Merge pull request #413 from csaf-poc/downloader-interval

Downloader: Make time range configurable to download advisories from

cmd/csaf_aggregator/mirror.go

@@ -76,8 +76,7 @@ func (w *worker) mirrorInternal() (*csaf.AggregatorCSAFProvider, error) {
 		w.client,
 		w.expr,
 		w.metadataProvider,
-		base,
-		nil)
+		base)
 
 	if err := afp.Process(w.mirrorFiles); err != nil {
 		return nil, err

cmd/csaf_downloader/config.go

@@ -11,6 +11,7 @@ package main
 import (
 	"net/http"
 
+	"github.com/csaf-poc/csaf_distribution/v2/internal/models"
 	"github.com/csaf-poc/csaf_distribution/v2/internal/options"
 )
 
@@ -27,6 +28,7 @@ type config struct {
 	Verbose              bool              `long:"verbose" short:"v" description:"Verbose output" toml:"verbose"`
 	Rate                 *float64          `long:"rate" short:"r" description:"The average upper limit of https operations per second (defaults to unlimited)" toml:"rate"`
 	Worker               int               `long:"worker" short:"w" description:"NUMber of concurrent downloads" value-name:"NUM" toml:"worker"`
+	Range                *models.TimeRange `long:"timerange" short:"t" description:"RANGE of time from which advisories to download" value-name:"RANGE" toml:"timerange"`
 
 	ExtraHeader http.Header `long:"header" short:"H" description:"One or more extra HTTP header fields" toml:"header"`
 

cmd/csaf_downloader/downloader.go

@@ -150,8 +150,12 @@ func (d *downloader) download(ctx context.Context, domain string) error {
 		client,
 		d.eval,
 		lpmd.Document,
-		base,
-		nil)
+		base)
+
+	// Do we need time range based filtering?
+	if d.cfg.Range != nil {
+		afp.AgeAccept = d.cfg.Range.Contains
+	}
 
 	return afp.Process(func(label csaf.TLPLabel, files []csaf.AdvisoryFile) error {
 		return d.downloadFiles(ctx, label, files)

csaf/advisories.go

@@ -9,11 +9,14 @@
 package csaf
 
 import (
-	"bufio"
+	"encoding/csv"
+	"fmt"
+	"io"
 	"log"
 	"net/http"
 	"net/url"
 	"strings"
+	"time"
 
 	"github.com/csaf-poc/csaf_distribution/v2/util"
 )
@@ -71,11 +74,12 @@ func (haf HashedAdvisoryFile) SignURL() string { return haf.name(3, ".asc") }
 // AdvisoryFileProcessor implements the extraction of
 // advisory file names from a given provider metadata.
 type AdvisoryFileProcessor struct {
+	AgeAccept func(time.Time) bool
+	Log       func(format string, args ...any)
 	client    util.Client
 	expr      *util.PathEval
 	doc       any
 	base      *url.URL
-	log    func(format string, args ...any)
 }
 
 // NewAdvisoryFileProcessor constructs an filename extractor
@@ -85,14 +89,12 @@ func NewAdvisoryFileProcessor(
 	expr *util.PathEval,
 	doc any,
 	base *url.URL,
-	log func(format string, args ...any),
 ) *AdvisoryFileProcessor {
 	return &AdvisoryFileProcessor{
 		client: client,
 		expr:   expr,
 		doc:    doc,
 		base:   base,
-		log:    log,
 	}
 }
 
@@ -111,7 +113,7 @@ func empty(arr []string) bool {
 func (afp *AdvisoryFileProcessor) Process(
 	fn func(TLPLabel, []AdvisoryFile) error,
 ) error {
-	lg := afp.log
+	lg := afp.Log
 	if lg == nil {
 		lg = func(format string, args ...any) {
 			log.Printf("AdvisoryFileProcessor.Process: "+format, args...)
@@ -173,7 +175,8 @@ func (afp *AdvisoryFileProcessor) Process(
 				continue
 			}
 
