Prepare v0.45.0 release (#5223)

* Prepare v0.45.0 release

Signed-off-by: Philip Conrad <philipaconrad@gmail.com>

CHANGELOG.md

@@ -3,7 +3,159 @@
 All notable changes to this project will be documented in this file. This
 project adheres to [Semantic Versioning](http://semver.org/).
 
-## Unreleased
+## 0.45.0
+
+This release contains a mix of bugfixes, optimizations, and new features.
+
+### Improved Decision Logging with `nd_builtin_cache`
+
+OPA has several non-deterministic built-ins, such as `rand.intn` and
+`http.send` that can make debugging policies from decision log results
+a surprisingly tricky and involved process. To improve the situation
+around debugging policies that use those built-ins, OPA now provides
+an opt-in system for caching the inputs and outputs of these built-ins
+during policy evaluation, and can include this information in decision
+log entries.
+
+A new top-level config key is used to enable the non-deterministic
+builtin caching feature, as shown below:
+
+    nd_builtin_cache: true
+
+This data is exposed to OPA's [decision log masking system](https://www.openpolicyagent.org/docs/v0.45.0/management-decision-logs/#masking-sensitive-data)
+under the `/nd_builtin_cache` path, which allows masking or dropping
+sensitive values from decision logs selectively. This can be useful
+in situations where only some information about a non-deterministic
+built-in was needed, or the arguments to the built-in involved
+sensitive data.
+
+To prevent unexpected decision log size growth from non-deterministic
+built-ins like `http.send`, the new cache information is included in
+decision logs on a best-effort basis. If a decision log event exceeds
+the `decision_logs.reporting.upload_size_limit_bytes` limit for an OPA
+instance, OPA will reattempt uploading it, after dropping the non-
+deterministic builtin cache information from the event. This behavior
+will trigger a log error when it happens, and will increment the
+`decision_logs_nd_builtin_cache_dropped` metrics counter, so that it
+will be possible to debug cases where the cache information is unexpectedly
+missing from a decision log entry.
+
+#### Decision Logging Example
+
+To observe the change in decision logging we can run OPA in server mode
+with `nd_builtin_cache` enabled:
+
+```bash
+opa run -s --set=decision_logs.console=true,nd_builtin_cache=true
+```
+
+After sending it the query `x := rand.intn("a", 15)` we should see
+something like the following in the decision logs:
+
+```
+{..., "msg":"Decision Log", "nd_builtin_cache":{"rand.intn":{"[\"a\",15]":3}}, "query":"assign(x, rand.intn(\"a\", 15))", ..., "result":[{"x":3}], ..., "type":"openpolicyagent.org/decision_logs"}
+```
+
+The new information is included under the optional `nd_builtin_cache`
+JSON key, and shows what arguments were provided for each unique
+invocation of `rand.intn`, as well as what the output of that builtin
+call was (in this case, `3`).
+
+If we sent the query `x := rand.intn("a", 15); y := rand.intn("b", 150)"`
+we can see how unique input arguments get recorded in the cache:
+
+```
+{..., "msg":"Decision Log", "nd_builtin_cache":{"rand.intn":{"[\"a\",15]":12,"[\"b\",150]":149}}, "query":"assign(x, rand.intn(\"a\", 15)); assign(y, rand.intn(\"b\", 150))", ..., "result":[{"x":12,"y":149}], ..., "type":"openpolicyagent.org/decision_logs"}
+```
+
+With this information, it's now easier to debug exactly why a particular
+rule is used or why a rule fails when non-deterministic builtins are used in
+a policy.
+
+### New Built-in Function: `regex.replace`
+
+This release introduces a new builtin for regex-based search/replace on
+strings: `regex.replace`.
+
+See [the built-in functions docs for all the details](https://www.openpolicyagent.org/docs/v0.45.0/policy-reference/#builtin-regex-regexreplace)
+
+This implementation fixes [#5162](https://github.com/open-policy-agent/opa/issues/5162) and was authored by @boranx.
+
+### `object.union_n` Optimization
+
+The `object.union_n` builtin allows easily merging together an array of Objects.
+
+Unfortunately, as noted in [#4985](https://github.com/open-policy-agent/opa/issues/4985)
