v2.0 Planning

[jshlbrd]

@shellcromancer and I were discussing breaking changes in #215, and we've accumulated some that are worth mentioning and preparing for a small v2.0 release. This includes:

• Splitting the libsonnet file and bringing part of it in scope to SemVer (discussed in feat(transform): Add KV Store Set Add Transform #215)
• Refactoring the libsonnet functions (discussed in feat(transform): Add KV Store Set Add Transform #215)
• Removing Transform fields in all Meta* transforms (replaced by Transforms)
• Removing the MetaPipeline transform (replaced by the change above)
• Changing the default behavior of the MetaErr transform (empty err list will not catch every error)

Up for possible inclusion is removing retry functionality from each individual transform (replaced by MetaRetry transform).

[jshlbrd]

I started a v2 branch for the Brex team to work on. We should add comments to this discussion for any major changes and discuss them in a thread.

[jshlbrd]

Refactoring the Condition Package

This commit is the start of a big change, but shouldn't have much impact on v1.0 deployments. In v1.0 and previous releases the condition package uses a config schema that separates operators (any, all, none) and inspectors, which required the addition of the meta_condition inspector for complex logic (chaining ORs and ANDs or ANDs and ORs). This change simplifies the config schema so that v1.0 operators are now inspectors, which makes them easier to chain.

This is required in v1.0:

sub.cnd.all([
  sub.cnd.meta.condition({ condition: sub.cnd.any([
    sub.cnd.str.contains({value: "a"}),
    sub.cnd.str.contains({value: "b"}),
    sub.cnd.str.contains({value: "c"}),
  ]),
  sub.cnd.meta.condition({ condition: sub.cnd.none([
    sub.cnd.str.contains({value: "z"}),
  ]),
])

The equivalent in v2.0 would be:

sub.cnd.all([
  sub.cnd.any([
    sub.cnd.str.contains({value: "a"}),
    sub.cnd.str.contains({value: "b"}),
    sub.cnd.str.contains({value: "c"}),
  ]),
  sub.cnd.none([
    sub.cnd.str.contains({value: "z"}),
  ]),
])

This also removes the need for the other meta inspectors:

• meta_for_each: This behavior is now built into meta_all, meta_any, meta_none when the input is an array.
• meta_negate: This is replaced by meta_none.
• meta_err: Inspectors no longer produce errors that should be caught at runtime, so this isn't needed.

The v2.0 libsonnet uses the same shortcut as the v1.0 operators, so the migration path is "replace all" in existing configs; for example, replacing sub.cnd.meta.condition({ condition: sub.cnd.any([ with sub.cnd.any([ should be all it takes to migrate. This type of migration should be tested before v2.0 releases to confirm assumptions about simplicity in migrating.

[jshlbrd]

@shellcromancer This should address some issues we discussed about the complexity of chaining conditions, but let me know what you think.

[shellcromancer]

The simplifications to remove meta.condition look great and more intuitive to me, thanks for kicking these changes off! 👍

meta_err: Inspectors no longer produce errors that should be caught at runtime, so this isn't needed.

Will meta_err still be needed for transforms that produce errors at runtime? One example is with the the dns.ip_lookup transform like used here.

[jshlbrd]

Yeah! We're keeping the meta.err transform, but not the inspector variant. 👍

[shellcromancer]

Gotcha. I got confused by the duplicative name -- no concerns in that case!

[jshlbrd]

The v2.0.0 beta release is up and the PR to bump versions is drafted. 👍