Difference between revisions of "Job Module"
m (CG moved page Jobs Module to Job Module) |
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+ | {{Announce|Updated with Version 10:}} Renamed from ''Jobs Module'' to ''Job Module''. | ||
+ | |||
This [[Module Library|XQuery Module]] provides functions for organizing scheduled, queued, running and cached jobs. Jobs can be commands, queries, client or HTTP requests. | This [[Module Library|XQuery Module]] provides functions for organizing scheduled, queued, running and cached jobs. Jobs can be commands, queries, client or HTTP requests. | ||
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=Services= | =Services= | ||
− | A job can be registered as ''service'' by supplying the {{Code|service}} option to {{Function|Jobs| | + | A job can be registered as ''service'' by supplying the {{Code|service}} option to {{Function|Jobs|job:eval}}: |
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
(: register job as service; will be run every day at 1 am :) | (: register job as service; will be run every day at 1 am :) | ||
− | + | job:eval('db:drop("tmp")', (), map { 'id':'cleanup', 'start':'01:00:00', 'interval':'P1D', 'service': true() }), | |
(: list registered services :) | (: list registered services :) | ||
− | + | job:services(), | |
(: result: <job base-uri="..." id="cleanup" interval="P1D" start="01:00:00">db:drop("tmp")</job> :) | (: result: <job base-uri="..." id="cleanup" interval="P1D" start="01:00:00">db:drop("tmp")</job> :) | ||
(: unregister job :) | (: unregister job :) | ||
− | + | job:stop('cleanup', map { 'service': true() }) | |
</syntaxhighlight> | </syntaxhighlight> | ||
Line 31: | Line 33: | ||
There are cases in which a client does not, or cannot, wait until a request is fully processed. The client may be a browser, which sends an HTTP request to the server in order to start another time-consuming query job. The functions in this section allow you to register a new query job from a running query. Jobs can be executed immediately (i.e., as soon as the [[Transaction Management#Concurrency Control|Concurrency Control]] allows it) or scheduled for repeated execution. Each registered job gets a job id, and the id can be used to retrieve a query result, stop a job, or wait for its termination. | There are cases in which a client does not, or cannot, wait until a request is fully processed. The client may be a browser, which sends an HTTP request to the server in order to start another time-consuming query job. The functions in this section allow you to register a new query job from a running query. Jobs can be executed immediately (i.e., as soon as the [[Transaction Management#Concurrency Control|Concurrency Control]] allows it) or scheduled for repeated execution. Each registered job gets a job id, and the id can be used to retrieve a query result, stop a job, or wait for its termination. | ||
− | == | + | ==job:eval== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:eval|$query as xs:anyAtomicItem|xs:string}}<br />{{Func|job:eval|$query as xs:anyAtomicItem, $bindings as map(*)?|xs:string}}<br />{{Func|job:eval|$query as xs:anyAtomicItem, $bindings as map(*)?, $options as map(*)?|xs:string}}<br /> |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
|Schedules the evaluation of the supplied {{Code|$query}} ({{Code|xs:string}}, or of type {{Code|xs:anyURI}}, pointing to a resource), and returns a query id. The query will be queued, and the result will optionally be cached. Queries can be updating. Variables and the context value can be declared via {{Code|$bindings}} (see [[XQuery Module#xquery:eval|xquery:eval]] for more details). The following {{Code|$options}} can be supplied: | |Schedules the evaluation of the supplied {{Code|$query}} ({{Code|xs:string}}, or of type {{Code|xs:anyURI}}, pointing to a resource), and returns a query id. The query will be queued, and the result will optionally be cached. Queries can be updating. Variables and the context value can be declared via {{Code|$bindings}} (see [[XQuery Module#xquery:eval|xquery:eval]] for more details). The following {{Code|$options}} can be supplied: | ||
* {{Code|cache}}: indicates if the query result will be cached or ignored (default: <code>false</code>): | * {{Code|cache}}: indicates if the query result will be cached or ignored (default: <code>false</code>): | ||
− | ** The result will be cached in main-memory until it is fetched via [[# | + | ** The result will be cached in main-memory until it is fetched via [[#job:result|job:result]], or until {{Option|CACHETIMEOUT}} is exceeded. |
** If the query raises an error, it will be cached and returned instead. | ** If the query raises an error, it will be cached and returned instead. | ||
* {{Code|start}}: a dayTimeDuration, time, dateTime or integer can be specified to delay the execution of the query: | * {{Code|start}}: a dayTimeDuration, time, dateTime or integer can be specified to delay the execution of the query: | ||
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| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * Cache query result. The returned id can be used to pick up the result with [[# | + | * Cache query result. The returned id can be used to pick up the result with [[#job:result|job:result]]: |