-			files, err := afp.loadIndex(base, lg)
+			// Use changes.csv to be able to filter by age.
+			files, err := afp.loadChanges(base, lg)
 			if err != nil {
 				return err
 			}
@@ -186,9 +189,9 @@ func (afp *AdvisoryFileProcessor) Process(
 	return nil
 }
 
-// loadIndex loads baseURL/index.txt and returns a list of files
+// loadChanges loads baseURL/changes.csv and returns a list of files
 // prefixed by baseURL/.
-func (afp *AdvisoryFileProcessor) loadIndex(
+func (afp *AdvisoryFileProcessor) loadChanges(
 	baseURL string,
 	lg func(string, ...any),
 ) ([]AdvisoryFile, error) {
@@ -197,29 +200,53 @@ func (afp *AdvisoryFileProcessor) loadIndex(
 	if err != nil {
 		return nil, err
 	}
+	changesURL := base.JoinPath("changes.csv").String()
 
-	indexURL := base.JoinPath("index.txt").String()
-	resp, err := afp.client.Get(indexURL)
+	resp, err := afp.client.Get(changesURL)
 	if err != nil {
 		return nil, err
 	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("fetching %s failed. Status code %d (%s)",
+			changesURL, resp.StatusCode, resp.Status)
+	}
+
 	defer resp.Body.Close()
 	var files []AdvisoryFile
-
-	scanner := bufio.NewScanner(resp.Body)
-
-	for line := 1; scanner.Scan(); line++ {
-		u := scanner.Text()
-		if _, err := url.Parse(u); err != nil {
-			lg("index.txt contains invalid URL %q in line %d", u, line)
+	c := csv.NewReader(resp.Body)
+	const (
+		pathColumn = 0
+		timeColumn = 1
+	)
+	for line := 1; ; line++ {
+		r, err := c.Read()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, err
+		}
+		if len(r) < 2 {
+			lg("%q has not enough columns in line %d", line)
+			continue
+		}
+		t, err := time.Parse(time.RFC3339, r[timeColumn])
+		if err != nil {
+			lg("%q has an invalid time stamp in line %d: %v", changesURL, line, err)
+			continue
+		}
+		// Apply date range filtering.
+		if afp.AgeAccept != nil && !afp.AgeAccept(t) {
+			continue
+		}
+		path := r[pathColumn]
+		if _, err := url.Parse(path); err != nil {
+			lg("%q contains an invalid URL %q in line %d", changesURL, path, line)
 			continue
 		}
 		files = append(files,
-			PlainAdvisoryFile(base.JoinPath(u).String()))
-	}
-
-	if err := scanner.Err(); err != nil {
-		return nil, err
+			PlainAdvisoryFile(base.JoinPath(path).String()))
 	}
 	return files, nil
 }
@@ -287,6 +314,13 @@ func (afp *AdvisoryFileProcessor) processROLIE(
 
 		rfeed.Entries(func(entry *Entry) {
 
+			// Filter if we have date checking.
+			if afp.AgeAccept != nil {
+				if pub := time.Time(entry.Published); !pub.IsZero() && !afp.AgeAccept(pub) {
+					return
+				}
+			}
+
 			var self, sha256, sha512, sign string
 
