[pmg-devel] [PATCH log-tracker] use pico-args instead of clap

Dominik Csapak d.csapak at proxmox.com
Tue Oct 24 14:55:21 CEST 2023


Instead of upgrading from clap3 to clap4 (which seems to change their
interface every year or so), switch to the much smaller pico-args.

It has almost all features we need (except producing help output), but
wihout any dependencies. This increases compile time and reduces the
size of the resulting binary. It also reduces the lines of code.

The only difference is now the different output for errors, e.g. for
missing values of options.

Help output is copied from the old clap output.

Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
---
 Cargo.toml  |   2 +-
 src/main.rs | 223 +++++++++++++++++++---------------------------------
 2 files changed, 83 insertions(+), 142 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 725976f..82a9a4f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,7 +11,7 @@ exclude = [ "build", "debian" ]
 
 [dependencies]
 anyhow = "1"
-clap = { version = "3.2.23", features = ["cargo"] }
 flate2 = "1.0"
 libc = "0.2"
 proxmox-time = "1.1"
+pico-args = { version = "0.4", features = ["combined-flags"] }
diff --git a/src/main.rs b/src/main.rs
index e55f17b..45b0eca 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -13,111 +13,55 @@ use anyhow::{bail, Error};
 use flate2::read;
 use libc::time_t;
 
-use clap::{App, Arg};
-
 mod time;
 use time::{Tm, CAL_MTOD};
 
+fn print_usage() {
+    println!(
+        "\
+pmg-log-tracker {}
+Proxmox Mailgateway Log Tracker. Tool to scan mail logs.
+
+USAGE:
+    pmg-log-tracker [OPTIONS]
+
+OPTIONS:
+    -e, --endtime <TIME>            End time (YYYY-MM-DD HH:MM:SS) or seconds since epoch
+    -f, --from <SENDER>             Mails from SENDER
+    -g, --exclude-greylist          Exclude greylist entries
+    -h, --host <HOST>               Hostname or Server IP
+        --help                      Print help information
+    -i, --inputfile <INPUTFILE>     Input file to use instead of /var/log/syslog, or '-' for stdin
+    -l, --limit <MAX>               Print MAX entries [default: 0]
+    -m, --message-id <MSGID>        Message ID (exact match)
+    -n, --exclude-ndr               Exclude NDR entries
+    -q, --queue-id <QID>            Queue ID (exact match), can be specified multiple times
+    -s, --starttime <TIME>          Start time (YYYY-MM-DD HH:MM:SS) or seconds since epoch
+    -t, --to <RECIPIENT>            Mails to RECIPIENT
+    -v, --verbose                   Verbose output, can be specified multiple times
+    -V, --version                   Print version information
+    -x, --search-string <STRING>    Search for string",
+        env!("CARGO_PKG_VERSION")
+    );
+}
+
 fn main() -> Result<(), Error> {
-    let matches = App::new(clap::crate_name!())
-        .version(clap::crate_version!())
-        .about(clap::crate_description!())
-        .arg(
-            Arg::with_name("verbose")
-                .short('v')
-                .long("verbose")
-                .help("Verbose output, can be specified multiple times")
-                .action(clap::ArgAction::Count),
-        )
-        .arg(
-            Arg::with_name("inputfile")
-                .short('i')
-                .long("inputfile")
-                .help("Input file to use instead of /var/log/syslog, or '-' for stdin")
-                .value_name("INPUTFILE"),
-        )
-        .arg(
-            Arg::with_name("host")
-                .short('h')
-                .long("host")
-                .help("Hostname or Server IP")
-                .value_name("HOST"),
-        )
-        .arg(
-            Arg::with_name("from")
-                .short('f')
-                .long("from")
-                .help("Mails from SENDER")
-                .value_name("SENDER"),
-        )
-        .arg(
-            Arg::with_name("to")
-                .short('t')
-                .long("to")
-                .help("Mails to RECIPIENT")
-                .value_name("RECIPIENT"),
-        )
-        .arg(
-            Arg::with_name("start")
-                .short('s')
-                .long("starttime")
-                .help("Start time (YYYY-MM-DD HH:MM:SS) or seconds since epoch")
-                .value_name("TIME"),
-        )
-        .arg(
-            Arg::with_name("end")
-                .short('e')
-                .long("endtime")
-                .help("End time (YYYY-MM-DD HH:MM:SS) or seconds since epoch")
-                .value_name("TIME"),
-        )
-        .arg(
-            Arg::with_name("msgid")
-                .short('m')
-                .long("message-id")
-                .help("Message ID (exact match)")
-                .value_name("MSGID"),
-        )
-        .arg(
-            Arg::with_name("qids")
-                .short('q')
-                .long("queue-id")
-                .help("Queue ID (exact match), can be specified multiple times")
-                .value_name("QID")
-                .multiple(true)
-                .number_of_values(1),
-        )
-        .arg(
-            Arg::with_name("search")
-                .short('x')
-                .long("search-string")
-                .help("Search for string")
-                .value_name("STRING"),
-        )
-        .arg(
-            Arg::with_name("limit")
-                .short('l')
-                .long("limit")
-                .help("Print MAX entries")
-                .value_name("MAX")
-                .default_value("0"),
-        )
-        .arg(
-            Arg::with_name("exclude_greylist")
-                .short('g')
-                .long("exclude-greylist")
-                .help("Exclude greylist entries"),
-        )
-        .arg(
-            Arg::with_name("exclude_ndr")
-                .short('n')
-                .long("exclude-ndr")
-                .help("Exclude NDR entries"),
-        )
-        .get_matches();
+    let mut args = pico_args::Arguments::from_env();
+    if args.contains("--help") {
+        print_usage();
+        return Ok(());
+    }
 
