tanmayrauth commented on code in PR #1343: URL: https://github.com/apache/iceberg-go/pull/1343#discussion_r3501079368
########## metrics/reporters_test.go: ########## @@ -0,0 +1,143 @@ +// 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 ( + "context" + "sync" + "testing" + + "github.com/stretchr/testify/assert" + "github.com/stretchr/testify/require" +) + +// testReport is a minimal MetricsReport. The marker is unexported (sealed to +// this package), so report values can only be created from within the +// package — this white-box test is how we exercise the reporters until the +// concrete report types land. +type testReport struct{ name string } + +func (testReport) isMetricsReport() {} + +// countingReporter records how many reports it received. +type countingReporter struct { + mu sync.Mutex + count int +} + +func (c *countingReporter) Report(context.Context, MetricsReport) { + c.mu.Lock() + defer c.mu.Unlock() + c.count++ +} + +func (c *countingReporter) calls() int { + c.mu.Lock() + defer c.mu.Unlock() + + return c.count +} + +// panickingReporter always panics, to verify Combine isolates failures. +type panickingReporter struct{} + +func (panickingReporter) Report(context.Context, MetricsReport) { panic("boom") } + +func TestNopReporter(t *testing.T) { + // NopReporter must accept anything, including nil, without panicking. + assert.NotPanics(t, func() { + NopReporter{}.Report(context.Background(), nil) + NopReporter{}.Report(context.Background(), testReport{}) + }) +} + +func TestInMemoryReporter(t *testing.T) { + var r InMemoryReporter + require.Empty(t, r.Reports()) + + r.Report(context.Background(), nil) // ignored + require.Empty(t, r.Reports()) + + r.Report(context.Background(), testReport{name: "a"}) + r.Report(context.Background(), testReport{name: "b"}) + + got := r.Reports() + require.Len(t, got, 2) + assert.Equal(t, testReport{name: "a"}, got[0]) + assert.Equal(t, testReport{name: "b"}, got[1]) + + // Reports returns a copy: mutating it must not affect the reporter. + got[0] = nil + require.Len(t, r.Reports(), 2) + + r.Reset() + require.Empty(t, r.Reports()) +} + +func TestLoggingReporterNilLoggerAndReport(t *testing.T) { + r := NewLoggingReporter(nil) // must fall back to slog.Default + require.NotNil(t, r) + assert.NotPanics(t, func() { + r.Report(context.Background(), nil) + r.Report(context.Background(), testReport{name: "x"}) + }) +} + +func TestCombine(t *testing.T) { + t.Run("no reporters returns Nop", func(t *testing.T) { + assert.IsType(t, NopReporter{}, Combine()) + assert.IsType(t, NopReporter{}, Combine(nil, nil)) + }) + + t.Run("single reporter returned directly", func(t *testing.T) { + c := &countingReporter{} + assert.Same(t, c, Combine(c)) + assert.Same(t, c, Combine(nil, c, nil)) + }) + + t.Run("fans out to all", func(t *testing.T) { + a, b := &countingReporter{}, &countingReporter{} + Combine(a, b).Report(context.Background(), testReport{}) + assert.Equal(t, 1, a.calls()) + assert.Equal(t, 1, b.calls()) + }) + + t.Run("isolates a panicking reporter", func(t *testing.T) { + after := &countingReporter{} + r := Combine(panickingReporter{}, after) + assert.NotPanics(t, func() { + r.Report(context.Background(), testReport{}) + }) + assert.Equal(t, 1, after.calls(), "reporters after a panic still run") + }) +} + +func TestInMemoryReporterConcurrent(t *testing.T) { Review Comment: Both done. Extended test-race in the Makefile to include ./metrics/..., and the test now runs a foreground goroutine looping on Reports() while the 100 writers run, so -race actually exercises the read-under-write path instead of just confirming the goroutines finish. Verified locally with go test -race ./metrics/.... ########## metrics/reporters_test.go: ########## @@ -0,0 +1,143 @@ +// 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 ( + "context" + "sync" + "testing" + + "github.com/stretchr/testify/assert" + "github.com/stretchr/testify/require" +) + +// testReport is a minimal MetricsReport. The marker is unexported (sealed to +// this package), so report values can only be created from within the +// package — this white-box test is how we exercise the reporters until the +// concrete report types land. +type testReport struct{ name string } + +func (testReport) isMetricsReport() {} + +// countingReporter records how many reports it received. +type countingReporter struct { + mu sync.Mutex + count int +} + +func (c *countingReporter) Report(context.Context, MetricsReport) { + c.mu.Lock() + defer c.mu.Unlock() + c.count++ +} + +func (c *countingReporter) calls() int { + c.mu.Lock() + defer