Add --env-file

Cargo.toml

@@ -24,6 +24,7 @@ name = "cargo-watch"
 camino = "1.1.2"
 cargo_metadata = "0.15.2"
 clap = "2.33.1"
+dotenvy = "0.15.6"
 log = "0.4.17"
 notify-rust = "4.7.0"
 shell-escape = "0.1.5"

cargo-watch.1.ronn

@@ -3,7 +3,9 @@ cargo-watch(1) -- watches over your Cargo project's source
 
 ## SYNOPSIS
 
-cargo watch [`--exec` | `-x` <cargo subcommand>]... [`--shell` | `-s` <command>]... [`--ignore` | `-i` <pattern>]... [`--watch` | `-w` <path>]... [`--features` <list>] [`--no-restart`] [`--watch-when-idle`] [`--clear` | `-c`] [`--use-shell` <program>] [`--workdir` | `-C` <path>] [`--postpone`] [`--poll` <interval>] [`--delay` | `-d` <seconds>] [`--no-vcs-ignores`] [`--no-dot-ignores`] [`--ignore-nothing`] [`--debug` ] [`--why`] [`--quiet`] [`--version` | `-V`] [-- <command>...]
+cargo watch [options] [`--exec` | `-x` <cargo subcommand>]... [`--shell` | `-s` <command>]... [-- <command>...]
+cargo watch [`--version` | `-V`]
+cargo watch [`--help` | `-h`]
 
 ## DESCRIPTION
 
@@ -67,11 +69,20 @@ Ignore nothing, not even target/ and .git/.
 * `-c`, `--clear`:
 Clear the screen before each run.
 
+* `-E`, `--env-var` <key>=<value>:
+Inject an environment variable.
+
+* `--env-file` <path>:
+Inject environment variables from a dotenv-style file.
+
 * `-B` <value>:
 Inject `RUST_BACKTRACE=<value>` into the environment.
 
 This is useful when panics are handled and you want a backtrace to be printed: usually you’d have to add `RUST_BACKTRACE=1` yourself, this shortens it to `-B1`!
 
+* `-L` <value>:
+Inject `RUST_LOG=<value>` into the environment.
+
 * `-C`, `--workdir` <path>:
 Change the working directory to the <path> given.
 
@@ -163,9 +174,9 @@ If you want more verbose output, try running with the `--debug` flag. Note that
 
 ### KNOWN BUGS
 
-In 7.8.0, the `--workdir` option changes the directory before any other options are processed, so e.g. `--watch` paths may not work as expected. This has to be fixed upstream, see [watchexec#188].
+In 7.8.0, the `--workdir` option changes the directory before any other options are processed, so e.g. `--watch` paths may not work as expected. This is fixed upstream in Watchexec library 2.
 
-[watchexec#188]: https://github.com/watchexec/watchexec/issues/188#issuecomment-829138116
+In 8.x, the `-B`, `-L`, `-E`, `--env-var`, `--env-file` options inject environment variables into the main cargo-watch process, which may be unsound in some situations and may also affect cargo-watch itself. This is fixed upstream in Watchexec library 2.
 
 ## TROUBLESHOOTING
 

completions/zsh

@@ -17,7 +17,9 @@ args=(
   '(-i --ignore)'{-i+,--ignore=}'[Ignore changes to paths matching the pattern]:pattern'
   '(-w --watch)'{-w+,--watch=}'[Watch a specific directory]:path:_path_files -/'
   '(-C --workdir)'{-C+,--workdir=}'[Change working directory of command]:path:_path_files -/'
+  '(-E --env-var)'{-E+,--env-var=}'[Add an environment variable to the command]:pattern'
   '-B=[Inject RUST_BACKTRACE=value into the environment]:value'
+  '-L=[Inject RUST_LOG=value into the environment]:value'
   '--no-dot-ignores[Skip .ignore files]'
   '--no-vcs-ignores[Skip .gitignore files]'
   '--ignore-nothing[Ignore nothing, not even target/ and .git/]'
@@ -31,6 +33,7 @@ args=(
   '--delay=[File updates debounce delay]:seconds'
   '--poll=[Forces polling mode]:interval'
   '--features=[List of features passed to cargo invocations]:features'
+  '--env-file=[Inject environment variables from a file]:path:_path_files -/'
   '(-)1:command: _command_names -e'
   '*::arguments:{ _comp_priv_prefix=( $cmd -n ${(kv)opt_args[-u]} ) ; _normal }'
 )

src/args.rs

@@ -204,6 +204,16 @@ pub fn parse() -> ArgMatches<'static> {
                         .min_values(1)
                         .number_of_values(1)
                 )
+                .arg(
+                    Arg::with_name("env-files")
+                        .help("Set environment variables from a .env file")
+                        .long("env-file")
+                        .takes_value(true)
+                        .multiple(true)
+                        .empty_values(false)
+                        .min_values(1)
+                        .number_of_values(1)
+                )
                 .arg(
                     Arg::with_name("rust-backtrace")
                         .help("Inject RUST_BACKTRACE=VALUE (generally you want to set it to 1) into the environment")

src/main.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use camino::Utf8PathBuf;
 use clap::values_t;
 use stderrlog::Timestamp;
@@ -51,6 +53,28 @@ fn main() -> Result<()> {
         std::env::set_var("RUST_LOG", l);
     }
 
+    if matches.is_present("env-files") {
+        for file in values_t!(matches, "env-files", PathBuf).unwrap_or_else(|e| e.exit()) {
+            for item in dotenvy::from_path_iter(&file).unwrap_or_else(|e| {
+                clap::Error::with_description(
+                    &format!("Failed to read .env file {file:?}: {e}"),
+                    clap::ErrorKind::ValueValidation,
+                )
+                .exit()
+            }) {
+                let (key, var) = item.unwrap_or_else(|e| {
+                    clap::Error::with_description(
+                        &format!("Malformed pair in .env file {file:?}: {e}"),
+                        clap::ErrorKind::ValueValidation,
+                    )
+                    .exit()
+                });
+                // Soundness: not great, it'll get better with watchexec 2
+                std::env::set_var(key, var);
+            }
+        }
+    }
+
     if matches.is_present("env-vars") {
         for pair in values_t!(matches, "env-vars", String).unwrap_or_else(|e| e.exit()) {
             if let Some((key, var)) = pair.split_once('=') {