simcli

README

SimCLI

Utility to mock CLI's, simulate responses, add delays/repeats, and more. Assists testing and cross-platform development that involves executing external programs

Usage

Building / Running

# clone this respond
git clone git@github.com:davidwashere/simcli.git

# build / install globally (assumes go bin dir on path)
go install ./cmd/simcli

# then run
simcli hello

Config

SimCLI requires a config file defining the tasks to execute when specific args are supplied to simcli

Refer to simcli.yaml for an example config

By default simcli.yaml is expected in the current working directory, to change this path set it in the SIMCLI_CONFIG environment variable. Input files will be relative to the config file's directory unless the input file is an absolute path

A task defines what to do, a command chains tasks together and executes them when args are matched

Config Spec

Key	Desc
tasks	defines the list of tasks that can be used in commands
tasks.type	task type defines behavior and required fields, see Task Types section below for details
tasks.name	the unique identifier to reference this task in commands
tasks.input	the file containing the data that will be used as input to this task
tasks.initdelay	the delay, in milliseconds, to wait before starting the task (defaults to 0)
tasks.delay	the delay, in milliseconds, between each line being printed for stdout and stderr tasks (defaults to 0) Note: delay is an estimate (not high precision), for delays < 16ms output is batched to simulate expected throughput
tasks.repeat	the number of times to repeat the task, or forever to repeat forever
tasks.perms	the permission bits to set for task types that produce files in octal form (defaults to 0644)
commands	defines the possible commands to respond to
commands.args	the args exactly as they appear when passed to simcli to trigger this commands' tasks
commands.match	specifies rule for for matching args to a comand contains or exact(default: exact)
commands.tasks	the list of tasks to execute for this command
commands.rc	the return / exit code to use after all tasks are complete (defaults to 0)
defaultCommand	the default command to execute if no commands are matched, see commands above for spec

Task Types

Type	Desc
stdout	will print the contents of input file to stdout
stderr	will print the contents of input file ot stderr
file	will copy the contents of input file to outPath
hang	will cause program to hang forever

Command match

Match	Desc
exact	command matches if args string matches exactly the args passed
contains	command matches if args is contained anywhere within the args passed

Execute

To run: simcli <args>

Example:

$ simcli hello
this
is
from
hello.txt

TODO

• BUG: parse args as if real args - is bug when just doing a string compare (ie: --progress=-same)
• Validate config file (ie: no tasks missing required fields, no commands referring to unknown tasks, etc.)
• Add task for accepting data via stdin, define end condition
• Learning mode - pass args to command and record stdout, stdin, return codes, etc. and create an appropriate config
• Add ability to create a .exe using a particular name
  • Add ENVVAR / SUBCMD for creating an .exe that has a particular name that matches real CLI
  • Option to embed tasks / commands into .exe?
• Allow CLI flags with Trigger like simcli SIMCLI_FLAGS [flags]
• Randomness and/or A/B testing - certain percentage of requests or certain amount of requests before then failure or vice versa
• Restructure code for extensibility
• add debug flag and debug logging
• ability to add delays by lines, something like: 1-30:100, 31-:2000, etc.
  • a single file can be used as part of multiple tasks - if tasks could specify line numbers this could be achieved with existing api
• adjust arg parsing to not require flags in specific order and allow wildcards
• add task 'touch' w/ permissions to create an output file, or copy an output file from a dataset to an output location
• add 'cmd' task to execute an external command (no longer mocking at this point?)
• add cli args to simcli for learning, configuring, etc. - args defined in simcli.yaml take precedence
• add 'learning mode' - to capture the output of a command
• add batch param to stdout/err - cannot override batch if less than 16ms
• add stdboth task for stdout and err
• add subcommand for printing out tasks, commands, etc. per current config
• add 'API' trigger such that via curl or similar can invoke an endpoint that will trigger simcli to run a task, command, etc.
• ability to mix stderr within stdout and vice versa
  • this can be done with different files right now, so perahps not necessary