v0.46.1

This is bugfix release to resolve an issue in the release pipeline. Everything else is
the same as 0.46.0, which contains a mix of bugfixes, optimizations, and new features:

New language feature: refs in rule heads

With this version of OPA, we can use a shorthand for defining deeply-nested structures
in Rego:

Before, we had to use multiple packages, and hence multiple files to define a structure
like this:

{
  "method": {
    "get": {
      "allowed": true
    }
    "post": {
      "allowed": true
    }
  }
}

package method.get
default allowed := false
allowed { ... }

package method.post
default allowed := false
allowed { ... }

Now, we can define those rules in single package (and file):

package method
import future.keywords.if
default get.allowed := false
get.allowed if { ... }

default post.allowed := false
post.allowed if { ... }

Note that in this example, the use of the future keyword if is mandatory
for backwards-compatibility: without it, get.allowed would be interpreted
as get["allowed"], a definition of a partial set rule.

Currently, variables may only appear in the last part of the rule head:

package method
import future.keywords.if

endpoints[ep].allowed if ep := "/v1/data" # invalid
repos.get.endpoint[x] if x := "/v1/data" # valid

The valid rule defines this structure:

{
  "method": {
    "repos": {
      "get": {
        "endpoint": {
          "/v1/data": true
        }
      }
    }
  }
}

To define a nested key-value pair, we would use

package method
import future.keywords.if

repos.get.endpoint[x] = y if {
  x := "/v1/data"
  y := "example"
}

Multi-value rules (previously referred to as "partial set rules") that are
nested like this need to use contains future keyword, to differentiate them
from the "last part is a variable" case mentioned just above:

package method
import future.keywords.contains

repos.get.endpoint contains x if x := "/v1/data"

This rule defines the same structure, but with multiple values instead of a key:

{
  "method": {
    "repos": {
      "get": {
        "endpoint": ["/v1/data"]
      }
    }
  }
}

To ensure that it's safe to build OPA policies for older OPA versions, a new
capabilities field was introduced: "features". It's a free-form string array:

{
  "features": [
    "rule_head_ref_string_prefixes"
  ]
}

If this key is not present, the compiler will reject ref-heads. This could be
case when building bundles for older OPA version using their capabilities.

Entrypoint annotations in rule metadata

It is now possible to annotate a rule with entrypoint: true, and it will
automatically be picked up by the tooling that expected --entrypoint (-e)
parameters before.

For example, to build this rego policy into a wasm module, you had to pass
an entrypoint:

package test
allow {
    input.x
}

• opa build --target wasm --entrypoint test/allow policy.rego

With the annotation:

package test

# METADATA
# entrypoint: true
allow {
    input.x
}

• opa build --target wasm policy.rego

The places where entrypoints are taken from metadata are:

1. Building optimized bundles
2. Building Wasm bundles
3. Building Plan bundles
4. Using optimization with opa eval

Knowing a module's entrypoints can also help in different analysis tasks.

New Built-in Functon: graphql.schema_is_valid

The new built-in allows checking schemas:

schema := `
  extend type User {
      id: ID!
  }
  extend type Product {
      upc: String!
  }
  union _Entity = Product | User
  extend type Query {
    entity: _Entity
  }
`
valid_schema_example {
    graphql.schema_is_valid(schema)
}

Requested by @olegroom.

New Built-in Functon: net.cidr_is_valid

The new built-in function allows checking if a string is a valid CIDR.

valid_cidr_example {
	net.cidr_is_valid("192.168.0.0/24")
}

Authored by @ricardomaraschini.

Tooling, SDK, and Runtime

• opa build: exit with failure on empty signing key (#4972) authored by @Joffref reported by @caldwecr

• opa exec: add --fail and --fail-defined flags (#5007) authored by @byronic reported by @phantlantis

• opa exec: convert slashes of explicit bundles (Windows) (#5134) reported by @peterchenadded

• opa test: check coverage limit range [0, 100] (#5284) authored by @hzliangbin reported by @aholmis

• opa build+opa check: respect capabilities for parsing, i.e. future keywords (#5323) reported by @TheLunaticScripter

• opa bench --e2e: support providing OPA config (#4899)

• opa eval: new explain mode, --explain=debug, that includes unifcations in traces (authored by @jaspervdj)

• Decision logs: Allow rule-based dropping of decision log entries (#3945) authored by @mariusblarsen and @iamatwork

• Decision Logs: Include the req_id attribute in the decision logs (#5006) reported and authored by @humbertoc-silva

• Plugins: export OpenTelemetry TracerProvider for use in plugins (authored by @vinhph0906)

Compiler + Topdown

• graph.reachable_path: fix issue with missing subpaths (#4666) authored by @fredallen-wk

• http.send: Ensure force_cache attribute ignores Date header (#4960) reported by @bartandacc

• with: Allow replacing functions with rules (#5299)

• Evaluation: Skip default functions in full extent (#5202) reported by @ericjkao

• Evaluation: capture more cases of conflicts in function evaluation (#5272)

• Rule Indexing: fix incorrect results from indexing glob.match even if output is captured (#5283)

• Planner: various correctness fixes: #5271, #5265, #5252

• Builtins: Refactor registration functions and signatures (authored by @philipaconrad)

• Compiler: Speed up typechecker when working with Refs (authored by @philipaconrad)

• Trace: add UnifyOp to tracer events (authored by @jaspervdj)

Documentation

• Envoy Tutorial: use latest proxy_init (v8)
• Envoy Plugin: Add note about new config param to skip body parsing
• Policy Reference: Add semver examples
• Contributing Code: Provide some tips for style fixes

Website + Ecosystem

• Website: Make "outdated version" banner red if looked-at version is ancient
• Ecosystem: Add CircleCI and Topaz

Miscellaneous

• Code Cleanup:

  • Don't use the deprecated ioutil functions
  • Use t.Setenv in tests
  • Use t.TempDir to create temporary test directory (authored by @Juneezee)
  • Linters: add unconvert and tenv

• internal/strvals: port helm strvals fix (CLI --set arguments), reported by @pjbgf, helm fix authored by @mattfarina

• Wasm: Update README

• Dependency bumps, notably:

  • Golang: 1.19.2 -> 1.19.3
  • golang.org/x/text 0.3.7 -> 0.4.0
  • oras.land/oras-go 1.2.0 -> 1.2.1