terraform/helper/schema
Chris Marchesi 3fa11e456b
helper/schema: Clear existing map/set/list contents before overwriting
There are situations where one may need to write to a set, list, or map
more than once per single TF operation (apply/refresh/etc). In these
cases, further writes using Set (example: d.Set("some_set", newSet))
currently create unstable results in the set writer (the name of the
writer layer that holds the data set by these calls) because old keys
are not being cleared out first.

This bug is most visible when using sets. Example: First write to set
writes elements that have been hashed at 10 and 20, and the second write
writes elements that have been hashed at 30 and 40. While the set length
has been correctly set at 2, since a set is basically a map (as is the
entire map writer) and map results are non-deterministic, reads to this
set will now deliver unstable results in a random but predictable
fashion as the map results are delivered to the caller non-deterministic
- sometimes you may correctly get 30 and 40, but sometimes you may get
10 and 20, or even 10 and 30, etc.

This problem propagates to state which is even more damaging as unstable
results are set to state where they become part of the permanent data
set going forward.

The problem also applies to lists and maps. This is probably more of an
issue with maps as a map can contain any key/value combination and hence
there is no predictable pattern where keys would be overwritten with
default or zero values. This is contrary to complex lists, which has
this problem as well, but since lists are deterministic and the length
of a list properly gets updated during the overwrite, the problem is
masked by the fact that a read will only read to the boundary of the
list, skipping any bad data that may still be available due past the
list boundary.

This update clears the child contents of any set, list, or map before
beginning a new write to address this issue. Tests are included for all
three data types.
2017-11-05 12:04:23 -08:00
..
README.md helper/schema: README 2014-08-17 20:51:09 -07:00
backend.go helper/schema: Hook CustomizeDiffFunc into diff logic 2017-11-01 14:25:32 -07:00
backend_test.go helper/schema: framework for Backends 2017-01-26 14:33:49 -08:00
core_schema.go core: terraform.ResourceProvider.GetSchema method 2017-10-17 07:23:41 -07:00
core_schema_test.go core: terraform.ResourceProvider.GetSchema method 2017-10-17 07:23:41 -07:00
data_source_resource_shim.go helper/schema: emit warning when using data source resource shim 2016-05-14 08:26:36 -07:00
equal.go helper/schema: use interface for equality check 2015-01-16 09:32:15 -08:00
field_reader.go Check for interpolated values when reading a map 2016-11-28 09:04:24 -05:00
field_reader_config.go helper/schema: PromoteSingle for legacy support of "maybe list" types 2017-01-26 15:09:15 -08:00
field_reader_config_test.go Check for interpolated values when reading a map 2016-11-28 09:04:24 -05:00
field_reader_diff.go memoize DiffFieldReader.ReadField 2017-07-28 14:26:36 -04:00
field_reader_diff_test.go Allow primitive type in maps via all FieldReaders 2016-11-17 15:35:08 -05:00
field_reader_map.go Allow primitive type in maps via all FieldReaders 2016-11-17 15:35:08 -05:00
field_reader_map_test.go Allow primitive type in maps via all FieldReaders 2016-11-17 15:35:08 -05:00
field_reader_multi.go helper/schema: full object test for addrToSchema 2015-01-09 17:43:44 -08:00
field_reader_multi_test.go Revert "helper/schema: Make nested Set(s) in List(s) work" (#7436) 2016-06-30 10:48:52 -05:00
field_reader_test.go Allow primitive type in maps via all FieldReaders 2016-11-17 15:35:08 -05:00
field_writer.go helper/schema: FieldWriter, replace Set 2015-01-10 11:44:26 -08:00
field_writer_map.go helper/schema: Clear existing map/set/list contents before overwriting 2017-11-05 12:04:23 -08:00
field_writer_map_test.go helper/schema: Clear existing map/set/list contents before overwriting 2017-11-05 12:04:23 -08:00
getsource_string.go Fix stringer comments (#15069) 2017-06-05 10:17:35 +01:00
provider.go helper/schema: Hook CustomizeDiffFunc into diff logic 2017-11-01 14:25:32 -07:00
provider_test.go core: terraform.ResourceProvider.GetSchema method 2017-10-17 07:23:41 -07:00
provisioner.go helper/schema: Hook CustomizeDiffFunc into diff logic 2017-11-01 14:25:32 -07:00
provisioner_test.go Refactor the provisioner validation function (#15273) 2017-06-15 19:57:04 +02:00
resource.go helper/schema: CustomizeDiff allowed on writable resources only 2017-11-01 15:42:24 -07:00
resource_data.go Rename to GetOkExists 2017-08-03 12:05:19 -04:00
resource_data_get_source.go helper/schema: diff with set going to 0 elements removes it from state 2015-02-17 11:38:56 -08:00
resource_data_test.go update tests 2017-08-03 17:53:07 -04:00
resource_diff.go helper/schema: Add behaviour detail to various custom diff comments 2017-11-01 15:42:24 -07:00
resource_diff_test.go helper/schema: Better ResourceDiff schema key validation 2017-11-01 14:25:32 -07:00
resource_importer.go helper/schema: pass through import state func 2016-05-16 10:03:57 -07:00
resource_test.go helper/schema: CustomizeDiff allowed on writable resources only 2017-11-01 15:42:24 -07:00
resource_timeout.go helper/schema: Rename Timeout resource block to Timeouts (#12533) 2017-03-09 14:40:14 -06:00
resource_timeout_test.go helper/schema: Rename Timeout resource block to Timeouts (#12533) 2017-03-09 14:40:14 -06:00
schema.go helper/schema: Review -> CustomizeDiff 2017-11-01 14:25:32 -07:00
schema_test.go helper/schema: Review -> CustomizeDiff 2017-11-01 14:25:32 -07:00
serialize.go core: Avoid crash on empty TypeSet blocks (#14305) 2017-05-09 20:45:53 +02:00
serialize_test.go Add test for TypeMap in a Schema 2016-06-09 16:00:33 -04:00
set.go helper/schema: Add Set.HashEqual 2017-08-15 21:50:52 -07:00
set_test.go helper/schema: More tests for Set.HashEqual 2017-08-15 21:56:01 -07:00
testing.go helper/schema: Hook CustomizeDiffFunc into diff logic 2017-11-01 14:25:32 -07:00
valuetype.go helper/schema: zero value of a set should be empty 2015-02-17 16:58:47 -08:00
valuetype_string.go Fix stringer comments (#15069) 2017-06-05 10:17:35 +01:00

README.md

Terraform Helper Lib: schema

The schema package provides a high-level interface for writing resource providers for Terraform.

If you're writing a resource provider, we recommend you use this package.

The interface exposed by this package is much friendlier than trying to write to the Terraform API directly. The core Terraform API is low-level and built for maximum flexibility and control, whereas this library is built as a framework around that to more easily write common providers.