logparser input plugin

closes #102
closes #328

filter/filter.go

@@ -0,0 +1,79 @@
+package filter
+
+import (
+	"strings"
+
+	"github.com/gobwas/glob"
+)
+
+type Filter interface {
+	Match(string) bool
+}
+
+// CompileFilter takes a list of string filters and returns a Filter interface
+// for matching a given string against the filter list. The filter list
+// supports glob matching too, ie:
+//
+//   f, _ := CompileFilter([]string{"cpu", "mem", "net*"})
+//   f.Match("cpu")     // true
+//   f.Match("network") // true
+//   f.Match("memory")  // false
+//
+func CompileFilter(filters []string) (Filter, error) {
+	// return if there is nothing to compile
+	if len(filters) == 0 {
+		return nil, nil
+	}
+
+	// check if we can compile a non-glob filter
+	noGlob := true
+	for _, filter := range filters {
+		if hasMeta(filter) {
+			noGlob = false
+			break
+		}
+	}
+
+	switch {
+	case noGlob:
+		// return non-globbing filter if not needed.
+		return compileFilterNoGlob(filters), nil
+	case len(filters) == 1:
+		return glob.Compile(filters[0])
+	default:
+		return glob.Compile("{" + strings.Join(filters, ",") + "}")
+	}
+}
+
+// hasMeta reports whether path contains any magic glob characters.
+func hasMeta(s string) bool {
+	return strings.IndexAny(s, "*?[") >= 0
+}
+
+type filter struct {
+	m map[string]struct{}
+}
+
+func (f *filter) Match(s string) bool {
+	_, ok := f.m[s]
+	return ok
+}
+
+type filtersingle struct {
+	s string
+}
+
+func (f *filtersingle) Match(s string) bool {
+	return f.s == s
+}
+
+func compileFilterNoGlob(filters []string) Filter {
+	if len(filters) == 1 {
+		return &filtersingle{s: filters[0]}
+	}
+	out := filter{m: make(map[string]struct{})}
+	for _, filter := range filters {
+		out.m[filter] = struct{}{}
+	}
+	return &out
+}

filter/filter_test.go

@@ -0,0 +1,96 @@
+package filter
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCompileFilter(t *testing.T) {
+	f, err := CompileFilter([]string{})
+	assert.NoError(t, err)
+	assert.Nil(t, f)
+
+	f, err = CompileFilter([]string{"cpu"})
+	assert.NoError(t, err)
+	assert.True(t, f.Match("cpu"))
+	assert.False(t, f.Match("cpu0"))
+	assert.False(t, f.Match("mem"))
+
+	f, err = CompileFilter([]string{"cpu*"})
+	assert.NoError(t, err)
+	assert.True(t, f.Match("cpu"))
+	assert.True(t, f.Match("cpu0"))
+	assert.False(t, f.Match("mem"))
+
+	f, err = CompileFilter([]string{"cpu", "mem"})
+	assert.NoError(t, err)
+	assert.True(t, f.Match("cpu"))
+	assert.False(t, f.Match("cpu0"))
+	assert.True(t, f.Match("mem"))
+
+	f, err = CompileFilter([]string{"cpu", "mem", "net*"})
+	assert.NoError(t, err)
+	assert.True(t, f.Match("cpu"))
+	assert.False(t, f.Match("cpu0"))
+	assert.True(t, f.Match("mem"))
+	assert.True(t, f.Match("network"))
+}
+
+var benchbool bool
+
+func BenchmarkFilterSingleNoGlobFalse(b *testing.B) {
+	f, _ := CompileFilter([]string{"cpu"})
+	var tmp bool
+	for n := 0; n < b.N; n++ {
+		tmp = f.Match("network")
+	}
+	benchbool = tmp
+}
+
+func BenchmarkFilterSingleNoGlobTrue(b *testing.B) {
+	f, _ := CompileFilter([]string{"cpu"})
+	var tmp bool
+	for n := 0; n < b.N; n++ {
+		tmp = f.Match("cpu")
+	}
+	benchbool = tmp
+}
+
+func BenchmarkFilter(b *testing.B) {
+	f, _ := CompileFilter([]string{"cpu", "mem", "net*"})
+	var tmp bool
+	for n := 0; n < b.N; n++ {
+		tmp = f.Match("network")
+	}
+	benchbool = tmp
+}
+
+func BenchmarkFilterNoGlob(b *testing.B) {
+	f, _ := CompileFilter([]string{"cpu", "mem", "net"})
+	var tmp bool
+	for n := 0; n < b.N; n++ {
+		tmp = f.Match("net")
+	}
+	benchbool = tmp
+}
+
+func BenchmarkFilter2(b *testing.B) {
+	f, _ := CompileFilter([]string{"aa", "bb", "c", "ad", "ar", "at", "aq",
+		"aw", "az", "axxx", "ab", "cpu", "mem", "net*"})
+	var tmp bool
+	for n := 0; n < b.N; n++ {
+		tmp = f.Match("network")
+	}
+	benchbool = tmp
+}
+
+func BenchmarkFilter2NoGlob(b *testing.B) {
+	f, _ := CompileFilter([]string{"aa", "bb", "c", "ad", "ar", "at", "aq",
+		"aw", "az", "axxx", "ab", "cpu", "mem", "net"})
+	var tmp bool
+	for n := 0; n < b.N; n++ {
+		tmp = f.Match("net")
+	}
+	benchbool = tmp
+}