uses clap instead of custom cli arg parsing #271

kbknapp · 2020-02-23T19:25:35Z

This commit uses clap to handle
command line arugments instead of a custom rolled solution. The benefit
that clap handles all validation as well as providing many "quality of
life" or UX improvements such as hidden alias, suggestions on typo,
auto-generated help, etc.

A previous branch of this project used
structopt (which internally uses
clap). structopt makes heavy use of Rust's Custom Derive feature to
make the code less verbose and more ergonomic. clap is nearing it's v3
release, which pulls structopt into the mainline code base. This
commit does not use the v3 structopt-like feature-set since that
release is still in alpha. This meanas the code is more verbose (yet
just as performant), and could be changed to the structopt-like
features once clap v3 is officially released.

This commit also does not utilize some of clap's other features like the
ability to generate Shell Completion scripts
which could be added later if desired.

This commit is nearly a 1:1 translation from the original home rolled,
to using clap. I say "nearly" because clap adds many features on top
of what the home rolled solution provided "for free" as in with no
additional configuration. Those features include:

Argument validation: --routes, --dns-servers, and --port all now
have built in validation. If someone enters an IP that isn't valid, or a
port that isn't valid an error is returned with a friendly message prior
to advancing into gnirehtet code. --routes also checks the CIDR for
validity as well.
Auto generated help message
Suggestions on typos (this feature could be turned off to reduce the
binary size, see below)
Hidden Command aliases; The following hidden aliases have been added for
commands:
- rt which maps to run: I noticed gnirehtet rt used to be used for gnirehtet run
Long options for arguments (i.e. --port as well as -p)
Hidden Argument aliases; the following hidden aliases have been added
for arguments (which provides help for common typos):
- --dns-server -> --dns -> --dns-servers: All of these map to the same thing
- --route -> --routes
Long and Short help messages: clap allows one to specify a short
message for arguments and commands when -h is used, and display a
longer more comprehensive message when --help is used.
Multiple ways to get help: clap provides -h|--help for the base
gnirehtet command, as well as all it's subcommands, i.e. gnirehtet run --help. There is also a help subcommand gnirehtet help which
can be used alone or to display other commands, i.e. gnirehtet help run. This helps because people assume various forms of help, and should
be able to find the help messages no matter how they originally try it.

Binary Size

I see that binary size is a concern. This is the size after this commit:

❯ ls -l target/release/gnirehtet
.rwxrwxr-x 2.2M kevin 23 Feb 13:22 target/release/gnirehtet
❯ strip -g target/release/gnirehtet
❯ ls -l target/release/gnirehtet
.rwxrwxr-x 1.1M kevin 23 Feb 13:22 target/release/gnirehtet
❯ strip -s target/release/gnirehtet
❯ ls -l target/release/gnirehtet
.rwxrwxr-x 973k kevin 23 Feb 13:22 target/release/gnirehtet

So it does increase the binary size, but not dramatically. By further
turning off clap's default cargo
features,
the size may be able to be reduced even more. However, I also am a firm believer that these slight
increases are well worth the features they provide.

