Cloud Bigtable API - Class Google::Cloud::Bigtable::RowFilter::ChainFilter (v2.8.0)

Reference documentation and code samples for the Cloud Bigtable API class Google::Cloud::Bigtable::RowFilter::ChainFilter.

ChainFilter

A RowFilter that sends rows through several RowFilters in sequence.

The elements of "filters" are chained together to process the input row:

in row -> f(0) -> intermediate row -> f(1) -> ... -> f(N) -> out row

The full chain is executed atomically.

Inherits

  • Object

Example

require "google/cloud/bigtable"

chain = Google::Cloud::Bigtable::RowFilter.chain
# Add filters to chain filter
chain.key("user-*").label "users"

Methods

#block

def block() -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a block-all filter.

Does not match any cells, regardless of input. Useful for temporarily disabling just part of a filter.

Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.block

#cells_per_column

def cells_per_column(limit) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a cells-per-column filter.

Matches only the most recent N cells within each column. For example, if N=2, this filter would match column foo:bar at timestamps 10 and 9, skip all earlier cells in foo:bar, and then begin matching again in column foo:bar2. If duplicate cells are present, as is possible when using an Interleave, each copy of the cell is counted separately.

Parameter
  • limit (String) — Max cell match per column limit.
Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.cells_per_column 5

#cells_per_row

def cells_per_row(limit) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a cells-per-row-limit filter.

Matches only the first N cells of each row. If duplicate cells are present, as is possible when using an Interleave, each copy of the cell is counted separately.

Parameter
  • limit (String) — Max cell match per row limit.
Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.cells_per_row 5

#cells_per_row_offset

def cells_per_row_offset(offset) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a cell-per-row-offset filter instance to skip the first N cells.

Skips the first N cells of each row, matching all subsequent cells. If duplicate cells are present, as is possible when using an Interleave, each copy of the cell is counted separately.

Parameter
  • offset (Integer) — Offset value.
Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.cells_per_row_offset 3

#chain

def chain(filter) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a chain filter.

A Chain RowFilter that sends rows through several RowFilters in sequence.

The elements of "filters" are chained together to process the input row:

in row -> f(0) -> intermediate row -> f(1) -> ... -> f(N) -> out row

The full chain is executed atomically.

Parameter
Returns
Raises
Example

Create a chain filter and add a chain filter.

require "google/cloud/bigtable"

chain_1 = Google::Cloud::Bigtable::RowFilter.chain

# Add filters to chain filter
chain_1.key("user-*").cells_per_row 5

filter = Google::Cloud::Bigtable::RowFilter.chain
filter.chain chain_1

# OR
filter = Google::Cloud::Bigtable::RowFilter.chain.chain chain_1

#column_range

def column_range(range) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a column-range filter.

Matches only cells from columns within the given range.

Parameter
Returns
Example 
require "google/cloud/bigtable"

range = Google::Cloud::Bigtable::ColumnRange.new("cf").from("field0").to("field5")

filter = Google::Cloud::Bigtable::RowFilter.chain.column_range range

#condition

def condition(filter) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a condition filter.

A RowFilter that evaluates one of two possible RowFilters, depending on whether or not a predicate RowFilter outputs any cells from the input row.

IMPORTANT NOTE: The predicate filter does not execute atomically with the true and false filters, which may lead to inconsistent or unexpected results. Additionally, condition filters have poor performance, especially when filters are set for the false condition.

Cannot be used within the predicate_filter, true_filter, or false_filter.

Parameter
Returns
Raises
Example 
require "google/cloud/bigtable"

predicate = Google::Cloud::Bigtable::RowFilter.key "user-*"

label = Google::Cloud::Bigtable::RowFilter.label "user"
strip_value = Google::Cloud::Bigtable::RowFilter.strip_value

condition_filter = Google::Cloud::Bigtable::RowFilter.condition(predicate)
                                                     .on_match(label)
                                                     .otherwise(strip_value)

filter = Google::Cloud::Bigtable::RowFilter.chain.condition condition_filter

#family

def family(regex) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a family-name-match filter using a regular expression.

Matches only cells from columns whose families satisfy the given RE2 regex. For technical reasons, the regex must not contain the : character, even if it is not being used as a literal. Note that, since column families cannot contain the new line character \n, it is sufficient to use . as a full wildcard when matching column family names.

For Regex syntax:

Parameter
  • regex (String) — Regex to match family name.
Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.family "cf-*"

#filters

def filters() -> Array<SimpleFilter|ChainFilter|InterleaveFilter|ConditionFilter>

Returns a frozen copy of the filters array.

Returns
  • (Array<SimpleFilter|ChainFilter|InterleaveFilter|ConditionFilter>)

#interleave

def interleave(filter) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds an interleave filter.

A RowFilter that sends each row to each of several component RowFilters and interleaves the results.

The elements of "filters" all process a copy of the input row, and the results are pooled, sorted, and combined into a single output row. If multiple cells are produced with the same column and timestamp, they will all appear in the output row in an unspecified mutual order. Consider the following example, with three filters:

                             input row
                                 |
       -----------------------------------------------------
       |                         |                         |
      f(0)                      f(1)                      f(2)
       |                         |                         |
1: foo,bar,10,x             foo,bar,10,z              far,bar,7,a
2: foo,blah,11,z            far,blah,5,x              far,blah,5,x
       |                         |                         |
       -----------------------------------------------------
                                 |
1:                      foo,bar,10,z   # could have switched with #2
2:                      foo,bar,10,x   # could have switched with #1
3:                      foo,blah,11,z
4:                      far,bar,7,a
5:                      far,blah,5,x   # identical to #6
6:                      far,blah,5,x   # identical to #5

All interleaved filters are executed atomically.

