handle checking for file better

README.md

@@ -40,14 +40,18 @@ $EDITOR Crawler.toml
 - [x] Allow for storing asynchronously - dropping the "links to" logic fixes this need
 - [x] Control crawler via config file (no recompliation needed)
 
-3/17/25: Took >1hr to crawl 100 pages
+### Feats
 
-3/19/25: Took 20min to crawl 1000 pages
+3/17/25: Took >1hr to crawl 100 pages.
+
+3/19/25: Took 20min to crawl 1000 pages.
 This ment we stored 1000 pages, 142,997 urls, and 1,425,798 links between the two.
 
-3/20/25: Took 5min to crawl 1000 pages
+3/20/25: Took 5min to crawl 1000 pages.
 
-3/21/25: Took 3min to crawl 1000 pages
+3/21/25: Took 3min to crawl 1000 pages.
+
+7/.../25: Downloaded just shy of 12TB of data from a remote server.
 
 # About
 

src/db.rs

@@ -102,7 +102,7 @@ pub async fn get_next(db: &Surreal<Client>, config: &Config) -> Option<Website>
             Ok(ok) => ok,
             Err(_err) => {
                 // basically just CSMA/CA
-                let delay = rand::random_range(10..500);
+                let delay = rand::random_range(10..10_000);
                 sleep(Duration::from_millis(delay)).await;
                 fails += 1;
                 // Don't get stuck here forever, failing...
@@ -146,9 +146,9 @@ pub async fn connect(config: &Config) -> surrealdb::Result<Surreal<Client>> {
         .await?;
 
     let setup = include_bytes!("setup.surql");
-    let file = setup.iter().map(|c| *c as char).collect::<String>();
+    let init_commands = setup.iter().map(|c| *c as char).collect::<String>();
 
-    db.query(file)
+    db.query(init_commands)
         .await
         .expect("Failed to setup surreal tables.");
 

src/filesystem.rs

@@ -34,10 +34,38 @@ pub fn as_path(url: &Url, content_type: &HeaderValue) -> PathBuf {
     url_path
 }
 
+pub async fn check_file_length(file: &PathBuf) -> Option<u64> {
+    match tokio::fs::OpenOptions::new()
+        .write(false)
+        .read(true)
+        .create(false)
+        .open(file).await
+    {
+        Ok(file) => {
+            match file.metadata().await {
+                Ok(meta) => {
+                    return Some(meta.len())
+                },
+                Err(err) => {
+                    error!("Failed to get metadata. {}", err)
+                },
+            }
+        },
+        Err(err) => {
+            match err.kind() {
+                ErrorKind::NotFound => {/* ignore */},
+                _ => warn!("Failed to open file to check length. {:?} {}", file, err),
+            }
+        },
+    }
+    None
+
+}
+
 pub async fn init(filename: &PathBuf) -> Option<fs::File> {
     let file = async || tokio::fs::OpenOptions::new()
         .write(true)
-        .append(true)
+        .append(false)
         .create(true)
         .open(&filename).await;
 

src/main.rs

@@ -5,17 +5,27 @@
 extern crate html5ever;
 
 use std::{
-    collections::HashSet, fs::File, io::Read, sync::{Arc, LazyLock}
+    collections::HashSet,
+    fs::File,
+    io::Read,
+    sync::{Arc, LazyLock},
 };
 
-use futures_util::StreamExt;
-use opentelemetry::{global::{self}, metrics::{Counter, Meter, UpDownCounter}};
-use opentelemetry_otlp::{Protocol, WithExportConfig};
 use db::{connect, Website};
+use futures_util::StreamExt;
+use opentelemetry::{
+    global::{self},
+    metrics::{Counter, Meter, UpDownCounter},
+};
+use opentelemetry_otlp::{Protocol, WithExportConfig};
 use opentelemetry_sdk::{metrics::SdkMeterProvider, trace::SdkTracerProvider};
 use serde::Deserialize;
 use surrealdb::{engine::remote::ws::Client, Surreal};
-use tokio::{io::{AsyncWriteExt, BufWriter}, sync::RwLock, task::JoinSet};
+use tokio::{
+    io::{AsyncReadExt, AsyncWriteExt, BufWriter},
+    sync::RwLock,
+    task::JoinSet,
+};
 use tracing::{debug, error, info, instrument, level_filters::LevelFilter, trace, warn};
 use tracing_subscriber::{fmt, layer::SubscriberExt, EnvFilter, Layer, Registry};
 
