Alerting Utilities in Go

A small Go package for practicing debugging with realistic alert-processing helpers. It covers four common tasks: deduplicating alerts, assigning severity from an error rate, retrying transient failures, and parsing structured log lines.

The repository contains the corrected implementation and a test suite that documents its expected behavior. A summary of the original bugs and their fixes is available in DEBUG_REPORT_001.md. Go back in commit history to see the original bugs and their fixes.

Requirements

• Go 1.22.2 or later

No third-party dependencies are required.

Run the tests

From the repository root:

go test -v ./...

Package overview

Deduplicate alerts

DedupeAlerts removes repeated alert IDs within a single batch while preserving the first occurrence and its input order. Each call starts with a fresh deduplication scope.

alerts := []alerting.Alert{
	{ID: "db-1", Message: "database unavailable"},
	{ID: "db-1", Message: "database unavailable"},
	{ID: "api-1", Message: "high latency"},
}

unique := alerting.DedupeAlerts(alerts) // two alerts

Compute severity

ComputeSeverity maps an error rate to a label using these boundaries:

Error rate	Severity
< 0.05	low
0.05 to < 0.15	medium
0.15 to < 0.30	high
>= 0.30	critical

Retry an operation

RetryWithBackoff calls a function up to the requested number of attempts. The delay starts at baseDelay and doubles after each failed attempt. It returns immediately on success or returns the last error when all attempts fail.

err := alerting.RetryWithBackoff(func() error {
	return sendAlert()
}, 3, 100*time.Millisecond)

Parse a log line

ParseLogLine converts a whitespace-delimited line into a LogEvent:

2024-01-15T10:30:00Z ERROR story-view-api database connection timeout

The first three fields become the timestamp, level, and service. Everything after them becomes the message, so multi-word messages are preserved. Lines with fewer than four fields return an error.

Project layout

.
├── alerting.go          # Package implementation
├── alerting_test.go     # Behavioral tests
├── DEBUG_REPORT_001.md  # Original bug report and fixes
└── go.mod