See InterleaveFilter

Parameter
Returns
Raises
Example

Add an interleave filter to the chain filter.

require "google/cloud/bigtable"

interleave = Google::Cloud::Bigtable::RowFilter.interleave

# Add filters to interleave filter
interleave.key("user-*").cells_per_column(3)

chain = Google::Cloud::Bigtable::RowFilter.chain.interleave interleave

#key

def key(regex) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a key-filter instance to match keys using a regular expression.

Matches only cells from rows whose keys satisfy the given RE2 regex. In other words, passes through the entire row when the key matches, and otherwise produces an empty row. Note that, since row keys can contain arbitrary bytes, the \C escape sequence must be used if a true wildcard is desired. The . character will not match the new line character \n, which may be present in a binary key.

For Regex syntax:

Parameter
  • regex (String) — Regex to match row keys.
Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.key "user-*"

#label

def label(value) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a label filter instance to apply a label based on the result of read rows.

Applies the given label to all cells in the output row. This allows the client to determine which results were produced from which part of the filter.

Values must be at most 15 characters and match the RE2 pattern [a-z0-9\-]+

Due to a technical limitation, it is not possible to apply multiple labels to a cell. As a result, a chain may have no more than one sub-filter that contains an apply_label_transformer. It is okay for an Interleave to contain multiple apply_label_transformers, as they will be applied to separate copies of the input.

Parameter
  • value (String) — Label name
Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.label "user-detail"

#length

def length() -> Integer

Gets the number of filters in the chain.

Returns
  • (Integer)
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.key("user-1*").label("user")
filter.length # 2

#pass

def pass() -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a pass filter.

Matches all cells, regardless of input. Functionally equivalent to leaving filter unset, but included for completeness.

Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.pass

#qualifier

def qualifier(regex) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a column-qualifier-match filter using a regular expression.

Matches only cells from columns whose qualifiers satisfy the given RE2 regex. Note that, since column qualifiers can contain arbitrary bytes, the \C escape sequence must be used if a true wildcard is desired. The . character will not match the new line character \n, which may be present in a binary qualifier.

For Regex syntax:

Parameter
  • regex (String) — Regex to match column qualifier name.
Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.qualifier "user-name*"

#sample

def sample(probability) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a sample-probability filter.

Matches all cells from a row with probability p, and matches no cells from the row with probability 1-p.

Parameter
  • probability (Float) — Probability value. Probability must be greater than 0 and less than 1.0.
Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.sample 0.5

#sink

def sink() -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a sink filter.

Outputs all cells directly to the output of the read rather than to any parent filter.

Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.sink

#strip_value

def strip_value() -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a strip-value filter.

Replaces each cell's value with an empty string.

Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.strip_value

#timestamp_range

def timestamp_range(from: nil, to: nil) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a timestamp-range filter.

Matches only cells with timestamps within the given range. Specifies a contiguous range of timestamps.

Parameters
  • from (Integer) (defaults to: nil) — Inclusive lower bound. If left empty, interpreted as 0.
  • to (Integer) (defaults to: nil) — Exclusive upper bound. If left empty, interpreted as infinity.
Returns
Example 
require "google/cloud/bigtable"

timestamp_micros = (Time.now.to_f * 1_000_000).round(-3)
from = timestamp_micros - 300_000_000
to = timestamp_micros

filter = Google::Cloud::Bigtable::RowFilter.chain.timestamp_range from: from, to: to

#value

def value(regex) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a value-match filter using a regular expression.

Matches only cells with values that satisfy the given regular expression. Note that, since cell values can contain arbitrary bytes, the \C escape sequence must be used if a true wildcard is desired. The . character will not match the new line character \n, which may be present in a binary value.

For Regex syntax:

Parameter
  • regex (String) — Regex to match cell value.
Returns
Example 
require "google/cloud/bigtable"

filter = Google::Cloud::Bigtable::RowFilter.chain.value "abc*"

#value_range

def value_range(range) -> Google::Cloud::Bigtable::RowFilter::ChainFilter

Adds a value-range filter.

Matches only cells with values that fall within the given range.

See ValueRange#from and { Google::Cloud::Bigtable::ValueRange#to} for range option inclusive/exclusive options.

  • The value at which to start the range. If neither field is set, interpreted as an empty string, inclusive.
  • The value at which to end the range. If neither field is set, interpreted as the infinite string, exclusive.
Parameter
Returns
Examples

Start to end range.

require "google/cloud/bigtable"

bigtable = Google::Cloud::Bigtable.new
table = bigtable.table "my-instance", "my-table"

range = table.new_value_range.from("value-001").to("value-005")
filter = Google::Cloud::Bigtable::RowFilter.chain.value_range range

Start exclusive to infinite end range.

require "google/cloud/bigtable"

bigtable = Google::Cloud::Bigtable.new
table = bigtable.table "my-instance", "my-table"

range = table.new_value_range.from "value-001", inclusive: false
filter = Google::Cloud::Bigtable::RowFilter.chain.value_range range