laskoviymishka commented on code in PR #1430:
URL: https://github.com/apache/iceberg-go/pull/1430#discussion_r3570272993
##########
table/table.go:
##########
@@ -157,6 +168,13 @@ func (t *Table) Refresh(ctx context.Context) error {
t.fsF = fresh.fsF
t.metadataLocation = fresh.metadataLocation
t.planner = fresh.planner
+ // Only inherit the catalog-derived reporter when the caller hasn't set
one
+ // of their own. Refresh runs inside commit retry loops, so
unconditionally
+ // copying fresh.reporter would silently revert a
WithMetricsReporter-injected
+ // reporter to the catalog default mid-operation.
+ if _, isNop := t.reporter.(metrics.NopReporter); isNop {
Review Comment:
This is the one thing I'd tighten before approving. The guard uses the
concrete `NopReporter` type as a stand-in for "the caller never set a
reporter," and that conflates two different intents.
A caller who explicitly opts out with
`WithMetricsReporter(metrics.NopReporter{})` — or passes `metrics.Combine(nil,
nil)`, which resolves to `NopReporter{}` — reads as "unset" here and gets
silently reverted to the catalog default on the next `Refresh`. Since this is
the exact invariant last round was about, I'd rather make it explicit with a
was-set flag:
```go
// in WithMetricsReporter, when r != nil:
t.reporter = r
t.reporterSet = true
// in Refresh:
if !t.reporterSet {
t.reporter = fresh.reporter
}
```
That also drops the type dependency entirely. And I'd add the companion test
— `WithMetricsReporter(metrics.NopReporter{})`, refresh against a catalog that
hands back a logging reporter, assert the reporter is still `NopReporter{}`.
Right now that case would silently fail. wdyt?
##########
table/table.go:
##########
@@ -873,28 +905,48 @@ func (t Table) Scan(opts ...ScanOption) *Scan {
return s
}
+// Option configures a [Table] at construction. Options are applied in order
+// after the core fields are set.
+type Option func(*Table)
+
+// WithMetricsReporter sets the metrics reporter for the table; scans created
+// from the table inherit it. A nil reporter is ignored (the table keeps its
+// default no-op reporter).
+func WithMetricsReporter(r metrics.Reporter) Option {
+ return func(t *Table) {
Review Comment:
`WithReporter` returns the package-level `noopOption` when `r` is nil, but
this allocates a live closure that no-ops on nil. Could mirror `WithReporter`
with a shared `noopTableOption` so the two idioms match. Non-blocking.
##########
metrics/registry.go:
##########
@@ -0,0 +1,99 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package metrics
+
+import (
+ "fmt"
+ "sync"
+)
+
+// ReporterImplKey is the catalog/table property that selects a registered
+// reporter by name (e.g. "logging"). It is the Go analogue of Java's
+// metrics-reporter-impl; Go uses a name→factory registry rather than
+// reflection over a class name.
+const ReporterImplKey = "metrics-reporter-impl"
+
+// Built-in reporter names usable as the value of [ReporterImplKey].
+const (
+ ReporterNameNop = "nop"
+ ReporterNameLogging = "logging"
+)
+
+// Factory builds a Reporter from configuration properties. The same property
+// map that selected the reporter is passed in, so a factory may read its own
+// configuration keys.
+type Factory func(props map[string]string) (Reporter, error)
+
+var (
+ registryMu sync.RWMutex
+ registry = map[string]Factory{}
+)
+
+func init() {
+ Register(ReporterNameNop, func(map[string]string) (Reporter, error) {
return NopReporter{}, nil })
+ Register(ReporterNameLogging, func(map[string]string) (Reporter, error)
{
+ return NewLoggingReporter(nil), nil
+ })
+}
+
+// Register makes a reporter factory available under name. It panics if name is
+// empty or already registered, mirroring database/sql.Register — registration
+// is expected to happen once, from package init.
+func Register(name string, factory Factory) {
+ if name == "" {
+ panic("metrics: Register called with empty name")
+ }
+ if factory == nil {
+ panic("metrics: Register called with nil factory")
+ }
+ registryMu.Lock()
+ defer registryMu.Unlock()
+ if _, dup := registry[name]; dup {
+ panic("metrics: Register called twice for " + name)
+ }
+ registry[name] = factory
+}
+
+// Deregister removes a previously registered reporter factory. It is a no-op
if
+// name is not registered. This exists primarily so tests can register a
factory
+// and undo it via t.Cleanup, keeping the process-global registry re-runnable
+// under go test -count=N.
+func Deregister(name string) {
+ registryMu.Lock()
+ defer registryMu.Unlock()
+ delete(registry, name)
+}
+
+// FromProperties builds the reporter named by props[ReporterImplKey]. An
absent
+// or empty name yields [NopReporter] (reporting is opt-in), and an
unrecognized name is
Review Comment:
The "reporting is opt-in" choice is reasonable, but it diverges from Java,
where an absent `metrics-reporter-impl` defaults to `LoggingMetricsReporter`,
not a nop. Folks migrating from Java will expect scan/commit reports to show up
by default, so I'd add a line to this godoc noting the divergence is
intentional. Non-blocking.
##########
catalog/hive/hive.go:
##########
@@ -226,12 +233,18 @@ func (c *Catalog) RegisterTable(ctx context.Context,
identifier table.Identifier
return nil, fmt.Errorf("%w: %s.%s",
catalog.ErrTableAlreadyExists, database, tableName)
}
+ reporter, err := metrics.FromProperties(c.opts.props)
+ if err != nil {
+ return nil, fmt.Errorf("failed to initialize metrics reporter:
%w", err)
+ }
+
tbl, err := table.NewFromLocation(
ctx,
identifier,
metadataLocation,
io.LoadFSFunc(c.opts.props, metadataLocation),
c,
+ table.WithMetricsReporter(reporter),
)
if err != nil {
return nil, fmt.Errorf("failed to read table metadata from %s:
%s", metadataLocation, err)
Review Comment:
Not from this PR, but it's now sitting right under the new reporter block
and the reporter error just above it uses `%w`. I'd switch this `%s` to `%w` so
`errors.Is`/`errors.As` can unwrap it. Non-blocking.
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