 			for i := range entry.Link {

docs/csaf_downloader.md

@@ -14,6 +14,7 @@ Application Options:
   -v, --verbose                    Verbose output
   -r, --rate=                      The average upper limit of https operations per second (defaults to unlimited)
   -w, --worker=NUM                 NUMber of concurrent downloads (default: 2)
+  -t, --timerange=RANGE            RANGE of time from which advisories to download
   -H, --header=                    One or more extra HTTP header fields
       --validator=URL              URL to validate documents remotely
       --validatorcache=FILE        FILE to cache remote validations
@@ -54,4 +55,34 @@ worker            = 2
 # validator       # not set by default
 # validatorcache  # not set by default
 validatorpreset   = ["mandatory"]
+# timerange       # not set by default
 ```
+
+The `timerange` parameter enables downloading advisories which last changes falls
+into a given intervall. There are three possible notations:
+
+1. Relative. If the given string follows the rules of being a [Go duration](https://pkg.go.dev/time@go1.20.6#ParseDuration)
+    the time interval from now minus that duration till now is used. 
+    E.g. `"3h"` means downloading the advisories that have changed in the last three hours.
+
+2. Absolute. If the given string is an RFC 3339 date timestamp the time interval between
+   this date and now is used. 
+   E.g. `"2006-01-02"` means that all files between 2006 January 2nd and now going to being
+   downloaded. 
+   Accepted patterns are:
+   - `"2006-01-02T15:04:05Z"`
+   - `"2006-01-02T15:04:05+07:00"`
+   - `"2006-01-02T15:04:05-07:00"`
+   - `"2006-01-02T15:04:05"`
+   - `"2006-01-02T15:04"`
+   - `"2006-01-02T15"`
+   - `"2006-01-02"`
+   - `"2006-01"`
+   - `"2006"`
+
+   Missing parts are set to the smallest value possible in that field.
+
+3. Range. Same as 2 but separated by a `,` to span an interval. e.g `2019,2024`
+   spans an interval from 1st January 2019 to the 1st January of 2024.
+
+All interval boundaries are inclusive.

internal/models/models.go

@@ -0,0 +1,92 @@
+// This file is Free Software under the MIT License
+// without warranty, see README.md and LICENSES/MIT.txt for details.
+//
+// SPDX-License-Identifier: MIT
+//
+// SPDX-FileCopyrightText: 2023 German Federal Office for Information Security (BSI) <https://www.bsi.bund.de>
+// Software-Engineering: 2023 Intevation GmbH <https://intevation.de>
+
+// Package models contains helper models used in the tools internally.
+package models
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+// TimeRange is a time interval.
+type TimeRange [2]time.Time
+
+// NewTimeInterval creates a new time range.
+// The time values will be sorted.
+func NewTimeInterval(a, b time.Time) TimeRange {
+	if b.Before(a) {
+		a, b = b, a
+	}
+	return TimeRange{a, b}
+}
+
+// guessDate tries to guess an RFC 3339 date time from a given string.
+func guessDate(s string) (time.Time, bool) {
+	for _, layout := range []string{
+		"2006-01-02T15:04:05Z07:00",
+		"2006-01-02T15:04:05",
+		"2006-01-02T15:04",
+		"2006-01-02T15",
+		"2006-01-02",
+		"2006-01",
+		"2006",
+	} {
+		if t, err := time.Parse(layout, s); err == nil {
+			return t, true
+		}
+	}
+	return time.Time{}, false
+}
+
+// UnmarshalText implements [encoding/text.TextUnmarshaler].
+func (tr *TimeRange) UnmarshalText(text []byte) error {
+	return tr.UnmarshalFlag(string(text))
+}
+
+// UnmarshalFlag implements [go-flags/Unmarshaler].
+func (tr *TimeRange) UnmarshalFlag(s string) error {
+	s = strings.TrimSpace(s)
+
+	// Handle relative case first.
+	if duration, err := time.ParseDuration(s); err == nil {
+		now := time.Now()
+		*tr = NewTimeInterval(now.Add(-duration), now)
+		return nil
+	}
+
+	a, b, found := strings.Cut(s, ",")
+	a, b = strings.TrimSpace(a), strings.TrimSpace(b)
+
+	// Only start date?
+	if !found {
+		start, ok := guessDate(a)
+		if !ok {
+			return fmt.Errorf("%q is not a valid RFC date time", a)
+		}
+		*tr = NewTimeInterval(start, time.Now())
+		return nil
+	}
+	// Real interval
+	start, ok := guessDate(a)
+	if !ok {
+		return fmt.Errorf("%q is not a valid RFC date time", a)
+	}
+	end, ok := guessDate(b)
+	if !ok {
+		return fmt.Errorf("%q is not a valid RFC date time", b)
+	}
+	*tr = NewTimeInterval(start, end)
+	return nil
+}
+
+// Contains return true if the given time is inside this time interval.
+func (tr TimeRange) Contains(t time.Time) bool {
+	return !(t.Before(tr[0]) || t.After(tr[1]))
+}