OpenSearch/docs/painless/painless-contexts/painless-ingest-processor-context.asciidoc
Jack Conradson 293c8a2b24
Painless: Add an Ingest Script Processor Example (#32302)
This commit adds two pieces. The first is a small set of documentation providing 
instructions on how to get setup to run context examples. This will require a download 
similar to how Kibana works for some of the examples. The second is an ingest processor 
example using the downloaded data. More examples will follow as ideally one per PR. 
This also adds a set of tests to individually test each script as a unit test.
2018-08-09 14:24:55 -07:00

195 lines
8.0 KiB
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[[painless-ingest-processor-context]]
=== Ingest processor context
Use a Painless script in an {ref}/script-processor.html[ingest processor]
to modify documents upon insertion.
*Variables*
`params` (`Map`, read-only)::
User-defined parameters passed in as part of the query.
{ref}/mapping-index-field.html[`ctx['_index']`] (`String`)::
The name of the index.
{ref}/mapping-type-field.html[`ctx['_type']`] (`String`)::
The type of document within an index.
`ctx` (`Map`)::
Contains extracted JSON in a `Map` and `List` structure for the fields
that are part of the document.
*Side Effects*
{ref}/mapping-index-field.html[`ctx['_index']`]::
Modify this to change the destination index for the current document.
{ref}/mapping-type-field.html[`ctx['_type']`]::
Modify this to change the type for the current document.
`ctx` (`Map`)::
Modify the values in the `Map/List` structure to add, modify, or delete
the fields of a document.
*Return*
void::
No expected return value.
*API*
The standard <<painless-api-reference, Painless API>> is available.
*Example*
To run this example, first follow the steps in
<<painless-context-examples, context examples>>.
The seat data contains:
* A date in the format `YYYY-MM-DD` where the second digit of both month and day
is optional.
* A time in the format HH:MM* where the second digit of both hours and minutes
is optional. The star (*) represents either the `String` `AM` or `PM`.
The following ingest script processes the date and time `Strings` and stores the
result in a `datetime` field.
[source,Painless]
----
String[] split(String s, char d) { <1>
int count = 0;
for (char c : s.toCharArray()) { <2>
if (c == d) {
++count;
}
}
if (count == 0) {
return new String[] {s}; <3>
}
String[] r = new String[count + 1]; <4>
int i0 = 0, i1 = 0;
count = 0;
for (char c : s.toCharArray()) { <5>
if (c == d) {
r[count++] = s.substring(i0, i1);
i0 = i1 + 1;
}
++i1;
}
r[count] = s.substring(i0, i1); <6>
return r;
}
String[] dateSplit = split(ctx.date, (char)"-"); <7>
String year = dateSplit[0].trim();
String month = dateSplit[1].trim();
if (month.length() == 1) { <8>
month = "0" + month;
}
String day = dateSplit[2].trim();
if (day.length() == 1) { <9>
day = "0" + day;
}
boolean pm = ctx.time.substring(ctx.time.length() - 2).equals("PM"); <10>
String[] timeSplit = split(
ctx.time.substring(0, ctx.time.length() - 2), (char)":"); <11>
int hours = Integer.parseInt(timeSplit[0].trim());
int minutes = Integer.parseInt(timeSplit[1].trim());
if (pm) { <12>
hours += 12;
}
String dts = year + "-" + month + "-" + day + "T" +
(hours < 10 ? "0" + hours : "" + hours) + ":" +
(minutes < 10 ? "0" + minutes : "" + minutes) +
":00+08:00"; <13>
ZonedDateTime dt = ZonedDateTime.parse(
dts, DateTimeFormatter.ISO_OFFSET_DATE_TIME); <14>
ctx.datetime = dt.getLong(ChronoField.INSTANT_SECONDS)*1000L; <15>
----
<1> Creates a `split` <<painless-functions, function>> to split a
<<string-type, `String`>> type value using a <<primitive-types, `char`>>
type value as the delimiter. This is useful for handling the necessity of
pulling out the individual pieces of the date and time `Strings` from the
original seat data.
