#lang scribble/manual

@(require "mb-tools.rkt" scribble/eval pollen/setup (for-label (except-in racket ...) pollen/setup))

@(define my-eval (make-base-eval))
@(my-eval `(require pollen pollen/file))


@title[#:tag "raco-pollen"]{Using @exec{raco pollen}}


Racket provides centralized command-line options through @exec{raco} (short for @exec{racket command}, see @other-doc['(lib "scribblings/raco/raco.scrbl")]). 

Once you install Pollen, you can access the following Pollen-specific commands through @racket[raco] using the subcommand @exec{raco pollen}.

@section{Making sure @exec{raco pollen} works}

Open a terminal window and type:

@terminal{
> raco pollen test}

If @exec{raco pollen} is installed correctly, you'll see:

@terminal{raco pollen is installed correctly}

But if you get:

@terminal{raco: Unrecognized command: pollen}

You'll need to fix the problem before proceeding, most likely by reinstalling Pollen (see @secref["Installation" #:doc '(lib "pollen/scribblings/pollen.scrbl")]).

If your error is like this:

@terminal{Unrecognized command: raco}

You have a deeper problem with your Racket installation (often a misconfiguration of @code{PATH}).

@section{@exec{raco pollen}}

Same as @exec{raco pollen help}.

@section{@exec{raco pollen help}}

Displays a list of available commands.


@section{@exec{raco pollen start}}

Start the project server from the current directory using the default port, which is the value of the parameter @racket[current-server-port] (by default, port @id[default-project-server-port]).


This command can be invoked with two optional arguments, and two optional switches.

@racket[raco pollen start _path] will start the project server from @racket[_path] rather than the current directory (making @racket[_path] its root directory).

@terminal{
> raco pollen start ~/path/to/project/}

@racket[raco pollen start _path _port] will start the project server in @racket[_path] using @racket[_port] rather than @racket[current-server-port]. This is useful if you want to have multiple project servers running simultaneously.

@terminal{
> raco pollen start ~/path/to/project/
> raco pollen start ~/path/to/project/scribblings 8088}

If you want to start in the current directory but with a different port, use @litchar{.} as the path:

@terminal{
> raco pollen start . 8088}


@margin-note{Pollen defaults to port @id[default-project-server-port] because it's not commonly used by other network services. But Pollen has no idea what else is running on your machine. If @id[default-project-server-port] is already in use, you'll get an error when you try to start the Pollen project server. In that case, try a different port.}


Adding the optional @exec{-l} or @exec{--launch} switch will open the main project dashboard in your web browser after the project server starts.

Adding the optional @exec{--local} switch will restrict the project server to responding to requests from localhost. (By default, the project server will respond to requests from any client.)


@section{@exec{raco pollen render}}

This command can be invoked two ways: in source mode or directory mode.

In both modes, the optional @exec{--dry-run} or @exec{-d} switch prints the paths that would be rendered by this command without actually doing so. 

In both modes, the optional @exec{--force} or @exec{-f} switch forces a fresh render from source, even if the file is already cached, by updating the modification date of the file (à la @exec{touch}). Thus, if modification dates are important to you, don't use this option.

In both modes, the optional @exec{--null} or @exec{-n} switch renders as usual, but doesn't write any files. (Convenient if you're arranging special render behavior, for instance writing to a database or network server.)



@bold{Source mode}: @racket[raco pollen render _source ...] will render only the source paths specified in @racket[_source ...]. Consistent with the usual command-line idiom, this can be a single path, a list of paths, or a pattern:

@terminal{
> raco pollen render foo.html.pm
> raco pollen render foo.html.pm bar.html.pm zam.css.pp
> raco pollen render *.html.pm}

Paths can also be specified as output rather than input paths, and the corresponding source paths will be discovered:

@terminal{
> raco pollen render foo.html
> raco pollen render foo.html bar.html zam.css}

The optional @exec{--target} or @exec{-t} switch specifies the render target for multi-output source files. If the target is omitted, the renderer will use whatever target appears first in @racket[(setup:poly-targets)].

