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Show HN: A tool for complete WebSocket traffic control
9 months ago
- Debug, test, and monitor WebSocket connections in applications.
- Preview of the extension interface and key features in Chrome DevTools.
- Complete WebSocket debugging interface with monitoring panel, message control, live connection tracking, and real-time message traffic display.
- Advanced message simulation with JSON editor, syntax highlighting, and nested parse & fill options.
- Message blocking functionality with real-time interception and BLOCK indicators.
- Save and manage message templates with a favorites system for quick access.
- Handle complex scenarios with multiple connection management, message history, and status tracking.
- Quick installation process: search 'WebSocket DevTools' in Chrome Web Store, add to Chrome, and open in DevTools.
Show HN: TraceRoot – Open-source agentic debugging for distributed services
9 months ago
- TraceRoot is an open-source debugging platform that combines structured traces, logs, and source code with AI-powered analysis.
- It enables multi-agent systems to evolve by interacting with environments and provides real-time tracing and logging.
- The platform supports structured logging and tracing to improve AI agent performance.
- Integrates with tools like GitHub and Notion for a seamless debugging experience.
- Offers a Cursor-like interface specialized for debugging and tracing.
- Community-driven with engineers and researchers focused on advancing multi-agent systems for debugging.
- Provides a free 7-day trial for TraceRoot Cloud with storage and AI agent features.
- Installation involves cloning the GitHub repo, setting up a virtual environment, and running local or Docker setups.
- Requires Jaeger docker container for storing and capturing traces and logs.
- SDK integration involves configuration via a YAML file and setup with GitHub and OpenAI API keys.
Debugging AMD-Specific Issues with Driver Experiments Tool
9 months ago
- Introduction to Radeon Developer Tool Suite and Driver Experiments for debugging AMD-specific issues.
- Driver Experiments tool provides low-level driver behavior toggles, useful in development/testing environments.
- Two highlighted experiments: 'Force NonUniformResourceIndex' and 'Disable color texture compression'.
- NonUniformResourceIndex issue in shaders can cause visual glitches on AMD GPUs if not properly annotated.
- Internal texture compression in GPUs can lead to bugs if barriers or clears are missing or incorrect.
- Driver Experiments can help identify missing NonUniformResourceIndex annotations or texture compression issues.
- Examples of issues resolved by Driver Experiments include visual artifacts from incorrect shader indexing or texture compression.
Zig-Error-Patterns
9 months ago
- Introduction to using print-based debugging and debugger in Zig unit tests.
- Use of 'errdefer' to print debug information only when a test fails, avoiding output clutter.
- Challenges with running tests in the debugger due to binary locations and error handling.
- Combining 'errdefer' with '@breakpoint()' to break on errors during debugging.
- Use of conditional compilation to enable debugger breakpoints based on build options.
- Modification of 'build.zig' to include a 'debugger' flag for conditional breakpoints.
- Automation of debugger execution when the 'debugger' flag is enabled.
- Final setup allows running tests in the debugger with automatic breaks on errors.
Debugging a mysterious HTTP streaming issue
9 months ago
- Encountered HTTP response streaming issues with AI SDK and Node stream API
- Streaming worked with cURL and Postman but failed with node-fetch and browser fetch
- Initial hypothesis was HTTP/2 compliance issues with web streams vs Node streams
- Discovered a temporary fix using a Cloudflare worker as middleware
- Ruled out HTTP version differences as the root cause
- Suspected header stripping ('Transfer-Encoding', 'Connection', 'Content-Encoding') as the issue
- Learned about dynamic responses and HTTP streaming mechanics
- Breakthrough came from noticing cURL's lack of 'Accept-Encoding' header by default
- Identified compression as the root cause and disabled it in Cloudflare
- Realized this was a recurring issue previously encountered at Trieve
- Highlighted Cloudflare's unpredictable behavior with silent configuration changes
- Lessons: compression breaks streaming, cURL vs fetch differences, Cloudflare workers as debugging tools, importance of source availability, and team knowledge sharing
