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The built-in AS list had no letter outside ASCII, and make asupdate rejected today's as.csv, which added a country code column. The generator now checks only the first three header columns and reads past the rest; the parsing moved into parseCSV. The list is regenerated. The new source spells some names differently and no longer lists AS 0 or the documentation AS numbers, so the tests that relied on those entries changed. A WHOIS answer that is not valid UTF-8 is now decoded as Latin-1, which RIPE and APNIC send, before it is parsed and stored. LACNIC answers in UTF-8. Model: opus-5-5
131 lines
3.0 KiB
Go
131 lines
3.0 KiB
Go
// Package main generates the embedded AS info data for the asinfo package
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package main
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import (
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"context"
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"encoding/csv"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"log"
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"net/http"
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"os"
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"strconv"
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"strings"
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)
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const asCsvURL = "https://github.com/ipverse/asn-info/raw/refs/heads/master/as.csv"
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// The first columns of as.csv, the ones the generator reads. It reads past
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// the columns after them, such as the country code.
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const (
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asnColumn = "asn"
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handleColumn = "handle"
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descriptionColumn = "description"
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columnsRead = 3
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)
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var errUnexpectedHeader = errors.New("unexpected CSV header")
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// ASInfo represents information about an Autonomous System
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type ASInfo struct {
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ASN int `json:"asn"`
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Handle string `json:"handle"`
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Description string `json:"description"`
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}
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func main() {
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// Configure logger to write to stderr
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log.SetOutput(os.Stderr)
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// Fetch the CSV data
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log.Println("Fetching AS CSV data...")
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req, err := http.NewRequestWithContext(
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context.Background(), http.MethodGet, asCsvURL, nil)
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if err != nil {
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log.Fatalf("Failed to fetch CSV: %v", err)
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}
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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log.Fatalf("Failed to fetch CSV: %v", err)
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}
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if resp.StatusCode != http.StatusOK {
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log.Fatalf("Failed to fetch CSV: HTTP %d", resp.StatusCode)
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}
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asInfos, err := parseCSV(resp.Body)
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// Closed here rather than deferred: log.Fatalf exits without running
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// deferred calls.
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_ = resp.Body.Close()
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if err != nil {
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log.Fatalf("Failed to parse CSV: %v", err)
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}
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log.Printf("Parsed %d AS records", len(asInfos))
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// Convert to JSON and output to stdout
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encoder := json.NewEncoder(os.Stdout)
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encoder.SetIndent("", "\t")
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err = encoder.Encode(asInfos)
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if err != nil {
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log.Fatalf("Failed to encode JSON: %v", err)
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}
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}
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// parseCSV reads as.csv from r and returns its ASes, with the handle and the
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// description as the file spells them. A header whose first columns are not
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// the AS number, the handle and the description is an error. A record that
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// does not parse is logged and skipped.
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func parseCSV(r io.Reader) ([]ASInfo, error) {
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reader := csv.NewReader(r)
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header, err := reader.Read()
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if err != nil {
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return nil, fmt.Errorf("read CSV header: %w", err)
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}
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if len(header) < columnsRead || header[0] != asnColumn ||
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header[1] != handleColumn || header[2] != descriptionColumn {
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return nil, fmt.Errorf("%w: %v", errUnexpectedHeader, header)
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}
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var asInfos []ASInfo
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for {
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// The reader returns an error for a record with a different number
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// of fields than the header.
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record, err := reader.Read()
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if errors.Is(err, io.EOF) {
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break
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}
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if err != nil {
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log.Printf("Error reading CSV record: %v", err)
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continue
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}
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asn, err := strconv.Atoi(record[0])
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if err != nil {
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log.Printf("Invalid ASN %q: %v", record[0], err)
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continue
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}
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asInfos = append(asInfos, ASInfo{
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ASN: asn,
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Handle: strings.TrimSpace(record[1]),
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Description: strings.TrimSpace(record[2]),
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})
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}
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return asInfos, nil
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}
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