@terminal{
> raco pollen render -t pdf foo.poly.pm}

See also @seclink["raco-pollen-render-poly"].

The optional @exec{--parallel} or @exec{-p} switch creates a set of parallel rendering jobs equal to the number of processing cores on the system. On a multi-core machine, this will usually make your rendering job finish faster. The order of rendering is not guaranteed, of course, so if your project depends on a certain order of rendering, don't use this option.

@terminal{
> raco pollen render -p foo.html bar.html zam.css
}

The alternative @exec{--jobs <count>} or @exec{-j <count>} switch does the same thing, but takes one argument that creates @racket[<count>] parallel jobs (which can be more or less than the number of processing cores).

@terminal{
> raco pollen render -j 4 foo.html bar.html zam.css
}

As a rule of thumb, parallel rendering works best if you do @exec{raco setup} first, which updates Pollen's disk caches:

@terminal{
> raco setup -p
> raco pollen render -p 
}

@italic{Warning}: In all cases, the newly rendered output file will overwrite any previous output file.

@margin-note{As of mid-2020, Pollen's parallel-processing performance under the CS (= Chez Scheme) variant of Racket is worse than ordinary Racket. If you use Racket CS, you may get better results using @exec{-j 4} (which will limit the operation to four cores) than @exec{-p} (which will use all available cores).}

@bold{Directory mode}: @racket[raco pollen render _directory] renders all preprocessor source files and then all pagetree files found in the specified directory. If none of these files are found, a pagetree will be generated for the directory (which will include all source files) and then rendered. If the @racket[_directory] argument is omitted, the command defaults to the current directory.

In directory mode, this command can be invoked with two other optional arguments (in addition to the @exec{--target}, @exec{--parallel}, and  @exec{--jobs} switches mentioned above):

The @exec{--subdir} or @exec{-s} switch also renders subdirectories. @racket[current-project-root] remains fixed at the initial directory, just as it would be in the project server after invoking @racket[raco pollen start]. 

Certain subdirectories are automatically ignored, including Racket and Pollen private directories (like @tt{compiled}) and source-control directories (like @tt{.git} and @tt{.svn}). You can omit other paths by overriding @racket[default-omitted-path?]. You can override these omissions — that is, force a path to be included in a recursive render — by overriding @racket[default-extra-path?].

The @exec{--recursive} or @exec{-r} switch renders subdirectories recursively. Meaning, each subdirectory is treated like an independent subproject, and @racket[current-project-root] moves around accordingly. In many projects, there won't be any difference between the @exec{-s} and @exec{-r} switches. But if the difference matters in your project, you have them both.




@section{@exec{raco pollen publish}}

Make a copy of the project directory on the desktop, but without any source files or other Pollen-related files. (This function is pretty lame, and I invite suggestions for improvement.)

@racket[raco pollen publish _project-dir] will publish the project in @racket[_project-dir] onto the desktop in a folder called @racket[publish]. @bold{Warning}: if @racket[publish] already exists on the desktop, it will be overwritten.

@racket[raco pollen publish _project-dir _dest-dir] will publish the project in @racket[_project-dir] to @racket[_dest-dir] rather than the desktop. @bold{Warning}: if @racket[_dest-dir] already exists, it will be overwritten by the newly published directory.

If you're already in your project directory and want to publish somewhere other than the desktop, use @racket[raco pollen publish _. _dest-dir].

By default, this command will automatically overwrite the destination directory. Adding the optional @exec{-c} or @exec{--confirm} switch will ask for confirmation if the destination already exists.

You can determine the default publishing destination for a project by overriding @racket[default-publish-directory].

Certain files and directories are automatically omitted from the published directory, including Racket and Pollen sources, Pollen caches, and source-control directories (like @tt{.git} and @tt{.svn}). You can omit other files by overriding @racket[default-omitted-path?]. You can override these omissions — that is, force a path to be published — by overriding @racket[default-extra-path?].