+its implementation generated unnecessary intermediate copies from doing
+pairwise, recursive Object merges. These pairwise merges resulted in poor
+performance for large inputs; in many cases worse than writing the
+equivalent operation in pure Rego.
+
+This release changes the `object.union_n` builtin's implementation to use
+a more efficient merge algorithm that respects the original implementation's
+sequential, left-to-right merging semantics. The `object.union_n` builtin
+now provides a 2-3x improvement in speed and memory efficiency over the pure
+Rego equivalent.
+
+### Tooling, SDK, and Runtime
+
+- cli: Fix doubled CLI hints/errors. ([#5115](https://github.com/open-policy-agent/opa/issues/5115)) authored by @ivanphdz
+- cli/test: Add capabilities flag to test command. (authored by @ivanphdz)
+- fmt: Fix blank lines after multiline expressions. (authored by @jaspervdj)
+- internal/report: Include heap usage in the telemetry report.
+- plugins/logs: Improve error message when decision log chunk size is greater than the upload limit. ([#5155](https://github.com/open-policy-agent/opa/issues/5155))
+- ir: Make the `internal/ir` package public as `ir`.
+
+### Rego
+
+- ast/parser+formatter: Allow 'if' in rule 'else' statements.
+- ast/schema: Add support for recursive json schema elements. ([#5166](https://github.com/open-policy-agent/opa/issues/5166)) authored and reported by @liamg
+- ast/schema: Fix race condition in parsing with reused references.(authored by @liamg)
+- internal/gojsonschema: Fix race condition in `SetAllowNet`. ([#5187](https://github.com/open-policy-agent/opa/issues/5187)) authored and reported by @liamg
+- ast/compiler: Rewrite declared variables in function calls and recursively rewrite local variables in `with` clauses. ([#5148](https://github.com/open-policy-agent/opa/issues/5148)) authored and reported by @liu-du
+- ast: Skip rules when parsing a body (or query) to help improve ambiguous parsing cases.
+
+### Topdown
+
+- topdown/object: Rework `object.union_n` to use in-place merge algorithm. (reported by @charlesdaniels)
+- topdown/jwt_decode_verify: Ensure `exp` and `nbf` fields are numbers when present. ([#5165](https://github.com/open-policy-agent/opa/issues/5165)) authored and reported by @charlieflowers
+- topdown: Fix `InterQueryCache` only dropping one entry when over the size limit. (authored by @vinhph0906)
+- topdown+builtins: Block all ND builtins from partial evaluation.
+- topdown/builtins: Add Rego Object support for GraphQL builtins to improve composability.
+- topdown/json: Fix panic in `json.filter` on empty JSON paths.
+- topdown/sets_bench_test: Add `intersection` builtin tests.
+- topdown/tokens: Protect against nistec panics. ([#5128](https://github.com/open-policy-agent/opa/issues/5218))
+
+### Documentation
+
+- Add IR to integration docs.
+- Added Gloo Edge Tutorial with examples. (authored by @Parsifal-M)
+- Updated examples for CLI commands.
+- Updated section on performance metrics (authored by @hutchins)
+- docs/annotations: Add policy example and a link to the policy reference. ([#4937](https://github.com/open-policy-agent/opa/issues/4937)) authored by @Parsifal-M
+- docs/policy-language: Be more explicit about future keywords.
+- docs/security: Fix token authz example. (authored by @pigletfly)
+- docs: Update generated CLI docs. (authored by @charlieflowers)
+- docs: Update mentions of `#development` to `#contributors`. (authored by @charlieflowers)
+
+### Website + Ecosystem
+
+- website/security: Style improvements. (authored by @orweis)
+
+### Miscellaneous
+
+- ci: Add `prealloc` linter check and linter fixes.
+- ci: Add govulncheck to Nightly CI.
+- build/wasm: Use golang1.16 `go:embed` mechanism.
+- util/backoff: Seed from math/rand source.
+- version: Use `runtime/debug.BuildInfo`.
+
+- Dependency bumps, notably:
+  - build: bump golang 1.19.1 -> 1.19.2
+  - build(deps): bump golang.org/x/net
+  - build(deps): bump internal/gqlparser to v2.5.1
+  - build(deps): bump tj-actions/changed-files from 29.0.3 -> 32.0.0
+  - deps(build): bump wasmtime-go 0.36.0 -> 1.0.0 (authored by @Parsifal-M)
 
 ## 0.44.0