fake-log-generator

Generates fake logs with configurable statistical characteristics

Configuration

Configuration takes place in config.ts, which exports the configuration object.

Key	Type	Default	Description
format	String	undefined	A format string as used in printf (see std/fmt for details)
fieldSeparator	String	","	The field separator string (if format is undefined)
lineSeparator	String	"\n"	The line separator string (if format is undefined)
lines	Number || NumberConfig	10	The number of lines to generate
fields	Array	undefined	The array of fields

Numeric fields as lines can be given as a number as well as a NumberConfig object:

   {
     min: 0,                  // inclusive
     max: 10,                 // exclusive
     distribution: 'uniform', // or linear, so the max value appears more often
   }

Field definitions

Every field is defined by an object.

Key	Type	Default	Description
type	String	undefined	The type of this field, e.g. integer
name	String	undefined	A name for this field, for future use
config	Object	undefined	The configuration for this field, dependent of the type

Field types

datetime

Generates consecutive timestamps, starting at startDate as configured in the configuration oject.

Key	Type	Default	Description
startDate	String	"2020-01-01"	A parseable date to start from
step	Number || NumberConfig	{ min: 0, max: 1000 }	The step in milliseconds between every generated timestamp
format	String	"toISOString"	A date format as defined in std/datetime or toISOString to call Date.prototype.toISOString

element

Takes a random element from the given list.

Key	Type	Default	Description
list	Array	["A", "B", "C"]	The list of elements

integer

Generates a random integer.

Key	Type	Default	Description
number	Number || NumberConfig	{ min: 0, max: 256 }	The constant number or the information to generate a random number

ipv4

Generates a list of number IPv4 addresses and takes one of the list for every line.

Key	Type	Default	Description
number	Number || NumberConfig	100	The number of different IP addresses
distribution	String	"uniform"	The distribution of the IP addresses

Run the log generator

After configuring the log file format in config.ts, the generator can be started using

deno run generate

A personal note about this project

I implemented this to generate fake log files for the exams of my students. It is their task to analyze them with the utilities available at the Linux shell, like grep, sort, uniq, wc.

A number of log files as well as the configuration to produce them are in the generated directory.

Furthermore, the project allowed me to get to know a number of new technologies and to try them:

• Deno: I'm a passionate JavaScript coder and liked it from the start.
• TypeScript: I'm still not sure about it, but it leads to a cleaner code, at it didn't allow me to access member methods using brackets. See the toISOString format above.
• Gitpod: The future of applications is the web, so go for it. Using Gitpod allowed me to change my PC without the need to re-setup my development environment (at least for this project).

Have fun using this project. Send me a message on Twitter, if you like it. PRs are welcome.