blade

Blade

Blade is a task runner designed to be an small and easy to use task runner and a replacement when using makefiles for not intended use.

Features

• Define tasks in lua
• Command line parameters are passed to the task
• Automatic generated documentation
• Create custom help messages for build targets
• Create custom bash completion for build targets
• Easily run shell commands
• Built in file watcher
• Easy install - one binary

Install

To build from source you need Go

go get github.com/otm/blade
go install github.com/otm/blade

Pre built binaries can be downloaded at https://github.com/otm/blade/releases/latest

Cross Compile

Getting blade to all your favorite platforms. Cross compiling can easily be done with gox. See https://github.com/mitchellh/gox for information about the tool. To setup and cross compile you can run.

blade goxSetup
blade build

Bash Completion

The -generate-bash-conf option outputs the bash completion configuration to stdout. Either manually copy it or you can for instance use tee:

blade -generate-bash-conf | sudo tee /etc/bash_completion.d/blade

Note: The location of the bash completion configuration might differ depending on distribution and platform

Note: zsh can also run bash completion commands.

Getting Started

Create a Bladerunner file. All targets will be executed with the current directory set to the directory containing the Bladerunner file. The blade command will search for the Bladerunner file in the file tree.

To create a hello target define a function on the target table. In the function you can execute arbitrary lua code.

function target.hello()
  print("hello world")
end

To execute the target run

blade hello

Let's add a friendly help message to our target. That is done by creating a Lua comment on the function.

-- prints a "hello world" message
function target.hello()
  print("hello world")
end

Running blade or blade help will now create the following message:

Usage: blade [OPTION] [<target>] [<args>]

Options:
  -comp-cwords=0: Used for bash compleation
  -compgen=false: Used for bash compleation
  -debug=false: Enable debug output
  -f="": Absolute path to non default blade file
  -generate-bash-conf=false: Generate bash completion configuration

Targets:
  hello: prints a "hello world" message

Lets expand the example by processing command line parameters.

-- <lua|shell> - prints a "hello world" message in Lua or Shell
function target.hello(use)
  use = use or "lua"

  if use == "shell" then
    blade.sh([[echo "hello world"]])
  elseif use == "lua" then
    print("hello world")
  else
    print("unknown option: " .. use)
  end
end

Run the following to test the new target

blade hello
blade hello lua
blade hello shell
blade hello foo
blade help

Targets

Defining new blade targets is done by adding functions to the target table.

Example:

function target.build()
  -- build target code
end

Example: arguments

function target.install(devDeps)
  -- install target code
  -- example setting default values
  devDeps = devDeps or "true"
end

Example: variable arguments

function target.install(...)
  -- If the ... notation is used arguments are assigned to the arg variable
  -- arg.n is special and returns the number of elements in arg
  -- To test: blade install -i --dev /var/log
  print("Number of inputs: ", arg.n)
  for index, value in ipairs(arg) do
    print(index, "=", value)
  end
end

target: help

The only built in target is help. It will print an automatically generated help message. It is possible to target help messages, see blade.help

blade help

target:

If not defining a target when running blade the help target will be executed. This can be overridden by setting blade.default.

Example:

-- set the default target to `test`
blade.default = target.test

-- run a custom function for the default target
function blade.default()
  -- default target code
end

Setup and teardown

It is possible to run setup and teardown code that is run before and after the blade target. Both setup and teardown receive a target argument with the name of the current target to be run. If no target has been defined at the command line target will be an empty string. Returning false in the setup or teardown will abort the target execution.

blade.setup(target)

Example:

function blade.setup(target)
  -- setup code
end

teardown(target)

Example:

function blade.teardown(target)
  -- teardown code
end

Blade API

A small set of convince functions are provided, attached to a lua table called blade.

blade.shell(shell) => shell

The default shell used is bash, setting the blade.shell variable overrides that.

Example:

sh = blade.shell("zsh")
print(sh)
-- prints 'zsh'

blade.sh(command) => exitStatus, stdout, stderr

Run arbitrary shell commands, executed in bash by default. If the command returns a non zero exit code the target execution will be aborted. The command is echoed to stdout, to suppress this use blade._sh instead.

