mediaapi: Add thumbnail support (#132)

* vendor: Add bimg image processing library

bimg is MIT licensed. It depends on the C library libvips which is LGPL
v2.1+ licensed. libvips must be installed separately.

* mediaapi: Add YAML config file support

* mediaapi: Add thumbnail support

* mediaapi: Add missing thumbnail files

* travis: Add ppa and install libvips-dev

* travis: Another ppa and install libvips-dev attempt

* travis: Add sudo: required for sudo apt* usage

* mediaapi/thumbnailer: Make comparison code more readable

* mediaapi: Simplify logging of thumbnail properties

* mediaapi/thumbnailer: Rename metrics to fitness

Metrics is used in the context of monitoring with Prometheus so renaming
to avoid confusion.

* mediaapi/thumbnailer: Use math.Inf() for max aspect and size

* mediaapi/thumbnailer: Limit number of parallel generators

Fall back to selecting from already-/pre-generated thumbnails or serving
the original.

* mediaapi/thumbnailer: Split bimg code into separate file

* vendor: Add github.com/nfnt/resize pure go image scaler

* mediaapi/thumbnailer: Add nfnt/resize thumbnailer

* travis: Don't install libvips-dev via ppa

* mediaapi: Add notes to README about resizers

* mediaapi: Elaborate on scaling libs in README

vendor/src/github.com/tj/go-debug/debug_test.go

@@ -0,0 +1,152 @@
+package debug
+
+import "testing"
+import "strings"
+import "bytes"
+import "time"
+
+func assertContains(t *testing.T, str, substr string) {
+	if !strings.Contains(str, substr) {
+		t.Fatalf("expected %q to contain %q", str, substr)
+	}
+}
+
+func assertNotContains(t *testing.T, str, substr string) {
+	if strings.Contains(str, substr) {
+		t.Fatalf("expected %q to not contain %q", str, substr)
+	}
+}
+
+func TestDefault(t *testing.T) {
+	var b []byte
+	buf := bytes.NewBuffer(b)
+	SetWriter(buf)
+
+	debug := Debug("foo")
+	debug("something")
+	debug("here")
+	debug("whoop")
+
+	if buf.Len() != 0 {
+		t.Fatalf("buffer should be empty")
+	}
+}
+
+func TestEnable(t *testing.T) {
+	var b []byte
+	buf := bytes.NewBuffer(b)
+	SetWriter(buf)
+
+	Enable("foo")
+
+	debug := Debug("foo")
+	debug("something")
+	debug("here")
+	debug("whoop")
+
+	if buf.Len() == 0 {
+		t.Fatalf("buffer should have output")
+	}
+
+	str := string(buf.Bytes())
+	assertContains(t, str, "something")
+	assertContains(t, str, "here")
+	assertContains(t, str, "whoop")
+}
+
+func TestMultipleOneEnabled(t *testing.T) {
+	var b []byte
+	buf := bytes.NewBuffer(b)
+	SetWriter(buf)
+
+	Enable("foo")
+
+	foo := Debug("foo")
+	foo("foo")
+
+	bar := Debug("bar")
+	bar("bar")
+
+	if buf.Len() == 0 {
+		t.Fatalf("buffer should have output")
+	}
+
+	str := string(buf.Bytes())
+	assertContains(t, str, "foo")
+	assertNotContains(t, str, "bar")
+}
+
+func TestMultipleEnabled(t *testing.T) {
+	var b []byte
+	buf := bytes.NewBuffer(b)
+	SetWriter(buf)
+
+	Enable("foo,bar")
+
+	foo := Debug("foo")
+	foo("foo")
+
+	bar := Debug("bar")
+	bar("bar")
+
+	if buf.Len() == 0 {
+		t.Fatalf("buffer should have output")
+	}
+
+	str := string(buf.Bytes())
+	assertContains(t, str, "foo")
+	assertContains(t, str, "bar")
+}
+
+func TestEnableDisable(t *testing.T) {
+	var b []byte
+	buf := bytes.NewBuffer(b)
+	SetWriter(buf)
+
+	Enable("foo,bar")
+	Disable()
+
+	foo := Debug("foo")
+	foo("foo")
+
+	bar := Debug("bar")
+	bar("bar")
+
+	if buf.Len() != 0 {
+		t.Fatalf("buffer should not have output")
+	}
+}
+
+func ExampleEnable() {
+	Enable("mongo:connection")
+	Enable("mongo:*")
+	Enable("foo,bar,baz")
+	Enable("*")
+}
+
+func ExampleDebug() {
+	var debug = Debug("single")
+
+	for {
+		debug("sending mail")
+		debug("send email to %s", "tobi@segment.io")
+		debug("send email to %s", "loki@segment.io")
+		debug("send email to %s", "jane@segment.io")
+		time.Sleep(500 * time.Millisecond)
+	}
+}
+
+func BenchmarkDisabled(b *testing.B) {
+	debug := Debug("something")
+	for i := 0; i < b.N; i++ {
+		debug("stuff")
+	}
+}
+
+func BenchmarkNonMatch(b *testing.B) {
+	debug := Debug("something")
+	Enable("nonmatch")
+	for i := 0; i < b.N; i++ {
+		debug("stuff")
+	}
+}