Difference between revisions of "Job Module"
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|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Schedules the execution of the supplied {{Code|$query}} and returns a query id. The query will be queued, and the result will optionally be cached. Queries may be updating. Variables and context items can be declared via {{Code|$bindings}} (see [[XQuery Module#xquery:eval|xquery:eval]] for more details). The {{Code|$options}} parameter contains | + | |Schedules the execution of the supplied {{Code|$query}} and returns a query id. The query will be queued, and the result will optionally be cached. Queries may be updating. Variables and context items can be declared via {{Code|$bindings}} (see [[XQuery Module#xquery:eval|xquery:eval]] for more details). The {{Code|$options}} parameter contains scheduling options: |
* {{Code|cache}}: indicates if the query result will be cached or ignored (default: <code>false</code>): | * {{Code|cache}}: indicates if the query result will be cached or ignored (default: <code>false</code>): | ||
** The result will be cached in main-memory until it is fetched via [[#jobs:result|jobs:result]], or until {{Option|CACHETIMEOUT}} is exceeded. | ** The result will be cached in main-memory until it is fetched via [[#jobs:result|jobs:result]], or until {{Option|CACHETIMEOUT}} is exceeded. | ||
− | ** If the query raises an error, it will be cached instead | + | ** If the query raises an error, it will be cached and returned instead. |
− | |||
* {{Code|start}}: a dayTimeDuration, time or dateTime can be specified to delay the execution of the query: | * {{Code|start}}: a dayTimeDuration, time or dateTime can be specified to delay the execution of the query: | ||
** If a dayTimeDuration is specified, the query will be queued after the specified duration has passed. Examples for valid values are: <code>P1D</code> (1 day), <code>PT5M</code> (5 minutes), <code>PT0.1S</code> (100 ms). An error will be raised if a negative value is specified. | ** If a dayTimeDuration is specified, the query will be queued after the specified duration has passed. Examples for valid values are: <code>P1D</code> (1 day), <code>PT5M</code> (5 minutes), <code>PT0.1S</code> (100 ms). An error will be raised if a negative value is specified. | ||
− | ** If a time is specified, the query will be | + | ** If a time is specified, the query will be executed at this time of the day. Examples for valid times are: <code>02:00:00</code> (2am), <code>12:00:00</code> (noon). If the time lies in the past, the query will be executed next day. |
− | ** If a dateTime is specified, the query will be | + | ** If a dateTime is specified, the query will be executed at this date. Examples for valid values are: <code>2018-12-31T23:59:59</code> (New Year's Eve 2018, close to midnight). An error will be raised if the specified time lies in the past. |
* {{Code|interval}}: a dayTimeDuration string can be specified to execute the query periodically. An error is raised if the specified interval is less than one second (<code>PT1S</code>). If the next scheduled call is due, and if a query with the same id is still running, it will be skipped. | * {{Code|interval}}: a dayTimeDuration string can be specified to execute the query periodically. An error is raised if the specified interval is less than one second (<code>PT1S</code>). If the next scheduled call is due, and if a query with the same id is still running, it will be skipped. | ||
− | * {{Code|base-uri}}: set [https://www.w3.org/TR/xquery-31/#dt-static-base-uri base-uri property] for the query. This URI will be used when resolving relative URIs | + | * {{Code|base-uri}}: set the [https://www.w3.org/TR/xquery-31/#dt-static-base-uri base-uri property] for the query. This URI will be used when resolving relative URIs, such as with {{Code|fn:doc}}. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
− | |{{Error|overflow|#Errors}} | + | |{{Error|overflow|#Errors}} Query execution is rejected, because too many jobs are queued or being executed. {{Option|CACHETIMEOUT}} can be decreased if the default setting is too restrictive.<br/>{{Error|range|#Errors}} A specified time or duration is out of range. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * | + | * Cache query result. An id will be returned, which can be used to pick up the result via [[#jobs:result|jobs:result]]): |
− | |||
<pre class='brush:xquery'> | <pre class='brush:xquery'> | ||
− | + | jobs:schedule("1+3", (), map { 'cache': true() }) | |
− | |||
− | |||
</pre> | </pre> | ||
− | * A | + | * A happy birthday mail will be sent at the given date: |
<pre class="brush:xquery"> | <pre class="brush:xquery"> | ||
− | jobs:schedule("import module namespace | + | jobs:schedule("import module namespace mail='mail'; mail:send('Happy birthday!')", |
− | (), map { 'start': ' | + | (), map { 'start': '2018-09-01T06:00:00', 'interval': 'P1D' })}} |
</pre> | </pre> | ||
* Query execution is scheduled for every second. As the query itself will take 1.5 seconds, it will only be executed every second time: | * Query execution is scheduled for every second. As the query itself will take 1.5 seconds, it will only be executed every second time: | ||
<pre class="brush:xquery"> | <pre class="brush:xquery"> | ||
jobs:schedule("prof:sleep(1500)", (), map { 'interval': 'PT1S' }) | jobs:schedule("prof:sleep(1500)", (), map { 'interval': 'PT1S' }) | ||
+ | </pre> | ||
+ | * The following [[RESTXQ]] functions can be called to execute a specified query at 2am every day. An id will be returned, which can be used to stop the scheduler again: | ||
+ | <pre class='brush:xquery'> | ||
+ | declare %rest:POST("{$query}") %rest:path('/start-scheduling') function local:start($query) { | ||
+ | jobs:schedule($query, (), map { 'start': '02:00:00', 'interval': 'P1D' }) | ||
+ | }; | ||
+ | declare %rest:path('/stop-scheduling/{$id}') function local:stop($id) { | ||
+ | jobs:stop($id) | ||
+ | }; | ||
</pre> | </pre> | ||
|} | |} |
Revision as of 11:50, 3 July 2016
This XQuery Module provides functions for organizing queued and running jobs (commands, queries, REST, RESTXQ and WebDAV requests).
