[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, 46 insertions, 0 deletions

diff --git a/vendor/github.com/dustin/go-humanize/ftoa.go b/vendor/github.com/dustin/go-humanize/ftoa.go
new file mode 100644
index 000000000..1c62b640d
--- /dev/null
+++ b/vendor/github.com/dustin/go-humanize/ftoa.go
@@ -0,0 +1,46 @@
+package humanize
+
+import (
+	"strconv"
+	"strings"
+)
+
+func stripTrailingZeros(s string) string {
+	offset := len(s) - 1
+	for offset > 0 {
+		if s[offset] == '.' {
+			offset--
+			break
+		}
+		if s[offset] != '0' {
+			break
+		}
+		offset--
+	}
+	return s[:offset+1]
+}
+
+func stripTrailingDigits(s string, digits int) string {
+	if i := strings.Index(s, "."); i >= 0 {
+		if digits <= 0 {
+			return s[:i]
+		}
+		i++
+		if i+digits >= len(s) {
+			return s
+		}
+		return s[:i+digits]
+	}
+	return s
+}
+
+// Ftoa converts a float to a string with no trailing zeros.
+func Ftoa(num float64) string {
+	return stripTrailingZeros(strconv.FormatFloat(num, 'f', 6, 64))
+}
+
+// FtoaWithDigits converts a float to a string but limits the resulting string
+// to the given number of decimal places, and no trailing zeros.
+func FtoaWithDigits(num float64, digits int) string {
+	return stripTrailingZeros(stripTrailingDigits(strconv.FormatFloat(num, 'f', 6, 64), digits))
+}