Relates to #243

rom1v · 2020-02-23T19:53:21Z

Oh, that's great, thank you! 👍

I'll review as soon as I have time to work on gnirehtet. 😉

This commit uses [clap](https://github.com/clap-rs/clap) to handle command line arugments instead of a custom rolled solution. The benefit that `clap` handles all validation as well as providing many "quality of life" or UX improvements such as hidden alias, suggestions on typo, auto-generated help, etc. A previous branch of this project used [structopt](https://github.com/TeXitoi/structopt) (which internally uses `clap`). `structopt` makes heavy use of Rust's Custom Derive feature to make the code less verbose and more ergonomic. `clap` is nearing it's v3 release, which pulls `structopt` into the mainline code base. This commit does not use the v3 `structopt`-like feature-set since that release is still in alpha. This meanas the code is more verbose (yet just as performant), and could be changed to the `structopt`-like features once `clap` v3 is officially released. This commit also does not utilize some of `clap`'s other features like the ability to generate [Shell Completion scripts](https://docs.rs/clap/2.33.0/clap/struct.App.html#method.gen_completions) which could be added later if desired. This commit is *nearly* a 1:1 translation from the original home rolled, to using `clap`. I say "nearly" because `clap` adds many features on top of what the home rolled solution provided "for free" as in with no additional configuration. Those features include: * Argument validation: `--routes`, `--dns-servers`, and `--port` all now have built in validation. If someone enters an IP that isn't valid, or a port that isn't valid an error is returned with a friendly message prior to advancing into `gnirehtet` code. `--routes` also checks the CIDR for validity as well. * Auto generated help message * Suggestions on typos (this feature could be turned off to reduce the binary size, see below) * [Hidden Command aliases](https://docs.rs/clap/2.33.0/clap/struct.App.html#method.alias); The following hidden aliases have been added for commands: * `rt` which maps to `run`: I noticed `gnirehtet rt` used to be used for `gnirehtet run` * Long options for arguments (i.e. `--port` as well as `-p`) * [Hidden Argument aliases](https://docs.rs/clap/2.33.0/clap/struct.Arg.html#method.alias); the following hidden aliases have been added for arguments (which provides help for common typos): * `--dns-server` -> `--dns` -> `--dns-servers`: All of these map to the same thing * `--route` -> `--routes` * Long and Short help messages: `clap` allows one to specify a short message for arguments and commands when `-h` is used, and display a longer more comprehensive message when `--help` is used. * Multiple ways to get help: `clap` provides `-h`|`--help` for the base `gnirehtet` command, as well as all it's subcommands, i.e. `gnirehtet run --help`. There is also a `help` subcommand `gnirehtet help` which can be used alone or to display other commands, i.e. `gnirehtet help run`. This helps because people assume various forms of help, and should be able to find the help messages no matter how they originally try it. Binary Size: I see that binary size is a concern. This is the size after this commit: ``` ❯ ls -l target/release/gnirehtet .rwxrwxr-x 2.2M kevin 23 Feb 13:22 target/release/gnirehtet ❯ strip -g target/release/gnirehtet ❯ ls -l target/release/gnirehtet .rwxrwxr-x 1.1M kevin 23 Feb 13:22 target/release/gnirehtet ❯ strip -s target/release/gnirehtet ❯ ls -l target/release/gnirehtet .rwxrwxr-x 973k kevin 23 Feb 13:22 target/release/gnirehtet ``` So it does increase the binary size, but not dramatically. By further turning off [`clap`'s default cargo features](https://github.com/clap-rs/clap/#optional-dependencies--features), the size may be able to be reduced even more. However, I also am a firm believer that these slight increases are well worth the features they provide. Relates to Genymobile#243 wip: clap

rom1v · 2020-08-08T13:02:13Z

Hi,

Sorry for the delay.

I quickly looked at it today, but I have this issue:

$ ./gnirehtet uninstall
error: The argument 'port' wasn't found

This is weird, because "port" is not passed as argument to "uninstall" in clap.

Btw, I rebased on dev (I also replaced 24.24.24.24/8 (which is not valid) by 192.168.0.0/16 in the doc): pr271.

kmod-midori · 2021-07-27T05:59:18Z

relay-rust/src/cli_args.rs

+            serial: m.value_of("serial").map(ToOwned::to_owned),
+            dns_servers: m.value_of("dns-servers").map(ToOwned::to_owned),
+            routes: m.value_of("routes").map(ToOwned::to_owned),
+            port: value_t_or_exit!(m.value_of("port"), u16),


I suppose this should not be written in the current way, as some sub-commands does not even have port defined, even though port has a default value?

kbknapp force-pushed the cli-rust-redo branch from c72dcd6 to d0d4479 Compare February 24, 2020 01:51

kmod-midori reviewed Jul 27, 2021

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uses clap instead of custom cli arg parsing #271

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