Enable logging to cli from stdin

snitch-cli/src/main.rs

@@ -1,3 +1,5 @@
+use std::io::{stdin, BufRead};
+
 use chrono::Local;
 use clap::Parser;
 use eyre::{eyre, WrapErr};
@@ -17,9 +19,13 @@ struct Opt {
     #[clap(short, long, env = "SNITCH_SEVERITY", default_value = "Error")]
     severity: Severity,
 
-    /// Name of this service
+    /// Treat each line of the message as its own log message.
+    #[clap(short, long, env = "SNITCH_LINES")]
+    lines: bool,
+
+    /// Log message to snitch. If this is omitted, the message will be read from stdin.
     #[clap(env = "SNITCH_MESSAGE")]
-    message: String,
+    message: Option<String>,
 }
 
 fn main() {
@@ -27,15 +33,55 @@ fn main() {
         eprintln!("snitch error: {e:?}");
     }
 }
+
 fn run() -> eyre::Result<()> {
     let opt = Opt::parse();
     color_eyre::install()?;
 
+    if let Some(message) = &opt.message {
+        log_from(&opt, message.as_bytes())
+    } else {
+        let stdin = stdin();
+        log_from(&opt, stdin.lock())
+    }
+}
+
+/// Consume a reader and log everything to snitch
+fn log_from(opt: &Opt, r: impl BufRead) -> eyre::Result<()> {
+    if opt.lines {
+        log_lines(opt, r)
+    } else {
+        log_reader(opt, r)
+    }
+}
+
+/// Consume a reader and log everything as a single message to snitch
+fn log_reader(opt: &Opt, mut r: impl BufRead) -> eyre::Result<()> {
+    let mut s = String::new();
+    r.read_to_string(&mut s)?;
+    log_message(opt, &s)
+}
+
+/// Log each line from a reader to snitch
+fn log_lines(opt: &Opt, r: impl BufRead) -> eyre::Result<()> {
+    for line in r.lines() {
+        let line = line.wrap_err("Failed to read from stdin")?;
+        let line = line.trim();
+        if !line.is_empty() {
+            log_message(&opt, &line)?;
+        }
+    }
+
+    Ok(())
+}
+
+/// Log a single message to snitch
+fn log_message(opt: &Opt, message: &str) -> eyre::Result<()> {
     let message = LogMsg {
         time: Some(Local::now()),
         severity: opt.severity,
-        service: opt.service,
-        message: opt.message,
+        service: opt.service.clone(),
+        message: message.to_string(),
         hostname: probe_hostname(),
         file: None,
         line: None,