sources than the uriworkermap file (e.g. the workers.properties mount +attribute or JkMount with Apache httpd), the new uriworkermap file gets dynamically +merged with these ones exactly like when you do a web server restart. +

+Until version 1.2.19 reloading behaved slightly differently: it continuously added +the full contents of the uriworkermap file to the rule mapping. The merging rules +were, that duplicated got eliminated and old rules could be disabled, by defining the +rule as disabled in the new file. Rules never got deleted. +

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+The configuration view of the status worker also shows the various mapping rules. +After each worker's configuration, the rules are listed, that forward to this worker. +The list contains four columns: +

+the name of the virtual server +
+the URI pattern, prefixed with '-' for a disabled pattern and '!' for an exclusion pattern +
+the type of the rule: Exact or Wildchar +
+and the source of the rule definition: 'worker definition' for the workers.properties file (mount attribute), +'JkMount' for Apache httpd JkMount and it's relatives and finally 'uriworkermap' for the uriworkermap file. +

+Note: The following restriction has been removed starting with version 1.2.26. +
+For Apache httpd, there is an important subtlety: the request going to the status worker +gets executed in the context of some server (main or virtual). The status worker will only show the +mapping rules, that are defined for this server (main or virtual). +
+Until version 1.2.25 the list contained three columns: +

+the type of the rule: Exact or Wildchar, eventually prefixed with Disabled or Unmount (for exclusion rules) +
+the URI pattern +
+and the source of the rule definition: 'worker definition' for the workers.properties file (mount attribute), +'JkMount' for Apache httpd JkMount and it's relatives and finally 'uriworkermap' for the uriworkermap file. +

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