The optional @exec{--dry-run} or @exec{-d} switch prints the source and destination directories for publishing without actually doing so. If the destination-directory path cannot be created, an error will arise.

@section{@exec{raco pollen setup}}

Finds Pollen source files in the current directory, compiles them, and loads the results into the @seclink["Cache" #:doc '(lib "pollen/scribblings/pollen.scrbl")]. This will give you the snappiest performance during an interactive session with the project server. 

Can also be invoked as @racket[raco pollen setup _directory], which will set up the files in @racket[_directory].

The optional @exec{--parallel} or @exec{-p} switch creates a set of parallel setup jobs equal to the number of processing cores on the system. On a multi-core machine, this will usually make your setup finish faster.

@terminal{
> raco pollen setup -p
}

The alternative @exec{--jobs <count>} or @exec{-j <count>} switch does the same thing, but takes one argument that creates @racket[<count>] parallel jobs (which can be more or less than the number of processing cores).

@terminal{
> raco pollen setup -j 4
}

@margin-note{As of mid-2020, Pollen's parallel-processing performance under the CS (= Chez Scheme) variant of Racket is worse than ordinary Racket. If you use Racket CS, you may get better results using @exec{-j 4} (which will limit the operation to four cores) than @exec{-p} (which will use all available cores).}

The optional @exec{--dry-run} or @exec{-d} switch prints the paths that would be compiled by this command without actually doing so.


@section{@exec{raco pollen reset}}

Resets Pollen's @seclink["Cache" #:doc '(lib "pollen/scribblings/pollen.scrbl")] by deleting the cache directories, including @tt{compiled} directories created by Racket. Use this when you need a fresh start in life.

Can also be invoked as @racket[raco pollen reset _directory], which will reset a different project @racket[_directory].

@section{@exec{raco pollen version}}

Would you believe this prints the Pollen version number.

@section{The @exec{POLLEN} environment variable}

Pollen recognizes a @exec{POLLEN} environment variable on the command line, which can be used to pass through any value you like. This value can be used within your project files with @racket[(getenv "POLLEN")], which if not set, returns @racket[#f]. Take this file, for instance:

@fileblock["test.txt.pp" @codeblock{
#lang pollen
Result is ◊or[(getenv "POLLEN")]{nothing}
}]

The @exec{POLLEN} environment variable will change how it's rendered:

@terminal{
> raco pollen render test.txt ; cat test.txt
rendering test.txt.pp
rendering: /test.txt.pp as /test.txt
Result is nothing

> POLLEN=DEBUG raco pollen render test.txt ; cat test.txt
rendering test.txt.pp
rendering: /test.txt.pp as /test.txt
Result is DEBUG

}

@section{Logging & the @exec{PLTSTDERR} environment variable}

@margin-note{See @secref["logging" #:doc '(lib "scribblings/reference/reference.scrbl")] for an introduction to Racket's logging system.}

By default, Pollen will log messages at the @racket['info] level or above to the console during any terminal session (e.g., project server or rendering job). So if you start the project server like so:

@terminal{
> raco pollen start
} 

You will see log messages starting with:

@terminal{
pollen: starting project server ...
}

And so forth.

You can use Racket's @racket[PLTSTDERR] environment variable to adjust the level of logging. If you provide an explicit log level for Pollen, it will override this default behavior. So if you only want to see messages at the @racket['error] level or above, you would invoke the project server like so:

@terminal|{
> PLTSTDERR=error@pollen raco pollen start
}|

After this, the project server will work normally, but you won't see the usual @racket['info]-level messages, and instead will only see @racket['error] messages or above.

Conversely, if you want more detailed logging, you can invoke the @racket['debug] log level like so:

@terminal|{
> PLTSTDERR=debug@pollen raco pollen start
}|

Then you'll see the usual @racket['info] messages, plus a bunch more.

