CHANGELOG-3.4: highlight WAL changes

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

CHANGELOG-3.4.md

@@ -33,7 +33,7 @@ See [code changes](https://github.com/coreos/etcd/compare/v3.3.0...v3.4.0) and [
 - Make etcd server return `raft.ErrProposalDropped` on internal Raft proposal drop in [v3 applier](https://github.com/coreos/etcd/pull/9549) and [v2 applier](https://github.com/coreos/etcd/pull/9558).
   - e.g. a node is removed from cluster, or [`raftpb.MsgProp` arrives at current leader while there is an ongoing leadership transfer](https://github.com/coreos/etcd/issues/8975).
 - Add [`snapshot`](https://github.com/coreos/etcd/pull/9118) package for easier snapshot workflow (see [`godoc.org/github.com/etcd/snapshot`](https://godoc.org/github.com/coreos/etcd/snapshot) for more).
-- Improve [functional tester](https://github.com/coreos/etcd/tree/master/functional) coverage: [proxy layer to run network fault tests in CI](https://github.com/coreos/etcd/pull/9081), [TLS is enabled both for server and client](https://github.com/coreos/etcd/pull/9534), [liveness mode](https://github.com/coreos/etcd/issues/9230), [shuffle test sequence](https://github.com/coreos/etcd/issues/9381), [membership reconfiguration failure cases](https://github.com/coreos/etcd/pull/9564), [disastrous quorum loss and snapshot recover from a seed member](https://github.com/coreos/etcd/pull/9565).
+- Improve [functional tester](https://github.com/coreos/etcd/tree/master/functional) coverage: [proxy layer to run network fault tests in CI](https://github.com/coreos/etcd/pull/9081), [TLS is enabled both for server and client](https://github.com/coreos/etcd/pull/9534), [liveness mode](https://github.com/coreos/etcd/issues/9230), [shuffle test sequence](https://github.com/coreos/etcd/issues/9381), [membership reconfiguration failure cases](https://github.com/coreos/etcd/pull/9564), [disastrous quorum loss and snapshot recover from a seed member](https://github.com/coreos/etcd/pull/9565), [embedded etcd](https://github.com/coreos/etcd/pull/9572).
 
 ### Breaking Changes
 
@@ -55,11 +55,6 @@ See [code changes](https://github.com/coreos/etcd/compare/v3.3.0...v3.4.0) and [
   - e.g. exit with error on `ETCDCTL_ENDPOINTS=abc.com ETCDCTL_API=3 etcdctl endpoint health --endpoints=def.com`.
 - Change [`etcdserverpb.AuthRoleRevokePermissionRequest/key,range_end` fields type from `string` to `bytes`](https://github.com/coreos/etcd/pull/9433).
 - Change [`embed.Config.CorsInfo` in `*cors.CORSInfo` type to `embed.Config.CORS` in `map[string]struct{}` type](https://github.com/coreos/etcd/pull/9490).
-- Remove [`pkg/cors` package](https://github.com/coreos/etcd/pull/9490).
-- Move `"github.com/coreos/etcd/snap"` to [`"github.com/coreos/etcd/raftsnap"`](https://github.com/coreos/etcd/pull/9211).
-- Move `"github.com/coreos/etcd/etcdserver/auth"` to [`"github.com/coreos/etcd/etcdserver/v2auth"`](https://github.com/coreos/etcd/pull/9275).
-- Move `"github.com/coreos/etcd/error"` to [`"github.com/coreos/etcd/etcdserver/v2error"`](https://github.com/coreos/etcd/pull/9274).
-- Move `"github.com/coreos/etcd/store"` to [`"github.com/coreos/etcd/etcdserver/v2store"`](https://github.com/coreos/etcd/pull/9274).
 - Change v3 `etcdctl snapshot` exit codes with [`snapshot` package](https://github.com/coreos/etcd/pull/9118/commits/df689f4280e1cce4b9d61300be13ca604d41670a).
   - Exit on error with exit code 1 (no more exit code 5 or 6 on `snapshot save/restore` commands).
 - Migrate dependency management tool from `glide` to [`golang/dep`](https://github.com/coreos/etcd/pull/9155).
@@ -69,14 +64,25 @@ See [code changes](https://github.com/coreos/etcd/compare/v3.3.0...v3.4.0) and [
   - Now `go get/install/build` on `etcd` packages (e.g. `clientv3`, `tools/benchmark`) enforce builds with etcd `vendor` directory.
 - Replace [gRPC gateway](https://github.com/grpc-ecosystem/grpc-gateway) endpoint `/v3beta` with [`/v3`](https://github.com/coreos/etcd/pull/9298).
   - Deprecated [`/v3alpha`](https://github.com/coreos/etcd/pull/9298).
-- Remove [`embed.Config.SetupLogging`](TODO).
-  - Now logger is set up automatically based on given [`embed.Config.Logger`, `embed.Config.LogOutput`, `embed.Config.Debug` fields](TODO).
+- Change [`wal` package function signatures](https://github.com/coreos/etcd/pull/9572) to support [structured logger and logging to file](https://github.com/coreos/etcd/issues/9438) in server-side.
+  - Previously, `Open(dirpath string, snap walpb.Snapshot) (*WAL, error)`, now `Open(lg *zap.Logger, dirpath string, snap walpb.Snapshot) (*WAL, error)`.
+  - Previously, `OpenForRead(dirpath string, snap walpb.Snapshot) (*WAL, error)`, now `OpenForRead(lg *zap.Logger, dirpath string, snap walpb.Snapshot) (*WAL, error)`.
+  - Previously, `Repair(dirpath string) bool` now `Repair(lg *zap.Logger, dirpath string) bool`.
+  - Previously, `Create(dirpath string, metadata []byte) (*WAL, error)`, now `Create(lg *zap.Logger, dirpath string, metadata []byte) (*WAL, error)`.
+- Remove [`embed.Config.SetupLogging`](https://github.com/coreos/etcd/pull/9572).
+  - Now logger is set up automatically based on [`embed.Config.Logger`, `embed.Config.LogOutput`, `embed.Config.Debug` fields](https://github.com/coreos/etcd/pull/9572).
+- Remove [`pkg/cors` package](https://github.com/coreos/etcd/pull/9490).
+- Move `"github.com/coreos/etcd/snap"` to [`"github.com/coreos/etcd/raftsnap"`](https://github.com/coreos/etcd/pull/9211).
+- Move `"github.com/coreos/etcd/etcdserver/auth"` to [`"github.com/coreos/etcd/etcdserver/v2auth"`](https://github.com/coreos/etcd/pull/9275).
+- Move `"github.com/coreos/etcd/error"` to [`"github.com/coreos/etcd/etcdserver/v2error"`](https://github.com/coreos/etcd/pull/9274).
+- Move `"github.com/coreos/etcd/store"` to [`"github.com/coreos/etcd/etcdserver/v2store"`](https://github.com/coreos/etcd/pull/9274).
 