Contents
Conventions
All functions in this module are assigned to the http://basex.org/modules/jobs
namespace, which is statically bound to the jobs
prefix. Errors will be bound to the same prefix.
Functions
jobs:current
Signatures | jobs:current() as xs:string
|
Summary | Returns the id of the current job. |
jobs:list
Signatures | jobs:list() as xs:string*
|
Summary | Returns the ids of all jobs that are currently queued or executed. |
Examples |
|
jobs:list-details
Signatures | jobs:list-details() as element(job)* jobs:list-details($id as xs:string) as element(job)*
|
Summary | Returns information on all jobs that are currently queued or executed. The input comprises the job id, the type (XQuery, a command, REST, RESTXQ), the time a job is already being evaluated, the state (queued, running, stopped, timeout, memory) and the user who started the job. |
Examples |
<job id="job1" type="XQuery" duration="PT0S" state="running" user="admin"> XQUERY jobs:list-details() </job> |
jobs:finished
Signatures | jobs:finished($id as xs:string) as xs:boolean
|
Summary | Indicates if the evaluation of a job with the specified $id has finished:
|
jobs:stop
Signatures | jobs:stop($id as xs:string) as empty-sequence()
|
Summary | Cancels the execution of a job with the specified $id , or drops the cached result of a query. Unknown ids are ignored. All jobs are gracefully stopped; it is up to the process to decide when it is safe to shut down.
|
Asynchronous Execution
Asynchronous query execution is recommendable if a client does not, or cannot, wait until a request is fully processed. This is e. g. the case with web browsers, which will usually cancel a request after a specific timeout. In such cases, you can use asynchronous execution to trigger another server-side process, which will start the time-consuming process, and fetch the result later on as soon as it is available.
jobs:schedule
Signatures | jobs:schedule($query as xs:string) as xs:string jobs:schedule($query as xs:string, $bindings as map(*)?) as xs:string jobs:schedule($query as xs:string, $bindings as map(*)?, $options as map(xs:string, xs:string)) as xs:string |
Summary | Schedules the execution of the supplied $query and returns a query id. The query will be queued, and the result will optionally be cached. Queries may be updating. Variables and context items can be declared via $bindings (see xquery:eval for more details). The $options parameter contains scheduling options:
|
Errors | overflow : Query execution is rejected, because too many jobs are queued or being executed. CACHETIMEOUT can be decreased if the default setting is too restrictive.range : A specified time or duration is out of range.
|
Examples |
jobs:schedule("1+3", (), map { 'cache': true() })
jobs:schedule("import module namespace mail='mail'; mail:send('Happy birthday!')", (), map { 'start': '2018-09-01T06:00:00', 'interval': 'P1D' })}}
jobs:schedule("prof:sleep(1500)", (), map { 'interval': 'PT1S' })
declare %rest:POST("{$query}") %rest:path('/start-scheduling') function local:start($query) { jobs:schedule($query, (), map { 'start': '02:00:00', 'interval': 'P1D' }) }; declare %rest:path('/stop-scheduling/{$id}') function local:stop($id) { jobs:stop($id) }; |
jobs:result
Signatures | jobs:result($id as xs:string) as item()*
|
Summary | Returns the cached result of a query with the specified job $id :
|
Errors | running : the job is still running.unknown : the supplied id is unknown: The id is unknown, or the result has already been retrieved. |
Examples |
declare %rest:path('/result/{$id}') function local:result($id) { jobs:result($id) };
let $query := jobs:schedule('(1 to 10000000)[. = 1]', map{}, map{ 'cache': true() }) return ( hof:until( function($f) { jobs:finished($query) }, function($f) { prof:sleep(10) }, () ), jobs:result($query) ) |
jobs:results
Signatures | jobs:results() as xs:string*
|
Summary | Returns the ids of all jobs for which results are cached. |
Errors
range
Code | Description |
---|---|
unknown
|
The supplied query id is unknown or not available anymore. |
running
|
A query is still running. |
overflow
|
Too many queries or query results are queued. |
A specified time or duration is out of range. |
Changelog
The module was introduced with Version 8.5.