Returns the exit status and the standard output from the command

Example:

exitStatus, out = blade.sh("echo 'Hello World'")
-- outputs:
-- echo 'Hello World'
-- Hello World

exitStatus, out = blade._sh("echo 'Hello World'")
-- outputs:
-- Helo World

blade.exec(command) => exitStatus, stdout, stderr

runner.exec, does not abort target execution if the command returns a non zero exit code. runner._exec will suppress the command echo to stdout.

Example:

blade.exec("false'")
print("command execution continues")

blade._exec("false")
print("commnd is not echoed to stdout, execution continues")

blade.sh("false")
print("This is not executed")

blade.system(command) => exitStatus, stdout, stderr

Like blade.sh but does not check anything, or echo anything.

Example:

code, out, err = blade.system("echo 'Hello World' && date -r")
print("code:", code)
print("stdout:", out)
print("stderr", err)

blade.printStatus(message, status)

Prints a pretty printed status message to the terminal, normaly used for printing execution status.

Example:

blade.printStatus("true", true)
blade.printStatus("false", false)
blade.printStatus("0", 0)
blade.printStatus("1", 1)
blade.printStatus("nil")
blade.printStatus("true (shell)", blade._exec("true"))
blade.printStatus("false (shell)", blade._exec("false"))
-- outputs
-- true                                                                  [ ok ]
-- false                                                                 [fail]
-- 0                                                                     [ ok ]
-- 1                                                                     [fail]
-- nil                                                                   [udef]
-- true (shell)                                                          [ ok ]
-- false (shell)                                                         [fail]

blade.help(target, message)

blade.help associates a message with a target.

Example:

function target.build()
  -- build target code
end

blade.help(target.build, "<dev|prod>")

blade.compgen(target, optsOrFunction)

blade.compgen associates an opts string or a function that will be executed by blade if bash completion is set up. The function signature is:

function(compWords, compCWord)

• compWords: a table containing the arguments on the command line
• compCWord: a int pointing to the cursor position (zero indexed)

Note on cursor position: (cursor denoted by "|")

• blade target | ==> compWords = { target }, compCWord = 1
• blade target opt1| ==> compWords = { target, opt1 }, compCWord = 1
• balde target opt1 | ==> compWords = { target, opt1 }, compCWord = 2

Example:

function target.build()
  -- build target code
end

-- bind a static string
blade.compgen(target.build, "dev prod")

-- bind a function
blade.compgen(target.build, function(compWords, compCWord)
if compCWord == 1 then
   return "dev prod"
 end
 return ""
end)

Plugins

blade.plugin.watch{callback, dir, recursive, filter, exclude}

blade have a built-in simple file watcher.

• callback - function(file, op): function for processing file events
• dir - string: the directory to watch
• recursive - bool: watch sub directories recursively
• filter - string: files matching regexp will be sent processed
• exclude - {string, ...}: a table of strings of directories to exclude

Note: Several watch statements can be specified in one target

function cmd.watch()
	blade.plugin.watch{callback=onFileEvent, dir="."}
end

function onFileEvent(file, op)
  print("File: " .. file .. ", Operation: " .. op)
end

Lua

This section contains some Lua tips for new users

• Define strings: "str", 'str' or [[str]]
• Read environment variables: os.getenv("HOME")
• if-else: if <statement> then <code> elseif <statement> then <code> else <code> end
• named function variables: fn{key=name, ...} equivalent: arg = {key=name, ...}; fn(arg)
• reading files in directory:

for file in io.popen("ls -1 *.go"):lines() do
  --use file
end

string:split(sep, cb) => iterator

Splitting strings can be done in many ways in Lua but they are all quite cumbersome. To aid this there is a non standard Lua function for splitting strings in blade

Example:

out = "first\nsecond"
for line in out:split("\n") do
  print("i", line)
end

out:split("\n", function(line)
  print("cb", line)
end)