added current code

src/bin/generate_benchmark_targets.rs

@@ -0,0 +1,74 @@
+use fapra_osm_2::gridgraph::GridGraph;
+use std::fs::File;
+use clap::Parser;
+use std::process::exit;
+use rand::seq::SliceRandom;
+use fapra_osm_2::utils::RoutingQuery;
+use serde_json;
+
+#[derive(Parser, Debug)]
+#[clap(author, version, about, long_about=None)]
+struct Args {
+    /// name of the FMI file to read
+    #[clap(short, long)]
+    graph: String,
+
+    /// number of samples to generate
+    #[clap(short, long, default_value_t = 1000)]
+    samples: usize,
+}
+
+fn main() {
+    let args = Args::parse();
+
+    let file = match File::open(args.graph.clone()) {
+        Ok(f) => f,
+        Err(e) => {
+            println!("Error while opening the file {}: {}", args.graph, e);
+            exit(1)
+        }
+    };
+
+    let graph = match GridGraph::from_fmi_file(file) {
+        Ok(g) => g,
+        Err(e) => {
+            println!("Error while reading the graph: {:?}", e);
+            exit(1);
+        }
+    };
+
+    let mut rng = rand::thread_rng();
+
+    let mut targets = graph.nodes.choose_multiple(&mut rng, args.samples * 2);
+
+    let mut queries: Vec<RoutingQuery> = Vec::new();
+
+    for i in (0..targets.len()).step_by(2) {
+
+        let source = match targets.next() {
+            Some(t) => t.index as usize,
+            None => {
+                println!("Expected a source node with index {}, but there was None.", i);
+                exit(2);
+            },
+        };
+
+        let destination = match targets.next() {
+            Some(t) => t.index as usize,
+            None => {
+                println!("Expected a destination node with index {}, but there was None.", i+1);
+                exit(2);
+            },
+        };
+
+        queries.push(RoutingQuery{ source, destination})
+    }
+
+    match serde_json::to_string(&queries) {
+        Ok(s) => println!("{}", s),
+        Err(e) => {
+            println!("Error while serializeing: {}", e);
+            exit(2);
+        }
+    };
+}