A subtle bug with Go's errgroup
9 months ago
- The author encountered a bug while working on Kratos, which was caught by a test before merging.
- The issue was minimized into a 100-line standalone program for password validation.
- Passwords are stored as hashes to prevent brute-force attacks, with performance optimizations using errgroup for concurrent tasks.
- A bug was found where the context was canceled prematurely, preventing a password leak check from running.
- Two fixes were proposed: running the HTTP check within the errgroup or avoiding context shadowing.
- The author emphasizes the importance of reading API documentation thoroughly and understanding the fine print.
- The blog post is open-source and encourages contributions or support from readers.
How to interactively debug GitHub Actions with netcat
9 months ago
- Introduction to using tmate for interactive debugging in GitHub Actions workflows.
- Original method involved setting up reverse shells with netcat and ngrok for debugging.
- Explanation of reverse shells: connecting out to a remote machine to forward a shell.
- Steps to catch a shell using netcat and forward ports with ngrok.
- Configuring GitHub Actions to throw a reverse shell using secrets for host and port.
- Demonstration of interactive shell usage on GitHub Actions runner for debugging.
- Limitations mentioned, such as issues with control commands and pseudo-TTY requirements.
- Example commands run in the shell to explore the runner's system and debug CI steps.
You Should Add Debug Views to Your DB
9 months ago
- Bug report details Sophie's error when viewing a diff in her contribution to the @unison/cloud project.
- The process of finding the specific contribution involves complex SQL queries with multiple joins.
- Creating a debugging view (debug_contributions) simplifies future queries by pre-defining joins and including readable fields like branch names and project shorthand.
- Debugging views are efficient, don't consume extra database space, and can be easily updated or deleted.
- The article suggests using debugging views to save time on repetitive queries, despite potential performance trade-offs with computed columns.
- The author promotes their book on optics in Haskell and functional programming, linking it to the educational value of the post.
Vibe Debugging: Enterprises' Up and Coming Nightmare
8 months ago
- The author struggles with debugging a meme stock valuation site, facing erratic growth numbers and messy code.
- Attempts to fix the code with AI assistance (Claude Code) lead to distractions and partial fixes, ultimately resulting in the removal of a feature.
- Vibe debugging is criticized, with suggestions to provide full specifications, allow agent questions, and review changes thoroughly.
- AI-assisted coding is seen as both productive and overhyped, with concerns about code quality and security.
- Enterprises are rapidly adopting AI coding tools, leading to an explosion in code volume and potential bugs.
- The need for robust monitoring and logging is emphasized to handle AI-generated code in production.
- CI/CD pipelines must evolve to include more rigorous testing and quality gates to manage AI-generated code.
- The author predicts growth in B2B SaaS spending on monitoring and DevOps tools, as well as a wave of AI-native startups.
- AI progress is seen as non-linear, with plateaus between breakthroughs, requiring current systems to be built for today's AI capabilities.
- The enterprise AI wave is fundamentally reshaping software development practices, demanding new safeguards and oversight.
Bash Strict Mode
8 months ago
- Bash strict mode makes scripts more robust, reliable, and maintainable by causing them to fail immediately on errors.
- Key components of bash strict mode include `set -euo pipefail` and `IFS=$'\n\t'`.
- `set -e` causes the script to exit immediately if any command fails.
- `set -u` treats references to undefined variables as errors.
- `set -o pipefail` ensures that pipeline failures are not masked by the success of later commands.
- Setting `IFS` to `$'\n\t'` improves word splitting behavior in loops and arrays.
- Common issues and solutions when using strict mode include handling sourced documents, positional parameters, and commands expected to fail.
- Essential clean-up can be managed using bash exit traps.
- Short-circuiting expressions can lead to unexpected exit codes, especially when they are the last line of a script.
OOMProf: Profiling on the Brink
8 months ago
- Introduction to the Linux OOM killer and its challenges in debugging memory issues.
