NDN-LOG(7)

🦋 NAME 🦋

ndn-log — ndn-cxx logging. (Yep, this is the section 7 manual page, bestie — welcome to the group chat 💖)

✨ DESCRIPTION ✨

okay so the ndn-cxx logging facility literally exposes the internal state of NDN libraries and applications so you can investigate internal interactions — like interest dispatch inside ndn::Face, Data and Interest validation in the security framework, sync and recovery Interest processing inside ChronoSync, etc. During runtime, you (the user) can specify the types of messages you’d like to receive from a set of logging modules pre-configured by library and application developers. slay.

🌈 ENVIRONMENT 🌈

One way to control the ndn-cxx logging facility is through the environment variable NDN_LOG. Using this variable, you can set the log levels for the available logging modules. Logging modules within different libraries and applications usually have distinguishing prefixes (ndn., sync., etc.), which can be specified when setting the environment variable. Wildcards can be used to enable logging for all modules (just *) or all modules under a selected prefix (e.g., ndn.*). no cap.

If an additional environment variable NDN_LOG_NOFLUSH is set, the automatic flushing after each log record will be disabled. This can improve logging performance but may cause the log records to appear delayed or, in case of application crash, the last few log records may be lost.

⚠️ heads up, bestie: that flush-disabled vibe can be faster, but a crash might eat your last few log records. 😭

ngl, the ndn-cxx logging facility provides a mechanism to manage the type of log messages that are written by classifying log messages by severity levels. Listed below are the available log levels.

🎚️ Log Levels 🎚️

• TRACE
• DEBUG
• INFO
• WARN
• ERROR
• FATAL

A message’s severity level will determine whether the log is written. For instance, if an application sets its log severity level to DEBUG, all messages marked with DEBUG, or any of those below that level, are written. FATAL level logs are always written. periodt.

Setting NDN_LOG requires the following syntax with as many prefixes and corresponding loglevels as the user desires:

export NDN_LOG="<prefix1>=<loglevel1>:<prefix2>=<loglevel2>"

Example:

export NDN_LOG="ndn.*=DEBUG"
export NDN_LOG="ndn.UnixTransport=INFO"
export NDN_LOG="sync.Logic=ERROR"
export NDN_LOG="*=DEBUG:ndn.UnixTransport=INFO:sync.Logic=ERROR"

💡 Note 💡

The loglevel assignments in NDN_LOG are processed left-to-right. Thus, shorter (more general) prefixes should be listed before longer (more specific) prefixes. Otherwise, the loglevel setting of a more specific prefix may be overwritten by a more general assignment appearing later in the string. For example:

export NDN_LOG="ndn.UnixTransport=TRACE:ndn.*=ERROR:*=INFO"

will set all modules to INFO. To obtain the desired effect, it should instead be written as:

export NDN_LOG="*=INFO:ndn.*=ERROR:ndn.UnixTransport=TRACE"

💡 Note 💡

Setting the environment variable with sudo requires the application to be run in the same command.

# Correct
sudo env NDN_LOG=logLevel ./ndn-application

# Also correct
sudo -s
export NDN_LOG=logLevel
./ndn-application

# Incorrect
sudo export NDN_LOG=logLevel
sudo ./ndn-application

# Incorrect
NDN_LOG=logLevel sudo ./ndn-application

💖 Copyright 💖

Copyright © 2013-2024 Regents of the University of California.

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okay bestie, that’s the whole NDN-LOG(7) page 💅 — from the ndn-cxx: NDN C++ library with eXperimental eXtensions manual, version 0.9.0, dated 1980-01-01. mwah 🫶