<2> The first pass through each `char` in the `String` collects how many new
`Strings` the original is split into.
<3> Returns the original `String` if there are no instances of the delimiting
`char`.
<4> Creates an <<array-type, array type>> value to collect the split `Strings`
into based on the number of `char` delimiters found in the first pass.
<5> The second pass through each `char` in the `String` collects each split
substring into an array type value of `Strings`.
<6> Collects the last substring into the array type value of `Strings`.
<7> Uses the `split` function to separate the date `String` from the seat data
into year, month, and day `Strings`.
Note::
* The use of a `String` type value to `char` type value
<<string-character-casting, cast>> as part of the second argument since
character literals do not exist.
* The use of the `ctx` ingest processor context variable to retrieve the
data from the `date` field.
<8> Appends the <<string-literals, string literal>> `"0"` value to a single
digit month since the format of the seat data allows for this case.
<9> Appends the <<string-literals, string literal>> `"0"` value to a single
digit day since the format of the seat data allows for this case.
<10> Sets the <<primitive-types, `boolean type`>>
<<painless-variables, variable>> to `true` if the time `String` is a time
in the afternoon or evening.
Note::
* The use of the `ctx` ingest processor context variable to retrieve the
data from the `time` field.
<11> Uses the `split` function to separate the time `String` from the seat data
into hours and minutes `Strings`.
Note::
* The use of the `substring` method to remove the `AM` or `PM` portion of
the time `String`.
* The use of a `String` type value to `char` type value
<<string-character-casting, cast>> as part of the second argument since
character literals do not exist.
* The use of the `ctx` ingest processor context variable to retrieve the
data from the `date` field.
<12> If the time `String` is an afternoon or evening value adds the
<<integer-literals, integer literal>> `12` to the existing hours to move to
a 24-hour based time.
<13> Builds a new time `String` that is parsable using existing API methods.
<14> Creates a `ZonedDateTime` <<reference-types, reference type>> value by using
the API method `parse` to parse the new time `String`.
<15> Sets the datetime field `datetime` to the number of milliseconds retrieved
from the API method `getLong`.
Note::
* The use of the `ctx` ingest processor context variable to set the field
`datetime`. Manipulate each document's fields with the `ctx` variable as
each document is indexed.
Submit the following request:
[source,js]
----
PUT /_ingest/pipeline/seats
{
"description": "update datetime for seats",
"processors": [
{
"script": {
"source": "String[] split(String s, char d) { int count = 0; for (char c : s.toCharArray()) { if (c == d) { ++count; } } if (count == 0) { return new String[] {s}; } String[] r = new String[count + 1]; int i0 = 0, i1 = 0; count = 0; for (char c : s.toCharArray()) { if (c == d) { r[count++] = s.substring(i0, i1); i0 = i1 + 1; } ++i1; } r[count] = s.substring(i0, i1); return r; } String[] dateSplit = split(ctx.date, (char)\"-\"); String year = dateSplit[0].trim(); String month = dateSplit[1].trim(); if (month.length() == 1) { month = \"0\" + month; } String day = dateSplit[2].trim(); if (day.length() == 1) { day = \"0\" + day; } boolean pm = ctx.time.substring(ctx.time.length() - 2).equals(\"PM\"); String[] timeSplit = split(ctx.time.substring(0, ctx.time.length() - 2), (char)\":\"); int hours = Integer.parseInt(timeSplit[0].trim()); int minutes = Integer.parseInt(timeSplit[1].trim()); if (pm) { hours += 12; } String dts = year + \"-\" + month + \"-\" + day + \"T\" + (hours < 10 ? \"0\" + hours : \"\" + hours) + \":\" + (minutes < 10 ? \"0\" + minutes : \"\" + minutes) + \":00+08:00\"; ZonedDateTime dt = ZonedDateTime.parse(dts, DateTimeFormatter.ISO_OFFSET_DATE_TIME); ctx.datetime = dt.getLong(ChronoField.INSTANT_SECONDS)*1000L;"
}
}
]
}
----
// CONSOLE