checkpoint: add configurable max pages and max concurrency settings

internal/crawler/crawler.go

@@ -15,9 +15,10 @@ type Crawler struct {
 	mu                 *sync.Mutex
 	concurrencyControl chan struct{}
 	wg                 *sync.WaitGroup
+	maxPages           int
 }
 
-func NewCrawler(rawBaseURL string) (*Crawler, error) {
+func NewCrawler(rawBaseURL string, maxConcurrency, maxPages int) (*Crawler, error) {
 	baseURL, err := url.Parse(rawBaseURL)
 	if err != nil {
 		return nil, fmt.Errorf("unable to parse the base URL: %w", err)
@@ -31,16 +32,15 @@ func NewCrawler(rawBaseURL string) (*Crawler, error) {
 		pages:              make(map[string]int),
 		baseURL:            baseURL,
 		mu:                 &sync.Mutex{},
-		concurrencyControl: make(chan struct{}, 2),
+		concurrencyControl: make(chan struct{}, maxConcurrency),
 		wg:                 &waitGroup,
+		maxPages:           maxPages,
 	}
 
 	return &crawler, nil
 }
 
 func (c *Crawler) Crawl(rawCurrentURL string) {
-	var err error
-
 	// Add an empty struct to channel here
 	c.concurrencyControl <- struct{}{}
 
@@ -51,6 +51,10 @@ func (c *Crawler) Crawl(rawCurrentURL string) {
 		c.wg.Done()
 	}()
 
+	if c.reachedMaxPages() {
+		return
+	}
+
 	// if current URL is not on the same domain as the base URL then return early.
 	hasEqualDomain, err := c.HasEqualDomain(rawCurrentURL)
 	if err != nil {
@@ -147,9 +151,19 @@ func (c *Crawler) Wait() {
 }
 
 func (c *Crawler) PrintReport() {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
 	fmt.Printf("\n\nREPORT:\n")
 
 	for page, count := range maps.All(c.pages) {
 		fmt.Printf("%s: %d\n", page, count)
 	}
 }
+
+func (c *Crawler) reachedMaxPages() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	return len(c.pages) >= c.maxPages
+}

main.go

@@ -1,18 +1,13 @@
 package main
 
 import (
-	"errors"
 	"fmt"
 	"os"
+	"strconv"
 
 	"codeflow.dananglin.me.uk/apollo/web-crawler/internal/crawler"
 )
 
-var (
-	errNoWebsiteProvided = errors.New("no website provided")
-	errTooManyArgs       = errors.New("too many arguments provided")
-)
-
 func main() {
 	if err := run(); err != nil {
 		os.Stderr.WriteString("ERROR: " + err.Error() + "\n")
@@ -24,17 +19,23 @@ func main() {
 func run() error {
 	args := os.Args[1:]
 
-	if len(args) == 0 {
-		return errNoWebsiteProvided
-	}
-
-	if len(args) > 1 {
-		return errTooManyArgs
+	if len(args) != 3 {
+		return fmt.Errorf("unexpected number of arguments received: want 3, got %d", len(args))
 	}
 
 	baseURL := args[0]
 
-	c, err := crawler.NewCrawler(baseURL)
+	maxConcurrency, err := strconv.Atoi(args[1])
+	if err != nil {
+		return fmt.Errorf("unable to convert the max concurrency (%s) to an integer: %w", args[1], err)
+	}
+
+	maxPages, err := strconv.Atoi(args[2])
+	if err != nil {
+		return fmt.Errorf("unable to convert the max pages (%s) to an integer: %w", args[2], err)
+	}
+
+	c, err := crawler.NewCrawler(baseURL, maxConcurrency, maxPages)
 	if err != nil {
 		return fmt.Errorf("unable to create the crawler: %w", err)
 	}