c.mu.Unlock() + + return c.count +} + +// panickingReporter always panics, to verify Combine isolates failures. +type panickingReporter struct{} + +func (panickingReporter) Report(context.Context, MetricsReport) { panic("boom") } + +func TestNopReporter(t *testing.T) { + // NopReporter must accept anything, including nil, without panicking. + assert.NotPanics(t, func() { + NopReporter{}.Report(context.Background(), nil) + NopReporter{}.Report(context.Background(), testReport{}) + }) +} + +func TestInMemoryReporter(t *testing.T) { + var r InMemoryReporter + require.Empty(t, r.Reports()) + + r.Report(context.Background(), nil) // ignored + require.Empty(t, r.Reports()) + + r.Report(context.Background(), testReport{name: "a"}) + r.Report(context.Background(), testReport{name: "b"}) + + got := r.Reports() + require.Len(t, got, 2) + assert.Equal(t, testReport{name: "a"}, got[0]) + assert.Equal(t, testReport{name: "b"}, got[1]) + + // Reports returns a copy: mutating it must not affect the reporter. + got[0] = nil + require.Len(t, r.Reports(), 2) + + r.Reset() + require.Empty(t, r.Reports()) +} + +func TestLoggingReporterNilLoggerAndReport(t *testing.T) { + r := NewLoggingReporter(nil) // must fall back to slog.Default + require.NotNil(t, r) + assert.NotPanics(t, func() { Review Comment: Splitted into two subtests: the nil-logger fallback keeps the NotPanics check, and a new subtest wires a slog.NewTextHandler over a bytes.Buffer and asserts the output contains level=INFO, iceberg metrics report, and the report value — and that a nil report produces no output. It'll now fail if the log call is deleted, mis-leveled, or drops the report. ########## metrics/reporters.go: ########## @@ -0,0 +1,141 @@ +// 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 ( + "context" + "log/slog" + "sync" +) + +// NopReporter is a [Reporter] that discards every report. It is the default +// when no reporter is configured, so that instrumentation is free unless a user +// opts in. The zero value is ready to use. +type NopReporter struct{} + +var _ Reporter = NopReporter{} + +// Report implements [Reporter] and does nothing. +func (NopReporter) Report(context.Context, MetricsReport) {} + +// LoggingReporter is a [Reporter] that logs each report via an [slog.Logger]. It +// is a convenient default for development and debugging. +type LoggingReporter struct { + logger *slog.Logger +} + +var _ Reporter = (*LoggingReporter)(nil) + +// NewLoggingReporter returns a [LoggingReporter] that logs to logger. If logger +// is nil, [slog.Default] is used. +func NewLoggingReporter(logger *slog.Logger) *LoggingReporter { + if logger == nil { + logger = slog.Default() + } + + return &LoggingReporter{logger: logger} +} + +// Report logs report at info level. +func (r *LoggingReporter) Report(ctx context.Context, report MetricsReport) { + if report == nil { + return + } + r.logger.InfoContext(ctx, "iceberg metrics report", "report", report) +} + +// InMemoryReporter is a [Reporter] that retains every report it receives. It is +// primarily intended for tests and inspection. It is safe for concurrent use. +type InMemoryReporter struct { + mu sync.Mutex + reports []MetricsReport +} + +var _ Reporter = (*InMemoryReporter)(nil) + +// Report appends report to the retained set. +func (r *InMemoryReporter) Report(_ context.Context, report MetricsReport) { + if report == nil { + return + } + r.mu.Lock() + defer r.mu.Unlock() + r.reports = append(r.reports, report) +} + +// Reports returns a copy of the reports received so far, in arrival order. +func (r *InMemoryReporter) Reports() []MetricsReport { + r.mu.Lock() + defer r.mu.Unlock() + + return append([]MetricsReport(nil), r.reports...) +} + +// Reset discards all retained reports. +func (r *InMemoryReporter) Reset() { + r.mu.Lock() + defer r.mu.Unlock() + r.reports = nil +} + +// Combine returns a [Reporter] that forwards each report to all of the given +// reporters in order. nil reporters are skipped. A panic in one reporter must +// not prevent the others from receiving the report, so each call is isolated; +// in keeping with the [Reporter] contract a misbehaving reporter never affects +// the observed operation. A recovered panic is logged at debug level via +// [slog.Default] so a broken reporter is not entirely invisible. +// +// As a convenience, Combine with no reporters returns [NopReporter], and with a +// single non-nil reporter returns that reporter directly. The per-reporter +// panic recovery therefore applies only when two or more reporters are +// combined: a lone reporter is