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//! # Rust command-line library //! //! Common rust command-line macros and utilities, to write shell-script like tasks //! easily in rust programming language. Available at [crates.io](https://crates.io/crates/cmd_lib). //! //! [![Build status](https://github.com/rust-shell-script/rust_cmd_lib/workflows/ci/badge.svg)](https://github.com/rust-shell-script/rust_cmd_lib/actions) //! [![Crates.io](https://img.shields.io/crates/v/cmd_lib.svg)](https://crates.io/crates/cmd_lib) //! //! ## Why you need this //! If you need to run some external commands in rust, the //! [std::process::Command](https://doc.rust-lang.org/std/process/struct.Command.html) is a good //! abstraction layer on top of different OS syscalls. It provides fine-grained control over //! how a new process should be spawned, and it allows you to wait for process to finish and check the //! exit status or collect all of its output. However, when //! [Redirection](https://en.wikipedia.org/wiki/Redirection_(computing)) or //! [Piping](https://en.wikipedia.org/wiki/Redirection_(computing)#Piping) is needed, you need to //! set up the parent and child IO handles manually, like this in the //! [rust cookbook](https://rust-lang-nursery.github.io/rust-cookbook/os/external.html), which is often a tedious //! work. //! //! A lot of developers just choose shell(sh, bash, ...) scripts for such tasks, by using `<` to redirect input, //! `>` to redirect output and '|' to pipe outputs. In my experience, this is **the only good parts** of shell script. //! You can find all kinds of pitfalls and mysterious tricks to make other parts of shell script work. As the shell //! scripts grow, they will ultimately be unmaintainable and no one wants to touch them any more. //! //! This cmd_lib library is trying to provide the redirection and piping capabilities, and other facilities to make writing //! shell-script like tasks easily **without launching any shell**. For the //! [rust cookbook examples](https://rust-lang-nursery.github.io/rust-cookbook/os/external.html), //! they can usually be implemented as one line of rust macro with the help of this library, as in the //! [examples/rust_cookbook.rs](https://github.com/rust-shell-script/rust_cmd_lib/blob/master/examples/rust_cookbook.rs). //! Since they are rust code, you can always rewrite them in rust natively in the future, if necessary without spawning external commands. //! //! ## What this library looks like //! //! To get a first impression, here is an example from //! [examples/dd_test.rs](https://github.com/rust-shell-script/rust_cmd_lib/blob/master/examples/dd_test.rs): //! //! ```no_run //! # use byte_unit::Byte; //! # use cmd_lib::*; //! # use rayon::prelude::*; //! # use std::time::Instant; //! # const DATA_SIZE: u64 = 10 * 1024 * 1024 * 1024; // 10GB data //! # let mut file = String::new(); //! # let mut block_size: u64 = 4096; //! # let mut thread_num: u64 = 1; //! run_cmd! ( //! info "Dropping caches at first"; //! sudo bash -c "echo 3 > /proc/sys/vm/drop_caches"; //! info "Running with thread_num: $thread_num, block_size: $block_size"; //! )?; //! let cnt = DATA_SIZE / thread_num / block_size; //! let now = Instant::now(); //! (0..thread_num).into_par_iter().for_each(|i| { //! let off = cnt * i; //! let bandwidth = run_fun!( //! sudo bash -c "dd if=$file of=/dev/null bs=$block_size skip=$off count=$cnt 2>&1" //! | awk r#"/copied/{print $(NF-1) " " $NF}"# //! ) //! .unwrap(); //! cmd_info!("thread $i bandwidth: $bandwidth"); //! }); //! let total_bandwidth = //! Byte::from_bytes((DATA_SIZE / now.elapsed().as_secs()) as u128).get_appropriate_unit(true); //! cmd_info!("Total bandwidth: ${total_bandwidth}/s"); //! # Ok::<(), std::io::Error>(()) //! ``` //! //! Output will be like this: //! //! ```console //! ➜ rust_cmd_lib git:(master) ✗ cargo run --example dd_test -- -b 4096 -f /dev/nvme0n1 -t 4 //! Finished dev [unoptimized + debuginfo] target(s) in 1.56s //! Running `target/debug/examples/dd_test -b 4096 -f /dev/nvme0n1 -t 4` //! Dropping caches at first //! Running with thread_num: 4, block_size: 4096 //! thread 1 bandwidth: 286 MB/s //! thread 3 bandwidth: 269 MB/s //! thread 2 bandwidth: 267 MB/s //! thread 0 bandwidth: 265 MB/s //! Total bandwidth: 1.01 GiB/s //! ``` //! //! ## What this library provides //! //! ### Macros to run external commands //! - run_cmd! --> CmdResult //! //! ```no_run //! # use cmd_lib::run_cmd; //! let msg = "I love rust"; //! run_cmd!