Column Families#

When creating a ColumnFamily, it is possible to set garbage collection rules for expired data.

By setting a rule, cells in the table matching the rule will be deleted during periodic garbage collection (which executes opportunistically in the background).

The types MaxAgeGCRule, MaxVersionsGCRule, GarbageCollectionRuleUnion and GarbageCollectionRuleIntersection can all be used as the optional gc_rule argument in the ColumnFamily constructor. This value is then used in the create() and update() methods.

These rules can be nested arbitrarily, with a MaxAgeGCRule or MaxVersionsGCRule at the lowest level of the nesting:

import datetime

max_age = datetime.timedelta(days=3)
rule1 = MaxAgeGCRule(max_age)
rule2 = MaxVersionsGCRule(1)

# Make a composite that matches anything older than 3 days **AND**
# with more than 1 version.
rule3 = GarbageCollectionIntersection(rules=[rule1, rule2])

# Make another composite that matches our previous intersection
# **OR** anything that has more than 3 versions.
rule4 = GarbageCollectionRule(max_num_versions=3)
rule5 = GarbageCollectionUnion(rules=[rule3, rule4])

User friendly container for Google Cloud Bigtable Column Family.

class google.cloud.bigtable.column_family.ColumnFamily(column_family_id, table, gc_rule=None)[source]#

Bases: object

Representation of a Google Cloud Bigtable Column Family.

We can use a ColumnFamily to:

create() itself
update() itself
delete() itself

Parameters:	column_family_id (str) – The ID of the column family. Must be of the form `[_a-zA-Z0-9][-_.a-zA-Z0-9]`. table* (`Table`) – The table that owns the column family. gc_rule (`GarbageCollectionRule`) – (Optional) The garbage collection settings for this column family.

create()[source]#: Create this column family.

delete()[source]#: Delete this column family.

name#

Column family name used in requests.

Note

This property will not change if column_family_id does not, but the return value is not cached.

The table name is of the form

"projects/../zones/../clusters/../tables/../columnFamilies/.."

Return type:	str
Returns:	The column family name.

to_pb()[source]#

Converts the column family to a protobuf.

Return type:	`table_v2_pb2.ColumnFamily`
Returns:	The converted current object.

update()[source]#: Update this column family.

Note

Only the GC rule can be updated. By changing the column family ID, you will simply be referring to a different column family.

class google.cloud.bigtable.column_family.GCRuleIntersection(rules)[source]#

Bases: google.cloud.bigtable.column_family.GarbageCollectionRule

Intersection of garbage collection rules.

Parameters:	rules (list) – List of `GarbageCollectionRule`.

to_pb()[source]#

Converts the intersection into a single GC rule as a protobuf.

Return type:	`table_v2_pb2.GcRule`
Returns:	The converted current object.

class google.cloud.bigtable.column_family.GCRuleUnion(rules)[source]#

Bases: google.cloud.bigtable.column_family.GarbageCollectionRule

Union of garbage collection rules.

Parameters:	rules (list) – List of `GarbageCollectionRule`.

to_pb()[source]#

Converts the union into a single GC rule as a protobuf.

Return type:	`table_v2_pb2.GcRule`
Returns:	The converted current object.

class google.cloud.bigtable.column_family.GarbageCollectionRule[source]#

Bases: object

Garbage collection rule for column families within a table.

Cells in the column family (within a table) fitting the rule will be deleted during garbage collection.

Note

This class is a do-nothing base class for all GC rules.

Note

A string gc_expression can also be used with API requests, but that value would be superceded by a gc_rule. As a result, we don’t support that feature and instead support via native classes.

class google.cloud.bigtable.column_family.MaxAgeGCRule(max_age)[source]#

Bases: google.cloud.bigtable.column_family.GarbageCollectionRule

Garbage collection limiting the age of a cell.

Parameters:	max_age (`datetime.timedelta`) – The maximum age allowed for a cell in the table.

to_pb()[source]#

Converts the garbage collection rule to a protobuf.

Return type:	`table_v2_pb2.GcRule`
Returns:	The converted current object.

class google.cloud.bigtable.column_family.MaxVersionsGCRule(max_num_versions)[source]#

Bases: google.cloud.bigtable.column_family.GarbageCollectionRule

Garbage collection limiting the number of versions of a cell.

Parameters:	max_num_versions (int) – The maximum number of versions

to_pb()[source]#

Converts the garbage collection rule to a protobuf.

Return type:	`table_v2_pb2.GcRule`
Returns:	The converted current object.