Find the structure of a text file

  • POST /_text_structure/find_structure
Auth

The text file must contain data that is suitable to be ingested into Elasticsearch.

This API provides a starting point for ingesting data into Elasticsearch in a format that is suitable for subsequent use with other Elastic Stack functionality. Unlike other Elasticsearch endpoints, the data that is posted to this endpoint does not need to be UTF-8 encoded and in JSON format. It must, however, be text; binary text formats are not currently supported. The size is limited to the Elasticsearch HTTP receive buffer size, which defaults to 100 Mb.

The response from the API contains:

  • A couple of messages from the beginning of the text.
  • Statistics that reveal the most common values for all fields detected within the text and basic numeric statistics for numeric fields.
  • Information about the structure of the text, which is useful when you write ingest configurations to index it or similarly formatted text.
  • Appropriate mappings for an Elasticsearch index, which you could use to ingest the text.

All this information can be calculated by the structure finder with no guidance. However, you can optionally override some of the decisions about the text structure by specifying one or more query parameters.

Required authorization

Cluster privileges monitor_text_structure

Query parameters

charset string

The text's character set. It must be a character set that is supported by the JVM that Elasticsearch uses. For example, UTF-8, UTF-16LE, windows-1252, or EUC-JP. If this parameter is not specified, the structure finder chooses an appropriate character set.

column_names string

If you have set format to delimited, you can specify the column names in a comma-separated list. If this parameter is not specified, the structure finder uses the column names from the header row of the text. If the text does not have a header role, columns are named "column1", "column2", "column3", for example.

delimiter string

If you have set format to delimited, you can specify the character used to delimit the values in each row. Only a single character is supported; the delimiter cannot have multiple characters. By default, the API considers the following possibilities: comma, tab, semi-colon, and pipe (|). In this default scenario, all rows must have the same number of fields for the delimited format to be detected. If you specify a delimiter, up to 10% of the rows can have a different number of columns than the first row.

ecs_compatibility string · default: disabled

The mode of compatibility with ECS compliant Grok patterns. Use this parameter to specify whether to use ECS Grok patterns instead of legacy ones when the structure finder creates a Grok pattern. Valid values are disabled and v1. This setting primarily has an impact when a whole message Grok pattern such as %{CATALINALOG} matches the input. If the structure finder identifies a common structure but has no idea of meaning then generic field names such as path, ipaddress, field1, and field2 are used in the grok_pattern output, with the intention that a user who knows the meanings rename these fields before using it.

explain boolean · default: false

If this parameter is set to true, the response includes a field named explanation, which is an array of strings that indicate how the structure finder produced its result. If the structure finder produces unexpected results for some text, use this query parameter to help you determine why the returned structure was chosen.

format enum

The high level structure of the text. Valid values are ndjson, xml, delimited, and semi_structured_text. By default, the API chooses the format. In this default scenario, all rows must have the same number of fields for a delimited format to be detected. If the format is set to delimited and the delimiter is not set, however, the API tolerates up to 5% of rows that have a different number of columns than the first row.

Values: ndjson xml delimited semi_structured_text
grok_pattern string

If you have set format to semi_structured_text, you can specify a Grok pattern that is used to extract fields from every message in the text. The name of the timestamp field in the Grok pattern must match what is specified in the timestamp_field parameter. If that parameter is not specified, the name of the timestamp field in the Grok pattern must match "timestamp". If grok_pattern is not specified, the structure finder creates a Grok pattern.

has_header_row boolean

If you have set format to delimited, you can use this parameter to indicate whether the column names are in the first row of the text. If this parameter is not specified, the structure finder guesses based on the similarity of the first row of the text to other rows.

line_merge_size_limit number · default: 10000

The maximum number of characters in a message when lines are merged to form messages while analyzing semi-structured text. If you have extremely long messages you may need to increase this, but be aware that this may lead to very long processing times if the way to group lines into messages is misdetected.

lines_to_sample number · default: 1000

The number of lines to include in the structural analysis, starting from the beginning of the text. The minimum is 2. If the value of this parameter is greater than the number of lines in the text, the analysis proceeds (as long as there are at least two lines in the text) for all of the lines.

Note

The number of lines and the variation of the lines affects the speed of the analysis. For example, if you upload text where the first 1000 lines are all variations on the same message, the analysis will find more commonality than would be seen with a bigger sample. If possible, however, it is more efficient to upload sample text with more variety in the first 1000 lines than to request analysis of 100000 lines to achieve some variety.

quote string

If you have set format to delimited, you can specify the character used to quote the values in each row if they contain newlines or the delimiter character. Only a single character is supported. If this parameter is not specified, the default value is a double quote ("). If your delimited text format does not use quoting, a workaround is to set this argument to a character that does not appear anywhere in the sample.

should_trim_fields boolean

If you have set format to delimited, you can specify whether values between delimiters should have whitespace trimmed from them. If this parameter is not specified and the delimiter is pipe (|), the default value is true. Otherwise, the default value is false.

timeout string · default: 25s

The maximum amount of time that the structure analysis can take. If the analysis is still running when the timeout expires then it will be stopped.

timestamp_field string

The name of the field that contains the primary timestamp of each record in the text. In particular, if the text were ingested into an index, this is the field that would be used to populate the @timestamp field.