@@ -26,36 +36,29 @@ mod filesystem;
 mod parser;
 
 static METER: LazyLock<Meter> = LazyLock::new(|| global::meter("Internet_Mapper"));
-static BEING_PROCESSED: LazyLock<UpDownCounter<i64>> = LazyLock::new(||
+static BATCH_SIZE: LazyLock<Counter<u64>> =
+    LazyLock::new(|| METER.u64_counter("crawler_batch_size").build());
+static BEING_PROCESSED: LazyLock<UpDownCounter<i64>> = LazyLock::new(|| {
     METER
         .i64_up_down_counter("crawler_pages_being_processed")
         .build()
-);
+});
-static BEING_PARSED: LazyLock<UpDownCounter<i64>> = LazyLock::new(||
+static BEING_PARSED: LazyLock<UpDownCounter<i64>> = LazyLock::new(|| {
     METER
         .i64_up_down_counter("crawler_pages_being_parsed")
         .build()
-);
+});
-static BEING_STREAMED: LazyLock<UpDownCounter<i64>> = LazyLock::new(|| 
+static BEING_STREAMED: LazyLock<UpDownCounter<i64>> = LazyLock::new(|| {
     METER
         .i64_up_down_counter("crawler_pages_being_streamed")
         .build()
-);
+});
-static GET_IN_FLIGHT: LazyLock<UpDownCounter<i64>> = LazyLock::new(|| 
+static GET_IN_FLIGHT: LazyLock<UpDownCounter<i64>> =
-    METER
+    LazyLock::new(|| METER.i64_up_down_counter("crawler_gets_in_flight").build());
-        .i64_up_down_counter("crawler_gets_in_flight")
+static TOTAL_BYTES_DOWN: LazyLock<Counter<u64>> =
-        .build()
+    LazyLock::new(|| METER.u64_counter("crawler_total_bytes_down").build());
-);
+static SITES_CRAWLED: LazyLock<Counter<u64>> =
-static TOTAL_BYTES_DOWN: LazyLock<Counter<u64>> = LazyLock::new(|| 
+    LazyLock::new(|| METER.u64_counter("crawler_total_sites_crawled").build());
-    METER
-        .u64_counter("crawler_total_bytes_down")
-        .build()
-);
-static SITES_CRAWLED: LazyLock<Counter<u64>> = LazyLock::new(|| 
-    METER
-        .u64_counter("crawler_total_sites_crawled")
-        .build()
-);
 
 static CONFIG: LazyLock<Config> = LazyLock::new(|| {
     let mut file = File::open("./Crawler.toml").expect("Failed to read Crawler.toml");
@@ -96,6 +99,8 @@ async fn main() {
     global::set_tracer_provider(load_tracing(&CONFIG));
     global::set_meter_provider(load_metrics(&CONFIG));
 
+    BATCH_SIZE.add(CONFIG.batch_size as u64, &[]);
+
     // When getting uncrawled pages, name must contain this variable. "" will effectively get ignored.
     // let crawl_filter = "en.wikipedia.org/";
     // let budget = 50;
@@ -123,15 +128,40 @@ async fn main() {
     // let mut main_loop_span= TRACER.start("Main-Loop");
     let mut futures = JoinSet::new();
     for _ in 0..CONFIG.batch_size {
-        futures.spawn(process_single_thread(&CONFIG, db.clone(), reqwest.clone(), crawled.clone()));
+        futures.spawn(process_single_thread(
+            &CONFIG,
+            db.clone(),
+            reqwest.clone(),
+            crawled.clone(),
+        ));
     }
+
+    while let Some(_) = futures.join_next().await {
+        // Budget - Threads - This thread (1)
+        // Would roughly be the acceptable amount at which a thread should exit
+        if *(crawled.read().await) < CONFIG.budget - CONFIG.batch_size - 1 {
+            warn!("Thread terminated early, restarting");
+            futures.spawn(process_single_thread(
+                &CONFIG,
+                db.clone(),
+                reqwest.clone(),
+                crawled.clone(),
+            ));
+        }
+    }
+
     futures.join_all().await;
     // main_loop_span.end();
 
     info!("Done");
 }
 
-async fn process_single_thread(config: &Config, db: Surreal<Client>, reqwest: reqwest::Client, crawled: Arc<RwLock<usize>>) {
+async fn process_single_thread(
+    config: &Config,
+    db: Surreal<Client>,
+    reqwest: reqwest::Client,
+    crawled: Arc<RwLock<usize>>,
+) {
     while *(crawled.read().await) < config.budget {
         let uncrawled = get_next(&db.clone(), &config).await;
         match uncrawled {
@@ -141,11 +171,11 @@ async fn process_single_thread(config: &Config, db: Surreal<Client>, reqwest: re
                 // Somehow this write doesn't hang on the while's read?
                 let mut c = crawled.write().await;
                 *c += 1;
-            },
+            }
             None => {
                 warn!("fn::get_next() returned None");
                 return;
-            },
+            }
         }
     }
 }
@@ -154,7 +184,6 @@ async fn process_single_thread(config: &Config, db: Surreal<Client>, reqwest: re
 /// Downloads and crawls and stores a webpage.
 /// It is acceptable to clone `db`, `reqwest`, and `s3` because they all use `Arc`s internally. - Noted by Oliver
 async fn process(mut site: Website, db: Surreal<Client>, reqwest: reqwest::Client) {
-
     // METRICS
     debug!(url = &site.site.as_str(), "Process: {}", &site.site);
     BEING_PROCESSED.add(1, &[]);
@@ -166,6 +195,8 @@ async fn process(mut site: Website, db: Surreal<Client>, reqwest: reqwest::Clien
     // Send the http request (get)
     GET_IN_FLIGHT.add(1, &[]);
     if let Ok(response) = request_builder.send().await {
+        let mut skip_download = false;
+
         GET_IN_FLIGHT.add(-1, &[]);
 