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | + | job:eval("1+3", (), map { 'cache': true() }) | |
</syntaxhighlight> | </syntaxhighlight> | ||
* A happy birthday mail will be sent at the given date: | * A happy birthday mail will be sent at the given date: | ||
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | + | job:eval("import module namespace mail='mail'; mail:send('Happy birthday!')", | |
(), map { 'start': '2018-09-01T06:00:00' })}} | (), map { 'start': '2018-09-01T06:00:00' })}} | ||
</syntaxhighlight> | </syntaxhighlight> | ||
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<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
declare %rest:POST("{$query}") %rest:path('/start-scheduling') function local:start($query) { | declare %rest:POST("{$query}") %rest:path('/start-scheduling') function local:start($query) { | ||
− | + | job:eval($query, (), map { 'start': '02:00:00', 'interval': 'P1D' }) | |
}; | }; | ||
declare %rest:path('/stop-scheduling/{$id}') function local:stop($id) { | declare %rest:path('/stop-scheduling/{$id}') function local:stop($id) { | ||
− | + | job:stop($id) | |
}; | }; | ||
</syntaxhighlight> | </syntaxhighlight> | ||
* Query execution is scheduled for every second, and for 10 seconds in total. As the query itself will take 1.5 seconds, it will only be executed every second time: | * Query execution is scheduled for every second, and for 10 seconds in total. As the query itself will take 1.5 seconds, it will only be executed every second time: | ||
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | + | job:eval("prof:sleep(1500)", (), map { 'interval': 'PT1S', 'end': 'PT10S' }) | |
</syntaxhighlight> | </syntaxhighlight> | ||
* The query in the specified file will be evaluated once: | * The query in the specified file will be evaluated once: | ||
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | + | job:eval(xs:anyURI('cleanup.xq')) | |
</syntaxhighlight> | </syntaxhighlight> | ||
* The following expression, if stored in a file, will be evaluated every 5 seconds: | * The following expression, if stored in a file, will be evaluated every 5 seconds: | ||
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | + | job:eval( | |
static-base-uri(), | static-base-uri(), | ||
map { }, | map { }, | ||
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|} | |} | ||
− | == | + | ==job:result== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:result|$id as xs:string|item()*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
declare %rest:path('/result/{$id}') function local:result($id) { | declare %rest:path('/result/{$id}') function local:result($id) { | ||
− | + | job:result($id) | |
}; | }; | ||
</syntaxhighlight> | </syntaxhighlight> | ||
* The following query demonstrates how the results of an executed query can be returned within the same query (see below why you should avoid this pattern in practice): | * The following query demonstrates how the results of an executed query can be returned within the same query (see below why you should avoid this pattern in practice): | ||
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | let $query := | + | let $query := job:eval('(1 to 10000000)[. = 1]', map { }, map { 'cache': true() }) |
return ( | return ( | ||
− | + | job:wait($query), | |
− | + | job:result($query) | |
) | ) | ||
</syntaxhighlight> | </syntaxhighlight> | ||
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|} | |} | ||
− | == | + | ==job:stop== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:stop|$id as xs:string|empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
− | | <code> | + | | <code>job:list()[. != job:current()] ! job:stop(.)</code> stops and discards all jobs except for the current one. |
|} | |} | ||
− | == | + | ==job:wait== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:wait|$id as xs:string|empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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=Listing Jobs= | =Listing Jobs= | ||
− | == | + | ==job:current== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:current||xs:string}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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|} | |} | ||
− | == | + | ==job:list== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:list||xs:string*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
− | | <code> | + | | <code>job:list()</code> returns the same job id as {{Function|Jobs|job:current}} if no other job is registered. |
|} | |} | ||
− | == | + | ==job:list-details== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:list-details||element(job)*}}<br/>{{Func|job:list-details|$id as xs:string|element(job)*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
− | | <code> | + | | <code>job:list-details()</code> returns information on the currently running job and possibly others: |
<syntaxhighlight lang="xml"> | <syntaxhighlight lang="xml"> | ||