returned unwrapped and runs exactly as it would +// if called directly, without the safety net. +func Combine(reporters ...Reporter) Reporter { + nonNil := make([]Reporter, 0, len(reporters)) + for _, r := range reporters { + if r != nil { + nonNil = append(nonNil, r) + } + } + + switch len(nonNil) { Review Comment: Agreed, went with always-wrap. Dropped the case 1 fast path entirely — Combine now returns NopReporter{} for zero non-nil reporters and a *compositeReporter otherwise, so even a lone reporter gets the isolation we advertise and (*LoggingReporter)(nil) can no longer escape unwrapped to nil-deref later. The one extra range over a single-element slice is well worth closing the bug class. Added a test that drives a typed-nil pointer through Combine and asserts it doesn't panic. ########## metrics/reporters.go: ########## @@ -0,0 +1,141 @@ +// 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 ( + "context" + "log/slog" + "sync" +) + +// NopReporter is a [Reporter] that discards every report. It is the default +// when no reporter is configured, so that instrumentation is free unless a user +// opts in. The zero value is ready to use. +type NopReporter struct{} + +var _ Reporter = NopReporter{} + +// Report implements [Reporter] and does nothing. +func (NopReporter) Report(context.Context, MetricsReport) {} + +// LoggingReporter is a [Reporter] that logs each report via an [slog.Logger]. It +// is a convenient default for development and debugging. +type LoggingReporter struct { + logger *slog.Logger +} + +var _ Reporter = (*LoggingReporter)(nil) + +// NewLoggingReporter returns a [LoggingReporter] that logs to logger. If logger +// is nil, [slog.Default] is used. +func NewLoggingReporter(logger *slog.Logger) *LoggingReporter { + if logger == nil { + logger = slog.Default() + } + + return &LoggingReporter{logger: logger} +} + +// Report logs report at info level. +func (r *LoggingReporter) Report(ctx context.Context, report MetricsReport) { + if report == nil { + return + } + r.logger.InfoContext(ctx, "iceberg metrics report", "report", report) +} + +// InMemoryReporter is a [Reporter] that retains every report it receives. It is +// primarily intended for tests and inspection. It is safe for concurrent use. +type InMemoryReporter struct { + mu sync.Mutex + reports []MetricsReport +} + +var _ Reporter = (*InMemoryReporter)(nil) + +// Report appends report to the retained set. +func (r *InMemoryReporter) Report(_ context.Context, report MetricsReport) { + if report == nil { + return + } + r.mu.Lock() + defer r.mu.Unlock() + r.reports = append(r.reports, report) +} + +// Reports returns a copy of the reports received so far, in arrival order. +func (r *InMemoryReporter) Reports() []MetricsReport { + r.mu.Lock() + defer r.mu.Unlock() + + return append([]MetricsReport(nil), r.reports...) +} + +// Reset discards all retained reports. +func (r *InMemoryReporter) Reset() { + r.mu.Lock() + defer r.mu.Unlock() + r.reports = nil +} + +// Combine returns a [Reporter] that forwards each report to all of the given +// reporters in order. nil reporters are skipped. A panic in one reporter must +// not prevent the others from receiving the report, so each call is isolated; +// in keeping with the [Reporter] contract a misbehaving reporter never affects +// the observed operation. A recovered panic is logged at debug level via +// [slog.Default] so a broken reporter is not entirely invisible. +// +// As a convenience, Combine with no reporters returns [NopReporter], and with a +// single non-nil reporter returns that reporter directly. The per-reporter +// panic recovery therefore applies only when two or more reporters are +// combined: a lone reporter is returned unwrapped and runs exactly as it would +// if called directly, without the safety net. +func Combine(reporters ...Reporter) Reporter { + nonNil := make([]Reporter, 0, len(reporters)) + for _, r := range reporters { + if r != nil { + nonNil = append(nonNil, r) + } + } + + switch len(nonNil) { + case 0: + return NopReporter{} + case 1: + return nonNil[0] + default: + return compositeReporter(nonNil) + } +} + +type compositeReporter []Reporter + Review Comment: compositeReporter is now a struct carrying an optional *slog.Logger, and the recover logs at Warn with the offending reporter's %T plus the recovered value before continuing — matching the re-surface pattern in schema.go/visitors.go. Still swallowed for propagation, just no longer silent. -- This is an automated message from the Apache Git Service. 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