- Development of OOMProf, an eBPF-based monitoring system for profiling Go programs during OOM kills.
- Challenges with OOM kills include lack of context, difficulty in identifying the root cause, and rapid system unraveling.
- Explanation of Linux's overcommit behavior and its implications for memory allocation failures.
- Techniques for diagnosing OOM issues, including heap growth tracing and turning off overcommit.
- Complications in garbage-collected languages like Go, where heap profiles may be outdated.
- Solution using eBPF to profile memory at the moment of OOM kill by leveraging tracepoints.
- Potential issues with eBPF memory reading, instruction limits, and handling large numbers of memory buckets.
- Usage of OOMProf in the Parca Agent for continuous monitoring and automatic profile uploads.
- Future plans include support for other allocators (jemalloc, tcmalloc, mimalloc) and additional diagnostics like stack dumps.
How to Slow Down a Program? and Why It Can Be Useful
8 months ago
- Slowing down programs can help detect race conditions, simulate speedups, and assess profiler accuracy.
- Approaches like CHESS, WAFFLE, and NACD use slowdown to explore different instruction interleavings and schedules.
- The Coz profiler uses slowdown to simulate speedups, helping estimate optimization benefits before implementation.
- Current slowdown methods are coarse-grained, often using Thread.sleep() or pausing execution.
- Fine-grained slowdowns, like inserting NOP or MOV instructions in basic blocks, can improve precision.
- Experiments on an Intel Core i5-10600 show NOP and MOV instructions are effective for controlled slowdown.
- Slowing down basic blocks by inserting NOPs can double execution time while maintaining accurate profiling results.
- The paper evaluates six x86 instruction candidates, finding NOP and MOV most suitable for fine-grained slowdown.
- Future research aims to use fine-grained slowdown for advanced developer tooling.
Reloading Classes in Python
8 months ago
- Sign up for the RSS feed of the crime de-coder blog for consistent updates.
- Recent blog posts include topics on crime monitoring, gun shot detection tech, LLMs for data extraction, and finding outliers in proportions.
- ASEBP conference submissions for 2026 are open, with a talk on planning experiments.
- Use `importlib.reload` to reload Python modules for easier debugging without restarting the entire script.
- For long-running code, save objects with `pickle` to avoid re-running the entire process during debugging.
- A function `intersection_length` is provided to approximate the shared border length between two polygons using small buffers.
- The function is tested with various polygon configurations to ensure accuracy.
- The buffer method helps handle imperfections in real GIS data by smoothing out minor discrepancies.
Why did dlclose not unload the library? (2023)
8 months ago
- dlclose may not unload a library due to several conditions, including reference count > 1, NODELETE flag, or pending thread local storage (TLS) destructors.
- In the debugging scenario, libA (Rust) was unloaded, but libB (C++) was not, due to pending TLS destructors registered by libB.
- The NODELETE flag can be set in the ELF binary or via dlopen flags, and symbols marked as STB_GNU_UNIQUE (common in libstdc++.so) also trigger this flag.
- Enabling logging (env_logger) in libA caused it to register TLS destructors, preventing its unloading and thus keeping libB's state consistent.
- Use LD_DEBUG to debug dynamic loader behavior, though it doesn't show pending TLS destructors—breakpoints in _dlclose are needed for that.
Improving LLM token usage when debugging
8 months ago
- LLM-powered coding assistants process excessive irrelevant log output, increasing API costs and response time.
- Proposed solution: Apparatus.Exec, a CLI tool designed to filter command outputs for LLM-driven development workflows.
- Features include predefined shortcuts, regex filters, working directories, pattern templates, and debug mode.
- Significantly reduces token usage by showing only relevant error messages, improving debugging efficiency.
- Limitations include handling interactive commands and real-time monitoring, where traditional terminals are still needed.
Things you can do with a debugger but not with print debugging
8 months ago
- Debuggers are underutilized due to setup difficulties and remote environment constraints.
- Debug logging is more commonly used than debuggers, despite debuggers offering unique advantages.
- Debuggers allow inspection of the entire call stack and variable states at different frames.
