C++ Log Manager

Introduction

In professional software, rather than outputting messages to the standard output stream for the purpose of debugging or indicating errors, developers will typically use log files to hide such information from end-users. Log files are usually quite massive in size and there are often many log entries that may be irrelevant to what the developer is trying to examine. The developer needs to have the ability to quickly search for and analyze only the entries they care about. This project is designed to helps with this task, by creating an interactive manager to search, parse, and edit log files.

Table of Contents

• Getting Started
• Executable
• Input Format
• Commands List
• Conclusion

Getting Started

Compile all files with make all

Run on an example log with logman example-log.txt

This project also supports input and output redirection.
Run with logman example-log.txt < example-cmds.txt > example-output.txt

Executable

Makefile builds an executable program called logman. The program will begin by reading an input file containing log entries, and then will enter an interactive mode where the user can perform timestamp, category, and keyword searches for the purpose of constructing an “excerpt list” of the log file. logman also allows the user to manage and display this “excerpt list” to identify the important/relevant entries of their log file.

Input Format

On startup, logman reads a series of log entries from the master log file, a file specified via the command line. The file is a plain text file which describes a single log entry on every line. Each log entry consists of three fields separated by vertical bar (|) characters. The first field contains the timestamp of the log entry, the second contains the category of the log entry, and the third contains the message of the log entry. The following is a description of the formats of each field:

• Log timestamps will be given in the format mmhhss , where the various components (month, day, hour, minute, second) between colons are given as a pair of digits.

• Log categories will be given as strings and correspond to some general, but meaningful, description of which part of the logged program outputted the message.

• Log messages will be given as strings.

An example of two lines from the master log file:

10:09:03:45:50|TCP|Packet 0x4235124 sent
09:15:12:00:00|Clock|Noon 09/15

Commands List

Search Commands:

• t - timestamp search
  % t <timestamp1>|<timestamp2>
  Executes a search for all log entries with timestamps that fall within a specified time range and displays the number of matching entries.
• m - matching search
  % m <timestamp>
  Searches for all log entries with timestamps matching the given timestamp and displays the number of matching entries.
• c - category search
  % c <string>
  Searches for all log entries with categories matching and displays the number of matching entries.
• k - keyword search
  % k <string>
  Perform a keyword search on the log categories and log messages, and display the number of matching entries.

Excerpt List Commands:

• a - append log entry (by entryID)
  % a <integer>
  Append the log entry from position in the master log file onto the end of the excerpt list.
• r - append search results
  % r
  Add all log entries returned by the most recent previous search (commands t , m , c , or k ) to the end of the excerpt list.
• d - delete log entry (by excerpt list number)
  % d <integer>
  Remove the excerpt list entry at position .
• b - move to beginning (by excerpt list number)
  % b <integer>
  Move the excerpt list entry at position < integer> to the beginning of the excerpt list.
• e - move to end (by excerpt list number)
  % e <integer>
  Move the excerpt list entry at position < integer> to the end of the excerpt list.
• s - sort excerpt list (by timestamp)
  % s
  Sort each entry in the excerpt list by timestamp, with ties broken by category, and further ties broken by entryID.
• l - clear excerpt list
  % l
  Remove all entries from the excerpt list.

Output Commands:

• g - print most recent search results
  % g
  Log entries are printed one log entry per line, sorted by timestamp, with ties broken by category, and further ties broken by entryID. Each output line should be printed as follows:
  <entryID>|<timestamp>|<category>|<message><newline>
• p - print excerpt list
  % p
  Excerpt list entries are printed one entry per line in the order they appear in the excerpt list.

Miscellaneous Commands:

• q - quit
  % q
  Terminate the program with non-error status.
• # - no operation
  % # <string>
  useful for adding comments to command files
• h - help
  % h

Conclusion

This project helped me gain experience writing code that makes use of multiple interacting data structures. The design portion of this project was significant; spending plenty of time thinking about what data structures to use and how they will interact.

I’ve gained valuable experience selecting appropriate data structures for a given problem, as well as how to use various abstract data types.