Cargo.lock

@@ -220,6 +220,17 @@ dependencies = [
  "event-listener",
 ]
 
+[[package]]
+name = "async-recursion"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2cda8f4bcc10624c4e85bc66b3f452cca98cfa5ca002dc83a16aad2367641bea"
+dependencies = [
+ "proc-macro2 1.0.37",
+ "quote 1.0.18",
+ "syn 1.0.92",
+]
+
 [[package]]
 name = "async-trait"
 version = "0.1.53"
@@ -560,6 +571,17 @@ dependencies = [
  "syn 1.0.92",
 ]
 
+[[package]]
+name = "derive-new"
+version = "0.5.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3418329ca0ad70234b9735dc4ceed10af4df60eff9c8e7b06cb5e520d92c3535"
+dependencies = [
+ "proc-macro2 1.0.37",
+ "quote 1.0.18",
+ "syn 1.0.92",
+]
+
 [[package]]
 name = "derive_more"
 version = "0.99.17"
@@ -1295,9 +1317,12 @@ name = "lemmy-stats-crawler"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "async-recursion",
  "clap",
+ "derive-new",
  "futures",
  "lemmy_api_common",
+ "log",
  "once_cell",
  "reqwest",
  "semver",

Cargo.toml

@@ -15,3 +15,6 @@ clap = "3.1.15"
 semver = "1.0.9"
 once_cell = "1.10.0"
 lemmy_api_common = "0.16.0"
+async-recursion = "1.0.0"
+log = "0.4.17"
+derive-new = "0.5.9"

src/crawl.rs

@@ -1,66 +1,16 @@
+use crate::CLIENT;
 use crate::REQUEST_TIMEOUT;
-use anyhow::anyhow;
 use anyhow::Error;
+use async_recursion::async_recursion;
+use futures::future::join_all;
 use lemmy_api_common::site::GetSiteResponse;
-use once_cell::sync::Lazy;
-use reqwest::Client;
+use log::info;
 use semver::Version;
 use serde::Serialize;
-use std::collections::VecDeque;
-
-static CLIENT: Lazy<Client> = Lazy::new(Client::default);
-
-pub async fn crawl(
-    start_instances: Vec<String>,
-    exclude: Vec<String>,
-    max_depth: i32,
-) -> Result<(Vec<InstanceDetails>, i32), Error> {
-    let mut pending_instances: VecDeque<CrawlInstance> = start_instances
-        .iter()
-        .map(|s| CrawlInstance::new(s.to_string(), 0))
-        .collect();
-    let min_lemmy_version = min_lemmy_version().await?;
-    let mut crawled_instances = vec![];
-    let mut instance_details = vec![];
-    let mut failed_instances = 0;
-    while let Some(current_instance) = pending_instances.pop_back() {
-        crawled_instances.push(current_instance.domain.clone());
-        if current_instance.depth > max_depth || exclude.contains(&current_instance.domain) {
-            continue;
-        }
-        match fetch_instance_details(&current_instance.domain, &min_lemmy_version).await {
-            Ok(details) => {
-                if let Some(federated) = &details.site_info.federated_instances.as_ref() {
-                    for i in &federated.linked {
-                        let is_in_crawled = crawled_instances.contains(i);
-                        let is_in_pending = pending_instances.iter().any(|p| &p.domain == i);
-                        if !is_in_crawled && !is_in_pending {
-                            let ci = CrawlInstance::new(i.clone(), current_instance.depth + 1);
-                            pending_instances.push_back(ci);
-                        }
-                    }
-                }
-                instance_details.push(details);
-            }
-            Err(e) => {
-                failed_instances += 1;
-                eprintln!("Failed to crawl {}: {}", current_instance.domain, e)
-            }
-        }
-    }
-
-    // Sort by active monthly users descending
-    instance_details.sort_by_key(|i| {
-        i.site_info
-            .site_view
-            .as_ref()
-            .map(|s| s.counts.users_active_month)
-            .unwrap_or(0)
-    });
-    instance_details.reverse();
-
-    Ok((instance_details, failed_instances))
-}
+use std::collections::HashSet;
+use std::ops::Deref;
+use std::sync::Arc;
+use tokio::sync::Mutex;
 
 #[derive(Serialize, Debug)]
 pub struct InstanceDetails {
@@ -68,25 +18,43 @@ pub struct InstanceDetails {
     pub site_info: GetSiteResponse,
 }
 