(echo $msg)?; //! run_cmd!(echo "This is the message: $msg")?; //! //! // pipe commands are also supported //! run_cmd!(du -ah . | sort -hr | head -n 10)?; //! //! // or a group of commands //! // if any command fails, just return Err(...) //! let file = "/tmp/f"; //! let keyword = "rust"; //! if run_cmd! { //! cat ${file} | grep ${keyword}; //! echo "bad cmd" >&2; //! ls /nofile || true; //! date; //! ls oops; //! cat oops; //! }.is_err() { //! // your error handling code //! } //! # Ok::<(), std::io::Error>(()) //! ``` //! //! - run_fun! --> FunResult //! //! ``` //! # use cmd_lib::run_fun; //! let version = run_fun!(rustc --version)?; //! eprintln!("Your rust version is {}", version); //! //! // with pipes //! let n = run_fun!(echo "the quick brown fox jumped over the lazy dog" | wc -w)?; //! eprintln!("There are {} words in above sentence", n); //! # Ok::<(), std::io::Error>(()) //! ``` //! //! ### Abstraction without overhead //! Since all the macros' lexical analysis and syntactic analysis happen at compile time, it can //! basically generate code the same as calling `std::process` APIs manually. It also includes //! command type checking, so most of the errors can be found at compile time instead of at //! runtime. //! //! ### Intuitive parameters passing //! When passing parameters to `run_cmd!` and `run_fun!` macros, if they are not part to rust //! [String literals](https://doc.rust-lang.org/reference/tokens.html#string-literals), they will be //! converted to string as an atomic component, so you don't need to quote them. The parameters will be //! like $a or ${a} in `run_cmd!` or `run_fun!` macros. //! //! ``` //! # use cmd_lib::run_cmd; //! let dir = "my folder"; //! run_cmd!(echo "Creating $dir at /tmp")?; //! run_cmd!(mkdir -p /tmp/$dir)?; //! //! // or with group commands: //! let dir = "my folder"; //! run_cmd!(echo "Creating $dir at /tmp"; mkdir -p /tmp/$dir)?; //! # Ok::<(), std::io::Error>(()) //! ``` //! You can consider "" as glue, so everything inside the quotes will be treated as a single atomic component. //! //! If they are part of [Raw string literals](https://doc.rust-lang.org/reference/tokens.html#raw-string-literals), //! there will be no string interpolation, the same as in idiomatic rust. However, you can always use `format!` macro //! to form the new string. For example: //! ```no_run //! # use cmd_lib::run_cmd; //! // string interpolation //! let key_word = "time"; //! let awk_opts = format!(r#"/{}/ {{print $(NF-3) " " $(NF-1) " " $NF}}"#, key_word); //! run_cmd!(ping -c 10 www.google.com | awk $awk_opts)?; //! # Ok::<(), std::io::Error>(()) //! ``` //! Notice here `$awk_opts` will be treated as single option passing to awk command. //! //! If you want to use dynamic parameters, you can use $[] to access vector variable: //! ```no_run //! # use cmd_lib::run_cmd; //! let gopts = vec![vec!["-l", "-a", "/"], vec!["-a", "/var"]]; //! for opts in gopts { //! run_cmd!(ls $[opts])?; //! } //! # Ok::<(), std::io::Error>(()) //! ``` //! //! ### Redirection and Piping //! Right now piping and stdin, stdout, stderr redirection are supported. Most parts are the same as in //! [bash scripts](https://www.gnu.org/software/bash/manual/html_node/Redirections.html#Redirections). //! //! ### Builtin commands //! #### cd //! cd: set process current directory, which is always enabled //! ```no_run //! # use cmd_lib::run_cmd; //! run_cmd! ( //! cd /tmp; //! ls | wc -l; //! )?; //! # Ok::<(), std::io::Error>(()) //! ``` //! Notice that builtin `cd` will only change with current scope //! and it will restore the previous current directory when it //! exits the scope. //! //! Use `std::env::set_current_dir` if you want to change the current //! working directory for the whole program. //! //! #### true //! //! Just return true without launching any processes. //! //! #### echo //! //! ``` //! # use cmd_lib::{run_cmd, use_builtin_cmd}; //! use_builtin_cmd!