         let headers = response.headers();
@@ -180,33 +211,76 @@ async fn process(mut site: Website, db: Surreal<Client>, reqwest: reqwest::Clien
 
         let ct = match (CT, ct) {
             (None, None) => {
-                warn!("Server did not respond with Content-Type header. Url: {} Headers: ({:?})", site.site.to_string(), headers);
+                warn!(
-                return
+                    "Server did not respond with Content-Type header. Url: {} Headers: ({:?})",
-            },
+                    site.site.to_string(),
+                    headers
+                );
+                return;
+            }
             (None, Some(a)) => a,
             (Some(a), None) => a,
             (Some(a), Some(_)) => a,
         };
 
         // create filepath (handles / -> /index.html)
-        let path = filesystem::as_path(&site.site, ct);
+        let real_path = filesystem::as_path(&site.site, ct);
-        let mut tmp_path= path.clone();
+        let mut tmp_path = real_path.clone();
         if !(tmp_path.add_extension("crawl_temp")) {
             warn!("Failed to add extension to file");
             // fallback ig
             tmp_path = tmp_path.with_extension("crawl_temp");
         }
 
+        // CODE FOR UPDATING DOWNLOADED CONTENT:
+        // Check the Content-Length header (we assume the server is telling the truth) (I don't see
+        // a reason for it to lie in this case).
+        // And see if the file on the disk is the same length.
+        // Yes, technically this isn't perfect, but the other option is storing ETags, which I
+        // don't want to do right now.
+        if let Some(len) = headers.get("Content-Length") {
+            if let Ok(s) = len.to_str() {
+                // length is in bytes
+                if let Ok(len) = s.parse::<u64>() {
+                    if let Some(disk_len) = filesystem::check_file_length(&real_path).await {
+                        if disk_len == len {
+                            skip_download = true;
+                        }
+                    } else {
+                        // File not found (or other error).
+                        // Program will continue on it's way, downloading content.
+                    }
+                }
+            }
+        }
+
         // make sure that the file is good to go
         if let Some(file) = filesystem::init(&tmp_path).await {
             // Get body from response
             // stream the response onto the disk
             let mut stream = response.bytes_stream();
 
-            let should_parse = path.to_string_lossy().ends_with(".html");
+            let should_parse = real_path.to_string_lossy().ends_with(".html");
-            let mut writer = BufWriter::new(file);
+
             let mut buf: Vec<u8> = Vec::new();
 
+            if skip_download && should_parse {
+                // since we are skipping the download we will just read the file off the disk to
+                // parse it
+                if let Ok(mut file) = tokio::fs::OpenOptions::new() 
+                    .read(true)
+                    .open(&real_path).await
+                {
+                    if let Err(err) = file.read_to_end(&mut buf).await {
+                        warn!("Failed to read file off disk for parsing, {}", err);
+                    }
+                }
+            } 
+
+            // !!!DOWNLOADING TIME!!!
+            if !skip_download {
+                let mut writer = BufWriter::new(file);
+
                 // Write file to disk
                 trace!("Writing at: {:?}", tmp_path);
                 BEING_STREAMED.add(1, &[]);
@@ -222,18 +296,18 @@ async fn process(mut site: Website, db: Surreal<Client>, reqwest: reqwest::Clien
                             if should_parse {
                                 data.iter().for_each(|f| buf.push(*f));
                             }
-                    },
+                        }
                         Err(err) => {
                             error!("{err}")
-                    },
+                        }
                     }
                 }
                 let _ = writer.flush().await;
                 // rename the temp file into the real file name
-            if let Err(err) = tokio::fs::rename(&tmp_path, &path).await {
+                if let Err(err) = tokio::fs::rename(&tmp_path, &real_path).await {
                     error!(
                         from = &*tmp_path.to_string_lossy(),
-                    to = &*path.to_string_lossy(),
+                        to = &*real_path.to_string_lossy(),
                         "Error renaming file: {}",
                         err
                     );
@@ -241,6 +315,7 @@ async fn process(mut site: Website, db: Surreal<Client>, reqwest: reqwest::Clien
 
                 // stream_span.end();
                 BEING_STREAMED.add(-1, &[]);
+            }
 
             // (If needed) Parse the file
             if should_parse {
@@ -319,7 +394,7 @@ fn load_logging(config: &Config) {
             .with_file(true)
             .json()
             .with_writer(writer)
-            .with_filter(filter)
+            .with_filter(filter),
     );
 
     tracing::subscriber::set_global_default(registry).expect("Failed to set default subscriber");
@@ -338,5 +413,3 @@ fn load_metrics(config: &Config) -> SdkMeterProvider {
         .build();
     metrics_provider
 }
-
-

src/setup.surql

@@ -14,3 +14,5 @@ DEFINE FUNCTION OVERWRITE fn::get_next($filter: string) {
     UPDATE $site.id SET processing = true;
     RETURN $site
 };
+
+UPDATE website SET processing = false WHERE processing = true;