-struct CrawlInstance {
+#[derive(new)]
+pub struct CrawlParams {
+    min_lemmy_version: Version,
+    exclude_domains: Vec<String>,
+    max_depth: i32,
+    crawled_instances: Arc<Mutex<HashSet<String>>>,
+}
+
+#[derive(new)]
+pub struct CrawlJob {
     domain: String,
-    depth: i32,
+    current_depth: i32,
+    params: Arc<CrawlParams>,
 }
 
-impl CrawlInstance {
-    pub fn new(domain: String, depth: i32) -> CrawlInstance {
-        CrawlInstance { domain, depth }
+impl CrawlJob {
+    #[async_recursion]
+    pub async fn crawl(self) -> Result<Vec<Result<InstanceDetails, Error>>, Error> {
+        // need to acquire and release mutix before recursing, otherwise it will deadlock
+        {
+            let mut crawled_instances = self.params.crawled_instances.deref().lock().await;
+            if crawled_instances.contains(&self.domain) {
+                return Ok(vec![]);
+            } else {
+                crawled_instances.insert(self.domain.clone());
             }
         }
 
-async fn fetch_instance_details(
-    domain: &str,
-    min_lemmy_version: &Version,
-) -> Result<InstanceDetails, Error> {
-    let client = Client::default();
+        if self.current_depth > self.params.max_depth
+            || self.params.exclude_domains.contains(&self.domain)
+        {
+            return Ok(vec![]);
+        }
+        info!("Starting crawl for {}", &self.domain);
 
-    let site_info_url = format!("https://{}/api/v3/site", domain);
-    let site_info = client
+        let site_info_url = format!("https://{}/api/v3/site", &self.domain);
+        let site_info = CLIENT
             .get(&site_info_url)
             .timeout(REQUEST_TIMEOUT)
             .send()
@@ -95,27 +63,31 @@ async fn fetch_instance_details(
             .await?;
 
         let version = Version::parse(&site_info.version)?;
-    if &version < min_lemmy_version {
-        return Err(anyhow!("lemmy version is too old ({})", version));
+        if version < self.params.min_lemmy_version {
+            return Ok(vec![]);
         }
 
-    Ok(InstanceDetails {
-        domain: domain.to_owned(),
+        let mut result = vec![];
+        if let Some(federated) = &site_info.federated_instances {
+            for domain in federated.linked.iter() {
+                let crawl_job =
+                    CrawlJob::new(domain.clone(), self.current_depth + 1, self.params.clone());
+                result.push(crawl_job.crawl());
+            }
+        }
+
+        let mut result2: Vec<Result<InstanceDetails, Error>> = join_all(result)
+            .await
+            .into_iter()
+            .filter_map(|r| r.ok())
+            .flat_map(|r| r.into_iter())
+            .collect();
+        info!("Successfully finished crawl for {}", &self.domain);
+        result2.push(Ok(InstanceDetails {
+            domain: self.domain,
             site_info,
-    })
-}
+        }));
 
-/// calculate minimum allowed lemmy version based on current version. in case of current version
-/// 0.16.3, the minimum from this function is 0.15.3. this is to avoid rejecting all instances on
-/// the previous version when a major lemmy release is published.
-async fn min_lemmy_version() -> Result<Version, Error> {
-    let lemmy_version_url = "https://raw.githubusercontent.com/LemmyNet/lemmy-ansible/main/VERSION";
-    let req = CLIENT
-        .get(lemmy_version_url)
-        .timeout(REQUEST_TIMEOUT)
-        .send()
-        .await?;
-    let mut version = Version::parse(req.text().await?.trim())?;
-    version.minor -= 1;
-    Ok(version)
+        Ok(result2)
+    }
 }

src/defaults.rs

@@ -0,0 +1,4 @@
+pub const DEFAULT_START_INSTANCES: &str = "lemmy.ml";
+pub const DEFAULT_MAX_CRAWL_DEPTH: &str = "20";
+pub const EXCLUDE_INSTANCES: &str =
+    "ds9.lemmy.ml, enterprise.lemmy.ml, voyager.lemmy.ml, test.lemmy.ml";

src/lib.rs

@@ -1,9 +1,74 @@
+#[macro_use]
+extern crate derive_new;
+
+use crate::crawl::{CrawlJob, CrawlParams, InstanceDetails};
+use anyhow::Error;
+use futures::future::join_all;
+use once_cell::sync::Lazy;
+use reqwest::Client;
+use semver::Version;
+use std::collections::HashSet;
+use std::sync::Arc;
 use std::time::Duration;
+use tokio::sync::Mutex;
 
 pub mod crawl;
+pub mod defaults;
 