- They enable dynamic evaluation of expressions and modification of program state during runtime.
- Debuggers can catch exceptions at their source, aiding in understanding why exceptions occur.
- They allow altering execution flow without code changes, reducing risks of accidental commits.
- Standardized debug configurations in IDEs like VSCode or IntelliJ streamline project setup for teams.
- Debug configurations can include environment variables, .env files, and CLI arguments for consistency.
- Having debug configurations for every application entry-point accelerates onboarding for new contributors.
The case of the crash on a null pointer even though we checked it for null
8 months ago
- A crash investigation revealed a null pointer dereference in a C++/WinRT projection of a COM call.
- The crash occurred when calling `IVectorView<T>::Size` on a null pointer, indicating the `std::optional` containing the vector was empty.
- The code incorrectly checked for `nullptr` against an `std::optional`, which does not behave as intended for empty optionals.
- The fix involved removing `std::optional` and directly using `IVectorView`, which naturally handles null checks.
- The investigation highlighted the importance of understanding type behaviors, especially with `std::optional` and nullable types.
Harvey Mudd Miniature Machine
8 months ago
- Hmmm is a Python-based assembler and simulator for a custom assembly language.
- The assembly language includes instructions for arithmetic, jumps, memory interaction, and register manipulation.
- Special registers include r0, which always provides zero when read and discards writes.
- Debug mode offers commands like continue, dump, help, print, quit, and run for program inspection.
- Example programs demonstrate division and error handling, including division by zero.
- Error messages highlight syntax, argument, register, and line number issues during assembly.
Uniprof: Universal CPU Profiling
8 months ago
- Uniprof simplifies CPU profiling for humans and AI agents without requiring code changes or added dependencies.
- Supports profiling applications in various languages (e.g., Python, Ruby) with commands like `npx uniprof python app.py`.
- Automatically detects the platform and selects the appropriate profiler (e.g., py-spy for Python).
- Provides detailed profiling results including top functions by time, samples, and location in the code.
- Offers both CLI usage and integration as an MCP server for AI agents to debug performance bottlenecks.
- Includes built-in flamegraph visualization powered by speedscope for easier analysis.
- Example shown where Claude Code uses uniprof to identify and fix a real performance bottleneck in the Context app.
Logfire – OpenTelemetry based tracing SaaS
8 months ago
- Pydantic Logfire provides comprehensive observability for applications and LLMs, built on OpenTelemetry.
- It offers full visibility into application traces, logs, and metrics, including network calls, database queries, and third-party APIs.
- Features include real-time application traces, SQL query capabilities, and integrations with popular libraries.
- Pydantic Logfire supports a seamless transition from local development to production monitoring without tool switching.
- The tool is designed for ease of use with streamlined SDKs for Python, Rust, and Typescript.
- It includes integrated analytics for both technical and business insights, such as exceptions and customer behavior.
- Pydantic Logfire integrates with a wide range of tools and frameworks, enhancing observability across different stacks.

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#debugging

Show HN: A tool for complete WebSocket traffic control

Show HN: TraceRoot – Open-source agentic debugging for distributed services

Debugging AMD-Specific Issues with Driver Experiments Tool

Zig-Error-Patterns

Debugging a mysterious HTTP streaming issue

A subtle bug with Go's errgroup

How to interactively debug GitHub Actions with netcat

You Should Add Debug Views to Your DB

Vibe Debugging: Enterprises' Up and Coming Nightmare

Bash Strict Mode

OOMProf: Profiling on the Brink

How to Slow Down a Program? and Why It Can Be Useful

Reloading Classes in Python

Why did dlclose not unload the library? (2023)

Improving LLM token usage when debugging

Things you can do with a debugger but not with print debugging

The case of the crash on a null pointer even though we checked it for null

Harvey Mudd Miniature Machine

Uniprof: Universal CPU Profiling

Logfire – OpenTelemetry based tracing SaaS