(true, echo); // find more builtin commands in src/builtins.rs //! run_cmd!(echo "This is from builtin command!")?; //! # Ok::<(), std::io::Error>(()) //! ``` //! //! ### Macros to register your own commands //! Declare your function with `export_cmd` attribute, and import it with `use_custom_cmd` macro: //! //! ``` //! # use cmd_lib::*; //! # use std::io::Write; //! #[export_cmd(my_cmd)] //! fn foo(env: &mut CmdEnv) -> CmdResult { //! let msg = format!("msg from foo(), args: {:?}", env.args()); //! writeln!(env.stderr(), "{}", msg)?; //! writeln!(env.stdout(), "bar") //! } //! //! use_custom_cmd!(my_cmd); //! run_cmd!(my_cmd)?; //! println!("get result: {}", run_fun!(my_cmd)?); //! # Ok::<(), std::io::Error>(()) //! ``` //! //! ### Low-level process spawning macros //! //! `spawn!()` macro executes the whole command as a child process, returning a handle to it. By //! default, stdin, stdout and stderr are inherited from the parent. To capture the output, you //! can use `spawn_with_output!()` macro instead. //! //! To get result, you can call `wait_result()` to get CmdResult/FunResult. //! //! ```no_run //! # use cmd_lib::{spawn, spawn_with_output}; //! spawn!(ping -c 10 192.168.0.1)?.wait_result()?; //! let output = spawn_with_output!(/bin/cat file.txt | sed s/a/b/)?.wait_result(); //! # Ok::<(), std::io::Error>(()) //! ``` //! //! //! ### Macros to define, get and set thread-local global variables //! - `tls_init!` to define thread local global variable //! - `tls_get!` to get the value //! - `tls_set!` to set the value //! ``` //! # use cmd_lib::{ tls_init, tls_get, tls_set }; //! tls_init!(DELAY, f64, 1.0); //! const DELAY_FACTOR: f64 = 0.8; //! tls_set!(DELAY, |d| *d *= DELAY_FACTOR); //! let d = tls_get!(DELAY); //! // check more examples in examples/tetris.rs //! ``` //! //! ## Other Notes //! //! ### Environment Variables //! //! You can use [std::env::var](https://doc.rust-lang.org/std/env/fn.var.html) to fetch the environment variable //! key from the current process. It will report error if the environment variable is not present, and it also //! includes other checks to avoid silent failures. //! //! To set environment variables, you can use [std::env::set_var](https://doc.rust-lang.org/std/env/fn.set_var.html). //! There are also other related APIs in the [std::env](https://doc.rust-lang.org/std/env/index.html) module. //! //! To set environment variables for the command only, you can put the assignments before the command. //! Like this: //! ```no_run //! # use cmd_lib::run_cmd; //! run_cmd!(FOO=100 /tmp/test_run_cmd_lib.sh)?; //! # Ok::<(), std::io::Error>(()) //! ``` //! //! ### Security Notes //! Using macros can actually avoid command injection, since we do parsing before variable substitution. //! For example, below code is fine even without any quotes: //! ``` //! # use cmd_lib::{run_cmd, CmdResult}; //! fn cleanup_uploaded_file(file: &str) -> CmdResult { //! run_cmd!(/bin/rm -f /var/upload/$file) //! } //! ``` //! It is not the case in bash, which will always do variable substitution at first. //! //! ### Glob/Wildcard //! //! This library does not provide glob functions, to avoid silent errors and other surprises. //! You can use the [glob](https://github.com/rust-lang-nursery/glob) package instead. //! //! ### Thread Safety //! //! This library tries very hard to not set global states, so parallel `cargo test` can be executed just fine. //! The only known APIs not supported in multi-thread environment are the //! `tls_init/tls_get/tls_set` macros, and you should only use them for *thread local* variables. //! pub use cmd_lib_macros::{ cmd_debug, cmd_die, cmd_echo, cmd_error, cmd_info, cmd_trace, cmd_warn, export_cmd, run_cmd, run_fun, spawn, spawn_with_output, use_builtin_cmd, use_custom_cmd, }; pub type FunResult = std::io::Result<String>; pub type CmdResult = std::io::Result<()>; pub use builtins::{ builtin_cat, builtin_debug, builtin_die, builtin_echo, builtin_error, builtin_info, builtin_trace, builtin_true, builtin_warn, }; #[doc(hidden)] pub use log; pub use logger::init_builtin_logger; pub use process::{export_cmd, set_debug, set_pipefail, Cmd, CmdEnv, Cmds, GroupCmds, Redirect}; mod builtins; mod io; mod logger; mod process; mod thread_local;