 pub const REQUEST_TIMEOUT: Duration = Duration::from_secs(10);
-pub const DEFAULT_START_INSTANCES: &str = "lemmy.ml";
-pub const DEFAULT_MAX_CRAWL_DEPTH: &str = "20";
-pub const EXCLUDE_INSTANCES: &str =
-    "ds9.lemmy.ml, enterprise.lemmy.ml, voyager.lemmy.ml, test.lemmy.ml";
+
+static CLIENT: Lazy<Client> = Lazy::new(Client::default);
+
+pub async fn start_crawl(
+    start_instances: Vec<String>,
+    exclude_domains: Vec<String>,
+    max_depth: i32,
+) -> Result<Vec<InstanceDetails>, Error> {
+    let params = Arc::new(CrawlParams::new(
+        min_lemmy_version().await?,
+        exclude_domains,
+        max_depth,
+        Arc::new(Mutex::new(HashSet::new())),
+    ));
+    let mut jobs = vec![];
+    for domain in start_instances.into_iter() {
+        let job = CrawlJob::new(domain, 0, params.clone());
+        jobs.push(job.crawl());
+    }
+
+    // TODO: optionally log the errors
+    let mut instance_details: Vec<InstanceDetails> = join_all(jobs)
+        .await
+        .into_iter()
+        .filter_map(|r| r.ok())
+        .flat_map(|r| r.into_iter())
+        .filter_map(|r| r.ok())
+        .collect();
+
+    // Sort by active monthly users descending
+    instance_details.sort_unstable_by_key(|i| {
+        i.site_info
+            .site_view
+            .as_ref()
+            .map(|s| s.counts.users_active_month)
+            .unwrap_or(0)
+    });
+    instance_details.reverse();
+
+    Ok(instance_details)
+}
+
+/// calculate minimum allowed lemmy version based on current version. in case of current version
+/// 0.16.3, the minimum from this function is 0.15.3. this is to avoid rejecting all instances on
+/// the previous version when a major lemmy release is published.
+async fn min_lemmy_version() -> Result<Version, Error> {
+    let lemmy_version_url = "https://raw.githubusercontent.com/LemmyNet/lemmy-ansible/main/VERSION";
+    let req = CLIENT
+        .get(lemmy_version_url)
+        .timeout(REQUEST_TIMEOUT)
+        .send()
+        .await?;
+    let mut version = Version::parse(req.text().await?.trim())?;
+    version.minor -= 1;
+    Ok(version)
+}

src/main.rs

@@ -1,7 +1,10 @@
 use anyhow::Error;
 use clap::{Arg, Command};
-use lemmy_stats_crawler::crawl::{crawl, InstanceDetails};
-use lemmy_stats_crawler::{DEFAULT_MAX_CRAWL_DEPTH, DEFAULT_START_INSTANCES, EXCLUDE_INSTANCES};
+use lemmy_stats_crawler::crawl::InstanceDetails;
+use lemmy_stats_crawler::defaults::{
+    DEFAULT_MAX_CRAWL_DEPTH, DEFAULT_START_INSTANCES, EXCLUDE_INSTANCES,
+};
+use lemmy_stats_crawler::start_crawl;
 use serde::Serialize;
 
 #[tokio::main]
@@ -37,9 +40,8 @@ pub async fn main() -> Result<(), Error> {
         .parse()?;
 
     eprintln!("Crawling...");
-    let (instance_details, failed_instances) =
-        crawl(start_instances, exclude, max_crawl_depth).await?;
-    let total_stats = aggregate(instance_details, failed_instances);
+    let instance_details = start_crawl(start_instances, exclude, max_crawl_depth).await?;
+    let total_stats = aggregate(instance_details);
 
     println!("{}", serde_json::to_string_pretty(&total_stats)?);
     Ok(())
@@ -48,7 +50,6 @@ pub async fn main() -> Result<(), Error> {
 #[derive(Serialize)]
 struct TotalStats {
     crawled_instances: i32,
-    failed_instances: i32,
     online_users: usize,
     total_users: i64,
     users_active_day: i64,
@@ -58,7 +59,7 @@ struct TotalStats {
     instance_details: Vec<InstanceDetails>,
 }
 
-fn aggregate(instance_details: Vec<InstanceDetails>, failed_instances: i32) -> TotalStats {
+fn aggregate(instance_details: Vec<InstanceDetails>) -> TotalStats {
     let mut online_users = 0;
     let mut total_users = 0;
     let mut users_active_day = 0;
@@ -79,7 +80,6 @@ fn aggregate(instance_details: Vec<InstanceDetails>, failed_instances: i32) -> T
     }
     TotalStats {
         crawled_instances,
-        failed_instances,
         online_users,
         total_users,
         users_active_day,