If the format is semi_structured_text, this field must match the name of the appropriate extraction in the grok_pattern. Therefore, for semi-structured text, it is best not to specify this parameter unless grok_pattern is also specified.

For structured text, if you specify this parameter, the field must exist within the text.

If this parameter is not specified, the structure finder makes a decision about which field (if any) is the primary timestamp field. For structured text, it is not compulsory to have a timestamp in the text.

timestamp_format string

The Java time format of the timestamp field in the text.

Only a subset of Java time format letter groups are supported:

  • a
  • d
  • dd
  • EEE
  • EEEE
  • H
  • HH
  • h
  • M
  • MM
  • MMM
  • MMMM
  • mm
  • ss
  • XX
  • XXX
  • yy
  • yyyy
  • zzz

Additionally S letter groups (fractional seconds) of length one to nine are supported providing they occur after ss and separated from the ss by a ., , or :. Spacing and punctuation is also permitted with the exception of ?, newline and carriage return, together with literal text enclosed in single quotes. For example, MM/dd HH.mm.ss,SSSSSS 'in' yyyy is a valid override format.

One valuable use case for this parameter is when the format is semi-structured text, there are multiple timestamp formats in the text, and you know which format corresponds to the primary timestamp, but you do not want to specify the full grok_pattern. Another is when the timestamp format is one that the structure finder does not consider by default.

If this parameter is not specified, the structure finder chooses the best format from a built-in set.

If the special value null is specified the structure finder will not look for a primary timestamp in the text. When the format is semi-structured text this will result in the structure finder treating the text as single-line messages.

Request body

Type: object[]

Response

application/json
charset string required

The character encoding used to parse the text.

has_header_row boolean
has_byte_order_marker boolean required

For UTF character encodings, it indicates whether the text begins with a byte order marker.

format string required

Valid values include ndjson, xml, delimited, and semi_structured_text.

field_stats map string to object required

The most common values of each field, plus basic numeric statistics for the numeric page_count field. This information may provide clues that the data needs to be cleaned or transformed prior to use by other Elastic Stack functionality.

<string> object
count number required
cardinality number required
top_hits object[] required
count number required
value object required
mean_value number
median_value number
max_value number
min_value number
earliest string
latest string
sample_start string required

The first two messages in the text verbatim. This may help diagnose parse errors or accidental uploads of the wrong text.

num_messages_analyzed number required

The number of distinct messages the lines contained. For NDJSON, this value is the same as num_lines_analyzed. For other text formats, messages can span several lines.

mappings object required

Some suitable mappings for an index into which the data could be ingested.

all_field object
analyzer string required
enabled boolean required
omit_norms boolean required
search_analyzer string required
similarity string required
store boolean required
store_term_vector_offsets boolean required
store_term_vector_payloads boolean required
store_term_vector_positions boolean required
store_term_vectors boolean required
date_detection boolean
dynamic enum
Values: strict runtime true false
dynamic_date_formats string[]
dynamic_templates string to object[]
_field_names object
enabled boolean required
index_field object
enabled boolean required
_meta object
numeric_detection boolean
properties map string to oneOf
_routing object
required boolean required
_size object
enabled boolean required
_source object
compress boolean
compress_threshold string
enabled boolean
excludes string[]
includes string[]
mode enum

Supported values include:

  • disabled
  • stored
  • synthetic: Instead of storing source documents on disk exactly as you send them, Elasticsearch can reconstruct source content on the fly upon retrieval.
Values: disabled stored synthetic
runtime map string to object
<string> object
fields map string to object

For type composite

<string> object
type enum required
Values: boolean composite date double geo_point geo_shape ip keyword long lookup
fetch_fields object[]

For type lookup

field string required
format string
format string

A custom format for date type runtime fields.

input_field string

For type lookup

target_field string

For type lookup

target_index string

For type lookup

script string

Painless script executed at query time.

on_script_error enum
Values: fail continue
type enum required

Field type, which can be: boolean, composite, date, double, geo_point, ip,keyword, long, or lookup.

Values: boolean composite date double geo_point geo_shape ip keyword long lookup
enabled boolean
subobjects enum
Values: true false
_data_stream_timestamp object
enabled boolean required
quote string
delimiter string
need_client_timezone boolean required

If a timestamp format is detected that does not include a timezone, need_client_timezone is true. The server that parses the text must therefore be told the correct timezone by the client.

num_lines_analyzed number required

The number of lines of the text that were analyzed.

column_names string[]

If format is delimited, the column_names field lists the column names in the order they appear in the sample.

explanation string[]
grok_pattern string
multiline_start_pattern string
exclude_lines_pattern string
java_timestamp_formats string[]

The Java time formats recognized in the time fields. Elasticsearch mappings and ingest pipelines use this format.

joda_timestamp_formats string[]

Information that is used to tell Logstash how to parse timestamps.

timestamp_field string

The field considered most likely to be the primary timestamp of each document.

should_trim_fields boolean
ingest_pipeline object required
description string

Description of the ingest pipeline.

version number

Version number used by external systems to track ingest pipelines.

processors {} Processor[] required

Processors used to perform transformations on documents before indexing. Processors run sequentially in the order specified.