[feature] S3 support (#674)

* feat: vendor minio client

* feat: introduce storage package with s3 support

* feat: serve s3 files directly

this saves a lot of bandwith as the files are fetched from the object
store directly

* fix: use explicit local storage in tests

* feat: integrate s3 storage with the main server

* fix: add s3 config to cli tests

* docs: explicitly set values in example config

also adds license header to the storage package

* fix: use better http status code on s3 redirect

HTTP 302 Found is the best fit, as it signifies that the resource
requested was found but not under its presumed URL

307/TemporaryRedirect would mean that this resource is usually located
here, not in this case

303/SeeOther indicates that the redirection does not link to the
requested resource but to another page

* refactor: use context in storage driver interface

1 files changed, 117 insertions, 0 deletions

diff --git a/vendor/github.com/dustin/go-humanize/times.go b/vendor/github.com/dustin/go-humanize/times.go
new file mode 100644
index 000000000..dd3fbf5ef
--- /dev/null
+++ b/vendor/github.com/dustin/go-humanize/times.go
@@ -0,0 +1,117 @@
+package humanize
+
+import (
+	"fmt"
+	"math"
+	"sort"
+	"time"
+)
+
+// Seconds-based time units
+const (
+	Day      = 24 * time.Hour
+	Week     = 7 * Day
+	Month    = 30 * Day
+	Year     = 12 * Month
+	LongTime = 37 * Year
+)
+
+// Time formats a time into a relative string.
+//
+// Time(someT) -> "3 weeks ago"
+func Time(then time.Time) string {
+	return RelTime(then, time.Now(), "ago", "from now")
+}
+
+// A RelTimeMagnitude struct contains a relative time point at which
+// the relative format of time will switch to a new format string.  A
+// slice of these in ascending order by their "D" field is passed to
+// CustomRelTime to format durations.
+//
+// The Format field is a string that may contain a "%s" which will be
+// replaced with the appropriate signed label (e.g. "ago" or "from
+// now") and a "%d" that will be replaced by the quantity.
+//
+// The DivBy field is the amount of time the time difference must be
+// divided by in order to display correctly.
+//
+// e.g. if D is 2*time.Minute and you want to display "%d minutes %s"
+// DivBy should be time.Minute so whatever the duration is will be
+// expressed in minutes.
+type RelTimeMagnitude struct {
+	D      time.Duration
+	Format string
+	DivBy  time.Duration
+}
+
+var defaultMagnitudes = []RelTimeMagnitude{
+	{time.Second, "now", time.Second},
+	{2 * time.Second, "1 second %s", 1},
+	{time.Minute, "%d seconds %s", time.Second},
+	{2 * time.Minute, "1 minute %s", 1},
+	{time.Hour, "%d minutes %s", time.Minute},
+	{2 * time.Hour, "1 hour %s", 1},
+	{Day, "%d hours %s", time.Hour},
+	{2 * Day, "1 day %s", 1},
+	{Week, "%d days %s", Day},
+	{2 * Week, "1 week %s", 1},
+	{Month, "%d weeks %s", Week},
+	{2 * Month, "1 month %s", 1},
+	{Year, "%d months %s", Month},
+	{18 * Month, "1 year %s", 1},
+	{2 * Year, "2 years %s", 1},
+	{LongTime, "%d years %s", Year},
+	{math.MaxInt64, "a long while %s", 1},
+}
+
+// RelTime formats a time into a relative string.
+//
+// It takes two times and two labels.  In addition to the generic time
+// delta string (e.g. 5 minutes), the labels are used applied so that
+// the label corresponding to the smaller time is applied.
+//
+// RelTime(timeInPast, timeInFuture, "earlier", "later") -> "3 weeks earlier"
+func RelTime(a, b time.Time, albl, blbl string) string {
+	return CustomRelTime(a, b, albl, blbl, defaultMagnitudes)
+}
+
+// CustomRelTime formats a time into a relative string.
+//
+// It takes two times two labels and a table of relative time formats.
+// In addition to the generic time delta string (e.g. 5 minutes), the
+// labels are used applied so that the label corresponding to the
+// smaller time is applied.
+func CustomRelTime(a, b time.Time, albl, blbl string, magnitudes []RelTimeMagnitude) string {
+	lbl := albl
+	diff := b.Sub(a)
+
+	if a.After(b) {
+		lbl = blbl
+		diff = a.Sub(b)
+	}
+
+	n := sort.Search(len(magnitudes), func(i int) bool {
+		return magnitudes[i].D > diff
+	})
+
+	if n >= len(magnitudes) {
+		n = len(magnitudes) - 1
+	}
+	mag := magnitudes[n]
+	args := []interface{}{}
+	escaped := false
+	for _, ch := range mag.Format {
+		if escaped {
+			switch ch {
+			case 's':
+				args = append(args, lbl)
+			case 'd':
+				args = append(args, diff/mag.DivBy)
+			}
+			escaped = false
+		} else {
+			escaped = ch == '%'
+		}
+	}
+	return fmt.Sprintf(mag.Format, args...)
+}