Implement timehist subcommand

Cargo.toml

@@ -11,6 +11,7 @@ yansi = "0.5.0"
 isatty = "0.1"
 derive_builder = "0.10.0"
 regex = "1.4.5"
+chrono = "0.4"
 
 [dev-dependencies]
 float_eq = "0.5.0"

README.md

@@ -20,7 +20,7 @@ terminal.
 Type `lowcharts --help`, or `lowcharts PLOT-TYPE --help` for a complete list of
 options.
 
-Currently three basic types of plots are supported:
+Currently four basic types of plots are supported:
 
 #### Bar chart for matches in the input
 
@@ -95,6 +95,34 @@ of a metric over time, but not the speed of that evolution.
 
 There is regex support for this type of plots.
 
+#### Time Histogram
+
+This chart is generated using  `strace -tt ls -lR * 2>&1 | lowcharts timehist --intervals 10`:
+
+[![Sample plot with lowcharts](resources/timehist-example.png)](resources/timehist-example.png)
+
+Things like `lowcharts timehist --regex ' 404 ' nginx.log` should work in a
+similar way, and would give you a glimpse of when and how many 404s are being
+triggered in your server.
+
+The idea is to depict the frequency of logs that match a regex (by default any
+log that is read by the tool).  The sub-command can autodetect the more common
+(in my personal and biased experience) datetime/timestamp formats: rfc 3339, rfc
+2822, python `%(asctime)s`, golang default log format, nginx, rabbitmq, strace
+-t (or -tt, or -ttt),ltrace,... as long as the timestamp is present in the first
+line in the log and the format is consistent in all the lines that contain
+timestamp.  It is ok to have lines with no timestamp.  The consistency is
+required because of performance reasons: the 1st log line is the only one that
+triggers the heuristics needed to create an specialized datetime parser on the
+fly.
+
+However, if you have a format that lowcharts cannot autodetected, you can
+specify it via command line flag.  For instance, `--format
+'%d-%b-%Y::%H:%M:%S'`.  Note that, as of today, you need to leave out the
+timezone part of the format string (the autodetection works fine with
+timezones).
+
+
 ### Installing
 
 #### Via release

src/app.rs

@@ -1,6 +1,32 @@
 use clap::{self, App, AppSettings, Arg};
 
-fn add_common_options(app: App) -> App {
+fn add_input(app: App) -> App {
+    app.arg(
+        Arg::new("input")
+            .about("Input file")
+            .default_value("-")
+            .long_about("If not present or a single dash, standard input will be used"),
+    )
+}
+
+fn add_min_max(app: App) -> App {
+    app.arg(
+        Arg::new("max")
+            .long("max")
+            .short('M')
+            .about("Filter out values bigger than this")
+            .takes_value(true),
+    )
+    .arg(
+        Arg::new("min")
+            .long("min")
+            .short('m')
+            .about("Filter out values smaller than this")
+            .takes_value(true),
+    )
+}
+
+fn add_regex(app: App) -> App {
     const LONG_RE_ABOUT: &str = "\
 A regular expression used for capturing the values to be plotted inside input
 lines.
@@ -15,60 +41,44 @@ Examples of regex are ' 200 \\d+ ([0-9.]+)' (where there is one anonymous captur
 group) and 'a(a)? (?P<value>[0-9.]+)' (where there are two capture groups, and
 the named one will be used).
 ";
-
     app.arg(
-        Arg::new("max")
-            .long("max")
-            .short('M')
-            .about("Filter out values bigger than this")
-            .takes_value(true),
-    )
-    .arg(
-        Arg::new("min")
-            .long("min")
-            .short('m')
-            .about("Filter out values smaller than this")
+        Arg::new("regex")
+            .long("regex")
+            .short('R')
+            .about("Use a regex to capture input values")
+            .long_about(LONG_RE_ABOUT)
             .takes_value(true),
     )
-    .arg(
+}
+
+fn add_width(app: App) -> App {
+    app.arg(
         Arg::new("width")
             .long("width")
             .short('w')
             .about("Use this many characters as terminal width")
             .default_value("110")
             .takes_value(true),
     )
-    .arg(
-        Arg::new("regex")
-            .long("regex")
-            .short('R')
-            .about("Use a regex to capture input values")
-            .long_about(LONG_RE_ABOUT)
+}
+
+fn add_intervals(app: App) -> App {
+    app.arg(
+        Arg::new("intervals")
+            .long("intervals")
+            .short('i')
+            .about("Use no more than this amount of buckets to classify data")
+            .default_value("20")
             .takes_value(true),
     )
-    .arg(
-        Arg::new("input")
-            .about("Input file")
-            .default_value("-")
-            .long_about("If not present or a single dash, standard input will be used"),
-    )
 }
 
