Add performance metrics.

Author: Stephan Heßelmann (lgtf/39809)

Cargo.lock

@@ -20,6 +20,7 @@ structopt = "0.3.12"
 quick-xml = "0.18.1"
 flate2 = "1.0.14"
 atty = "0.2.14"
+humantime = "2.0.0"
 
 [dev-dependencies]
 tempfile = "3.1.0"

Cargo.toml

@@ -14,12 +14,16 @@ use std::io::{self, Read, Write};
 /// extensions are placed within a `CustomerExtension` tag in within the record. `category` is used
 /// for the root tag name. `record_type` switches between `<Record>`, `<DeleteRecord>` and
 /// `<DeleteAllRecords>` in markup.
+///
+/// # Return
+///
+/// Number of processed records.
 pub fn generate_xml<O: Write, I: Read>(
     out: O,
     mut reader: CsvSource<I>,
     category: &str,
     record_type: RecordType,
-) -> io::Result<()> {
+) -> io::Result<u64> {
     let mut writer = Writer::new_with_indent(out, b'\t', 1);
     // Write declaration
     // <?xml version="1.0" encoding="UTF-8" ?>
@@ -28,13 +32,15 @@ pub fn generate_xml<O: Write, I: Read>(
         .map_err(expect_io_error)?;
     // Open root tag (Category)
     open_markup(&mut writer, category)?;
+    let mut num_records: u64 = 0;
     while let Some(record) = reader.read_record()? {
         // Write one record for each entry in csv
         write_record(&mut writer, &record, record_type.as_str())?;
+        num_records += 1;
     }
     // Close root tag (Category)
     close_markup(&mut writer, category)?;
-    Ok(())
+    Ok(num_records)
 }
 
 /// Unwraps io::error, panics if the it is not `quick_xml::Error::Io`

src/generate_xml.rs

@@ -12,6 +12,7 @@ use std::{
     io,
     path::{Path, PathBuf},
     str::FromStr,
+    time::Instant,
 };
 use structopt::StructOpt;
 use strum;
@@ -81,7 +82,18 @@ fn main() -> CliResult {
     //
     // We keep this in top level scope, since we want the progress bar to live during the whole
     // program execution, so it will be displayed.
-    let progress_bar;
+    let progress_bar = if args.input.is_file() && (args.output.is_file() || isnt(Stream::Stdout)) {
+        let progress_bar = ProgressBar::new(0);
+        let fmt = "{spinner:.green} [{elapsed_precise}] [{wide_bar:.cyan/blue}] {bytes}/{total_bytes} ({eta})";
+        progress_bar.set_style(
+            ProgressStyle::default_bar()
+                .template(fmt)
+                .progress_chars("#>-"),
+        );
+        Some(progress_bar)
+    } else {
+        None
+    };
 
     // Keep our reference to stdin alive, if need be. Only initialized if we don't read from a file
     // and read from stdin. We hold it alive at top level scop, so we can hold the lock to it, for
@@ -93,6 +105,9 @@ fn main() -> CliResult {
     // file, we open in this code).
     let std_out;
 
+    // Initial time measurement
+    let initial_time = Instant::now();
+
     let input: Box<dyn io::Read> = match args.input {
         IoArg::File(input) => {
             // Path argument specified. Open file and initialize progress bar.
@@ -104,15 +119,9 @@ fn main() -> CliResult {
             // progress bar.
             // * We don't want the Progress bar to interfere with the output, if writing to /dev/tty.
             // Progress bar interferes with formatting if stdout and stderr both go to /dev/tty
-            if args.output.is_file() || isnt(Stream::Stdout) {
+            if let Some(progress_bar) = &progress_bar {
                 let len = file.metadata()?.len();
-                progress_bar = ProgressBar::new(len);
-                let fmt = "{spinner:.green} [{elapsed_precise}] [{wide_bar:.cyan/blue}] {bytes}/{total_bytes} ({eta})";
-                progress_bar.set_style(
-                    ProgressStyle::default_bar()
-                        .template(fmt)
-                        .progress_chars("#>-"),
-                );
+                progress_bar.set_length(len);
                 let file_with_pbar = progress_bar.wrap_read(file);
 
                 if has_gz_extension(&input) {
@@ -156,7 +165,11 @@ fn main() -> CliResult {
             Box::new(writer)
         }
     };
-    generate_xml(&mut out, reader, &args.category, args.record_type)?;
+    let num_records = generate_xml(&mut out, reader, &args.category, args.record_type)?;
+    // Drop progress bar, so it's removed from stderr before we print the performance metrics.
+    // Otherwise, the drop handler would erroneously remove the lower lines of the performance metrics output.
+    std::mem::drop(progress_bar);
+    print_performance_metrics(&initial_time, num_records);
     Ok(())
 }
 
@@ -167,3 +180,11 @@ fn has_gz_extension(path: &Path) -> bool {
         _ => false,
     }
 }
+
+fn print_performance_metrics(initial_time: &Instant, num_records: u64) {
+    eprintln!(
+        "Processed {} records in {}.",
+        num_records,
+        humantime::format_duration(initial_time.elapsed())
+    );
+}