 ### Dependency
 
 - Upgrade [`google.golang.org/grpc`](https://github.com/grpc/grpc-go/releases) from [**`v1.7.5`**](https://github.com/grpc/grpc-go/releases/tag/v1.7.5) to [**`v1.11.1`**](TODO).
 - Upgrade [`github.com/ugorji/go/codec`](https://github.com/ugorji/go) to [**`v1.1.1`**](https://github.com/ugorji/go/releases/tag/v1.1.1), and [regenerate v2 `client`](https://github.com/coreos/etcd/pull/9494).
 - Upgrade [`github.com/soheilhy/cmux`](https://github.com/soheilhy/cmux/releases) from [**`v0.1.3`**](https://github.com/soheilhy/cmux/releases/tag/v0.1.3) to [**`v0.1.4`**](https://github.com/soheilhy/cmux/releases/tag/v0.1.4).
+- Upgrade [`github.com/google/btree`](https://github.com/google/btree/releases) from [**`google/btree@925471ac9`**](https://github.com/google/btree/commit/925471ac9e2131377a91e1595defec898166fe49) to [**`google/btree@e89373fe6`**](https://github.com/google/btree/commit/e89373fe6b4a7413d7acd6da1725b83ef713e6e4).
 - Upgrade [`github.com/spf13/cobra`](https://github.com/spf13/cobra/releases) from [**`spf13/cobra@1c44ec8d3`**](https://github.com/spf13/cobra/commit/1c44ec8d3f1552cac48999f9306da23c4d8a288b) to [**`spf13/cobra@cd30c2a7e`**](https://github.com/spf13/cobra/commit/cd30c2a7e91a1d63fd9a0027accf18a681e9d50b).
 - Upgrade [`github.com/spf13/pflag`](https://github.com/spf13/pflag/releases) from [**`v1.0.0`**](https://github.com/spf13/pflag/releases/tag/v1.0.0) to [**`spf13/pflag@1ce0cc6db`**](https://github.com/spf13/pflag/commit/1ce0cc6db4029d97571db82f85092fccedb572ce).
 
@@ -131,8 +137,9 @@ See [security doc](https://github.com/coreos/etcd/blob/master/Documentation/op-g
   - If `--discovery-srv-name="foo"`, then query `_etcd-server-ssl-foo._tcp.[YOUR_HOST]` and `_etcd-server-foo._tcp.[YOUR_HOST]`.
   - Useful for operating multiple etcd clusters under the same domain.
 - Support [`etcd --cors`](https://github.com/coreos/etcd/pull/9490) in v3 HTTP requests (gRPC gateway).
-- Add [`--logger`](TODO) flag to support [structured logger and logging to file](TODO) in server-side.
+- Add [`--logger`](https://github.com/coreos/etcd/pull/9572) flag to support [structured logger and logging to file](https://github.com/coreos/etcd/issues/9438) in server-side.
   - e.g. `--logger=capnslog --log-output=default` is the default setting and same as previous etcd server logging format.
+  - TODO: `--logger=zap` is experimental, and journald logging may not work when etcd runs as PID 1.
   - e.g. `--logger=zap --log-output=/tmp/test.log` will log server operations with [JSON-encoded format](TODO) and writes logs to the specified file `/tmp/test.log`.
   - e.g. `--logger=zap --log-output=default` will log server operations with [JSON-encoded format](TODO) and writes logs to `os.Stderr` (detect systemd journald TODO).
   - e.g. `--logger=zap --log-output=stderr` will log server operations with [JSON-encoded format](TODO) and writes logs to `os.Stderr` (bypass journald TODO).