 pub fn get_app() -> App<'static> {
     let mut hist = App::new("hist")
         .version(clap::crate_version!())
         .setting(AppSettings::ColoredHelp)
-        .about("Plot an histogram from input values")
-        .arg(
-            Arg::new("intervals")
-                .long("intervals")
-                .short('i')
-                .about("Use no more than this amount of buckets to classify data")
-                .default_value("20")
-                .takes_value(true),
-        );
-
-    hist = add_common_options(hist);
+        .about("Plot an histogram from input values");
+    hist = add_input(add_regex(add_width(add_min_max(add_intervals(hist)))));
 
     let mut plot = App::new("plot")
         .version(clap::crate_version!())
@@ -82,34 +92,33 @@ pub fn get_app() -> App<'static> {
                 .default_value("40")
                 .takes_value(true),
         );
-    plot = add_common_options(plot);
+    plot = add_input(add_regex(add_width(add_min_max(plot))));
 
-    let matches = App::new("matches")
+    let mut matches = App::new("matches")
         .version(clap::crate_version!())
         .setting(AppSettings::ColoredHelp)
         .setting(AppSettings::AllowMissingPositional)
-        .about("Plot barchar with counts of occurences of matches params")
+        .about("Plot barchar with counts of occurences of matches params");
+    matches = add_input(add_width(matches)).arg(
+        Arg::new("match")
+            .about("Count maches for those strings")
+            .required(true)
+            .takes_value(true)
+            .multiple(true),
+    );
+
+    let mut timehist = App::new("timehist")
+        .version(clap::crate_version!())
+        .setting(AppSettings::ColoredHelp)
+        .about("Plot histogram with amount of matches over time")
         .arg(
-            Arg::new("width")
-                .long("width")
-                .short('w')
-                .about("Use this many characters as terminal width")
-                .default_value("110")
+            Arg::new("format")
+                .long("format")
+                .short('f')
+                .about("Use this string formatting")
                 .takes_value(true),
-        )
-        .arg(
-            Arg::new("input")
-                .about("Input file")
-                .required(true)
-                .long_about("If not present or a single dash, standard input will be used"),
-        )
-        .arg(
-            Arg::new("match")
-                .about("Count maches for those strings")
-                .required(true)
-                .takes_value(true)
-                .multiple(true),
         );
+    timehist = add_input(add_width(add_regex(add_intervals(timehist))));
 
     App::new("lowcharts")
         .author(clap::crate_authors!())
@@ -136,6 +145,7 @@ pub fn get_app() -> App<'static> {
         .subcommand(hist)
         .subcommand(plot)
         .subcommand(matches)
+        .subcommand(timehist)
 }
 
 #[cfg(test)]
@@ -183,4 +193,32 @@ mod tests {
             assert!(false, "Subcommand `plot` not detected");
         }
     }
+
+    #[test]
+    fn matches_subcommand_arg_parsing() {
+        let arg_vec = vec!["lowcharts", "matches", "-", "A", "B", "C"];
+        let m = get_app().get_matches_from(arg_vec);
+        if let Some(sub_m) = m.subcommand_matches("matches") {
+            assert_eq!("-", sub_m.value_of("input").unwrap());
+            assert_eq!(
+                // vec![String::from("A"), String::from("B"), String::from("C")],
+                vec!["A", "B", "C"],
+                sub_m.values_of("match").unwrap().collect::<Vec<&str>>()
+            );
+        } else {
+            assert!(false, "Subcommand `matches` not detected");
+        }
+    }
+
+    #[test]
+    fn timehist_subcommand_arg_parsing() {
+        let arg_vec = vec!["lowcharts", "timehist", "--regex", "foo", "some"];
+        let m = get_app().get_matches_from(arg_vec);
+        if let Some(sub_m) = m.subcommand_matches("timehist") {
+            assert_eq!("some", sub_m.value_of("input").unwrap());
+            assert_eq!("foo", sub_m.value_of("regex").unwrap());
+        } else {
+            assert!(false, "Subcommand `timehist` not detected");
+        }
+    }
 }