<job id="job1" type="XQuery" state="running" user="admin" duration="PT0.001S"> | <job id="job1" type="XQuery" state="running" user="admin" duration="PT0.001S"> | ||
− | XQUERY | + | XQUERY job:list-details() |
</job> | </job> | ||
</syntaxhighlight> | </syntaxhighlight> | ||
|} | |} | ||
− | == | + | ==job:bindings== |
{{Announce|Introduced with Version 10.0}} | {{Announce|Introduced with Version 10.0}} | ||
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|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:bindings|$id as xs:string|map(*)}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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|} | |} | ||
− | == | + | ==job:finished== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:finished|$id as xs:string|xs:boolean}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
Line 238: | Line 240: | ||
|} | |} | ||
− | == | + | ==job:services== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func| | + | |{{Func|job:services||element(job)*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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;Version 10.0 | ;Version 10.0 | ||
− | * Added: {{Function|Jobs| | + | * Updated: Renamed from ''Jobs Module'' to ''Job Module''. |
+ | * Added: {{Function|Jobs|job:bindings}} | ||
;Version 9.7 | ;Version 9.7 | ||
− | * Updated: {{Function|Jobs| | + | * Updated: {{Function|Jobs|job:result}}: return empty sequence if no result is cached. |
;Version 9.5 | ;Version 9.5 | ||
− | * Updated: {{Function|Jobs| | + | * Updated: {{Function|Jobs|job:eval}}: integers added as valid start and end times. |
;Version 9.4 | ;Version 9.4 | ||
− | * Updated: {{Function|Jobs| | + | * Updated: {{Function|Jobs|job:eval}}: option added for writing log entries. |
− | * Updated: {{Function|Jobs| | + | * Updated: {{Function|Jobs|job:list-details}}: interval added. |
;Version 9.2 | ;Version 9.2 | ||
− | * Deleted: | + | * Deleted: job:invoke (merged with {{Function|Jobs|job:eval}}) |
;Version 9.1 | ;Version 9.1 | ||
− | * Updated: {{Function|Jobs| | + | * Updated: {{Function|Jobs|job:list-details}}: registration time added. |
;Version 9.0 | ;Version 9.0 | ||
− | * Added: {{Function|Jobs| | + | * Added: {{Function|Jobs|job:invoke}}, [[#Services|Services]] |
;Version 8.6 | ;Version 8.6 | ||
− | * Updated: {{Function|Jobs| | + | * Updated: {{Function|Jobs|job:eval}}: <code>id</code> option added. |
The module was introduced with Version 8.5. | The module was introduced with Version 8.5. |
Revision as of 18:14, 18 July 2022
Updated with Version 10: Renamed from Jobs Module to Job Module.
This XQuery Module provides functions for organizing scheduled, queued, running and cached jobs. Jobs can be commands, queries, client or HTTP 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.
Services
A job can be registered as service by supplying the service
option to job:eval
:
<syntaxhighlight lang="xquery"> (: register job as service; will be run every day at 1 am :) job:eval('db:drop("tmp")', (), map { 'id':'cleanup', 'start':'01:00:00', 'interval':'P1D', 'service': true() }),
(: list registered services :) job:services(), (: result: <job base-uri="..." id="cleanup" interval="P1D" start="01:00:00">db:drop("tmp")</job> :)
(: unregister job :) job:stop('cleanup', map { 'service': true() }) </syntaxhighlight>
Some more notes:
- All job services will be scheduled for evaluation when the BaseX server or BaseX HTTP server is started.
- If a job service is outdated (e.g. because a supplied end time has been exceeded), it will be removed from the jobs file at startup time.
- The job definitions are stored in a
jobs.xml
file in the database directory. It can also be edited manually.
Executing Jobs
There are cases in which a client does not, or cannot, wait until a request is fully processed. The client may be a browser, which sends an HTTP request to the server in order to start another time-consuming query job. The functions in this section allow you to register a new query job from a running query. Jobs can be executed immediately (i.e., as soon as the Concurrency Control allows it) or scheduled for repeated execution. Each registered job gets a job id, and the id can be used to retrieve a query result, stop a job, or wait for its termination.
job:eval
Signatures | job:eval($query as xs:anyAtomicItem) as xs:string job:eval($query as xs:anyAtomicItem, $bindings as map(*)?) as xs:string job:eval($query as xs:anyAtomicItem, $bindings as map(*)?, $options as map(*)?) as xs:string |
Summary | Schedules the evaluation of the supplied $query (xs:string , or of type xs:anyURI , pointing to a resource), and returns a query id. The query will be queued, and the result will optionally be cached. Queries can be updating. Variables and the context value can be declared via $bindings (see xquery:eval for more details). The following $options can be supplied:
|
Errors | overflow : Query execution is rejected, because too many jobs are queued or being executed. CACHETIMEOUT can be decreased if the default setting is too restrictive.range : A specified time or duration is out of range.id : The specified id is invalid or has already been assigned.options : The specified options are conflicting.