     let mut parser = Parser::new()?;
-    parser.handle_args(matches)?;
+    parser.handle_args(&mut args)?;
+
+    let remaining_options = args.finish();
+    if !remaining_options.is_empty() {
+        bail!(
+            "Found invalid arguments: {:?}",
+            remaining_options.join(", ".as_ref())
+        )
+    }
 
     println!("# LogReader: {}", std::process::id());
     println!("# Query options");
@@ -1970,16 +1914,16 @@ impl Parser {
         count + 1
     }
 
-    fn handle_args(&mut self, args: clap::ArgMatches) -> Result<(), Error> {
-        if let Some(inputfile) = args.value_of("inputfile") {
-            self.options.inputfile = inputfile.to_string();
+    fn handle_args(&mut self, args: &mut pico_args::Arguments) -> Result<(), Error> {
+        if let Some(inputfile) = args.opt_value_from_str(["-i", "--inputfile"])? {
+            self.options.inputfile = inputfile;
         }
 
-        if let Some(start) = args.value_of("start") {
-            if let Ok(res) = time::strptime(start, c_str!("%F %T")) {
+        if let Some(start) = args.opt_value_from_str::<_, String>(["-s", "--starttime"])? {
+            if let Ok(res) = time::strptime(&start, c_str!("%F %T")) {
                 self.options.start = res.as_utc_to_epoch();
                 self.start_tm = res;
-            } else if let Ok(res) = time::strptime(start, c_str!("%s")) {
+            } else if let Ok(res) = time::strptime(&start, c_str!("%s")) {
                 self.options.start = res.as_utc_to_epoch();
                 self.start_tm = res;
             } else {
@@ -1994,11 +1938,11 @@ impl Parser {
             self.start_tm = ltime;
         }
 