|
Examples |
<syntaxhighlight lang="xquery"> job:eval("1+3", (), map { 'cache': true() }) </syntaxhighlight>
<syntaxhighlight lang="xquery"> job:eval("import module namespace mail='mail'; mail:send('Happy birthday!')", (), map { 'start': '2018-09-01T06:00:00' })}} </syntaxhighlight>
<syntaxhighlight lang="xquery"> declare %rest:POST("{$query}") %rest:path('/start-scheduling') function local:start($query) { job:eval($query, (), map { 'start': '02:00:00', 'interval': 'P1D' }) }; declare %rest:path('/stop-scheduling/{$id}') function local:stop($id) { job:stop($id) }; </syntaxhighlight>
<syntaxhighlight lang="xquery"> job:eval("prof:sleep(1500)", (), map { 'interval': 'PT1S', 'end': 'PT10S' }) </syntaxhighlight>
<syntaxhighlight lang="xquery"> job:eval(xs:anyURI('cleanup.xq')) </syntaxhighlight>
<syntaxhighlight lang="xquery"> job:eval( static-base-uri(), map { }, map { 'start': 'PT5S' } ) </syntaxhighlight> |
job:result
Signatures | job:result($id as xs:string) as item()*
|
Summary | Returns the cached result of a job with the specified job $id :
|
Examples |
<syntaxhighlight lang="xquery"> declare %rest:path('/result/{$id}') function local:result($id) { job:result($id) }; </syntaxhighlight>
<syntaxhighlight lang="xquery"> let $query := job:eval('(1 to 10000000)[. = 1]', map { }, map { 'cache': true() }) return ( job:wait($query), job:result($query) ) </syntaxhighlight> Queries of this kind can cause deadlocks! If the original query and the new query perform updates on the same database, the second query will only be run after the first one has been executed, and the first query will wait for the second query forever. You should resort to xquery:fork-join if you want to have full control on parallel query execution. |
job:stop
Signatures | job:stop($id as xs:string) as empty-sequence()
|
Summary | Triggers the cancelation of a job with the specified $id , drops the cached result of a query, or cancels a scheduled job. Unknown ids are ignored. All jobs are gracefully stopped; it is up to the process to decide when it is safe to shut down. The following $options can be supplied:
|
Examples | job:list()[. != job:current()] ! job:stop(.) stops and discards all jobs except for the current one.
|
job:wait
Signatures | job:wait($id as xs:string) as empty-sequence()
|
Summary | Waits for the completion of a job with the specified $id :
|
Errors | self : The current job is addressed. |
Listing Jobs
job:current
Signatures | job:current() as xs:string
|
Summary | Returns the id of the current job. |
job:list
Signatures | job:list() as xs:string*
|
Summary | Returns the ids of all jobs that are currently registered. The list includes scheduled, queued, running, stopped, and finished jobs with cached results. |
Examples | job:list() returns the same job id as job:current if no other job is registered.
|
job:list-details
Signatures | job:list-details() as element(job)* job:list-details($id as xs:string) as element(job)*
|
Summary | Returns information on all jobs that are currently registered, or on a job with the specified $id (or an empty sequence if this job is not found). The list includes scheduled, queued, running jobs, and cached jobs. A string representation of the job, or its URI, will be returned as value. The returned elements have additional attributes:
|
Examples | job:list-details() returns information on the currently running job and possibly others:
<syntaxhighlight lang="xml"> <job id="job1" type="XQuery" state="running" user="admin" duration="PT0.001S"> XQUERY job:list-details() </job> </syntaxhighlight> |
job:bindings
Introduced with Version 10.0
Signatures | job:bindings($id as xs:string) as map(*)
|
Summary | Returns the variable bindings of an existing job with the specified $id . If no variables have been bound to this job, an empty map is returned.
|
job:finished
Signatures | job:finished($id as xs:string) as xs:boolean
|
Summary | Indicates if the evaluation of an already running job with the specified $id has finished. As the ids of finished jobs will usually be discarded, unless caching is enabled, the function will also return true for unknown jobs.
|
job:services
Signatures | job:services() as element(job)*
|
Summary | Returns a list of all jobs that have been persistently registered as Services. |
Errors | services : Registered services cannot be parsed. |
Errors
Code | Description |
---|---|
options
|
The specified options are conflicting. |
id
|
The specified id is invalid or has already been assigned. |
overflow
|
Too many queries or query results are queued. |
range
|
A specified time or duration is out of range. |
running
|
A query is still running. |
self
|
The current job cannot be addressed. |
service
|
Registered services cannot be parsed, added or removed. |
Changelog
- Version 10.0
- Updated: Renamed from Jobs Module to Job Module.
- Added:
job:bindings
- Version 9.7
- Updated:
job:result
: return empty sequence if no result is cached.
- Version 9.5
- Updated:
job:eval
: integers added as valid start and end times.
- Version 9.4
- Updated:
job:eval
: option added for writing log entries. - Updated:
job:list-details
: interval added.
- Version 9.2
- Deleted: job:invoke (merged with
job:eval
)
- Version 9.1
- Updated:
job:list-details
: registration time added.
- Version 9.0
- Added:
job:invoke
, Services
- Version 8.6
- Updated:
job:eval
:id
option added.
The module was introduced with Version 8.5.