-        if let Some(end) = args.value_of("end") {
-            if let Ok(res) = time::strptime(end, c_str!("%F %T")) {
+        if let Some(end) = args.opt_value_from_str::<_, String>(["-e", "--endtime"])? {
+            if let Ok(res) = time::strptime(&end, c_str!("%F %T")) {
                 self.options.end = res.as_utc_to_epoch();
                 self.end_tm = res;
-            } else if let Ok(res) = time::strptime(end, c_str!("%s")) {
+            } else if let Ok(res) = time::strptime(&end, c_str!("%s")) {
                 self.options.end = res.as_utc_to_epoch();
                 self.end_tm = res;
             } else {
@@ -2013,53 +1957,50 @@ impl Parser {
             bail!("end time before start time");
         }
 
-        self.options.limit = match args.value_of("limit") {
+        self.options.limit = match args.opt_value_from_str::<_, String>(["-l", "--limit"])? {
             Some(l) => l.parse().unwrap(),
             None => 0,
         };
 
-        if let Some(qids) = args.values_of("qids") {
-            for q in qids {
-                let ltime: time_t = 0;
-                let rel_line_nr: libc::c_ulong = 0;
-                let input = CString::new(q)?;
-                let bytes = concat!("T%08lXL%08lX", "\0");
-                let format =
-                    unsafe { std::ffi::CStr::from_bytes_with_nul_unchecked(bytes.as_bytes()) };
-                if unsafe {
-                    libc::sscanf(input.as_ptr(), format.as_ptr(), &ltime, &rel_line_nr) == 2
-                } {
-                    self.options
-                        .match_list
-                        .push(Match::RelLineNr(ltime, rel_line_nr));
-                } else {
-                    self.options
-                        .match_list
-                        .push(Match::Qid(q.as_bytes().into()));
-                }
+        while let Some(q) = args.opt_value_from_str::<_, String>(["-q", "--queue-id"])? {
+            let ltime: time_t = 0;
+            let rel_line_nr: libc::c_ulong = 0;
+            let input = CString::new(q.as_str())?;
+            let bytes = concat!("T%08lXL%08lX", "\0");
+            let format = unsafe { std::ffi::CStr::from_bytes_with_nul_unchecked(bytes.as_bytes()) };
+            if unsafe { libc::sscanf(input.as_ptr(), format.as_ptr(), &ltime, &rel_line_nr) == 2 } {
+                self.options
+                    .match_list
+                    .push(Match::RelLineNr(ltime, rel_line_nr));
+            } else {
+                self.options
+                    .match_list
+                    .push(Match::Qid(q.as_bytes().into()));
             }
         }
 
-        if let Some(from) = args.value_of("from") {
-            self.options.from = from.to_string();
+        if let Some(from) = args.opt_value_from_str(["-f", "--from"])? {
+            self.options.from = from;
         }
-        if let Some(to) = args.value_of("to") {
-            self.options.to = to.to_string();
+        if let Some(to) = args.opt_value_from_str(["-t", "--to"])? {
+            self.options.to = to;
         }
-        if let Some(host) = args.value_of("host") {
-            self.options.host = host.to_string();
+        if let Some(host) = args.opt_value_from_str(["-h", "--host"])? {
+            self.options.host = host;
         }
-        if let Some(msgid) = args.value_of("msgid") {
-            self.options.msgid = msgid.to_string();
+        if let Some(msgid) = args.opt_value_from_str(["-m", "--msgid"])? {
+            self.options.msgid = msgid;
         }
 
-        self.options.exclude_greylist = args.is_present("exclude_greylist");
-        self.options.exclude_ndr = args.is_present("exclude_ndr");
+        self.options.exclude_greylist = args.contains(["-g", "--exclude-greylist"]);
+        self.options.exclude_ndr = args.contains(["-n", "--exclude-ndr"]);
 
-        self.options.verbose = args.get_count("verbose") as _;
+        while args.contains(["-v", "--verbose"]) {
+            self.options.verbose += 1;
+        }
 
-        if let Some(string_match) = args.value_of("search") {
-            self.options.string_match = string_match.to_string();
+        if let Some(string_match) = args.opt_value_from_str(["-x", "--search-string"])? {
+            self.options.string_match = string_match;
         }
 
         Ok(())
-- 
2.30.2





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