add rotatingloghandler which removes older log entries

4 files changed, 44 insertions, 8 deletions

diff --git a/frontend/frontend.go b/frontend/frontend.go
index abb5a3db4f70..f0ea46e497c9 100644
--- a/frontend/frontend.go
+++ b/frontend/frontend.go
@@ -11,10 +11,9 @@ import (
 	"github.com/rakyll/statik/fs"
 
 	"github.com/tweag/gerrit-queue/gerrit"
+	"github.com/tweag/gerrit-queue/misc"
 	_ "github.com/tweag/gerrit-queue/statik" // register static assets
 	"github.com/tweag/gerrit-queue/submitqueue"
-
-	"github.com/apex/log/handlers/memory"
 )
 
 //loadTemplate loads a list of templates, relative to the statikFS root, and a FuncMap, and returns a template object
@@ -48,7 +47,7 @@ func loadTemplate(templateNames []string, funcMap template.FuncMap) (*template.T
 }
 
 // MakeFrontend returns a http.Handler
-func MakeFrontend(memoryHandler *memory.Handler, gerritClient *gerrit.Client, runner *submitqueue.Runner) http.Handler {
+func MakeFrontend(rotatingLogHandler *misc.RotatingLogHandler, gerritClient *gerrit.Client, runner *submitqueue.Runner) http.Handler {
 	router := gin.Default()
 
 	projectName := gerritClient.GetProjectName()
@@ -88,7 +87,7 @@ func MakeFrontend(memoryHandler *memory.Handler, gerritClient *gerrit.Client, ru
 			"HEAD":             HEAD,
 
 			// History
-			"memory": memoryHandler,
+			"memory": rotatingLogHandler,
 		})
 	})
 	return router
diff --git a/go.sum b/go.sum
index 12ab50bbd053..78d9662c9383 100644
--- a/go.sum
+++ b/go.sum
@@ -9,6 +9,7 @@ github.com/aws/aws-sdk-go v1.20.6/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN
 github.com/aybabtme/rgbterm v0.0.0-20170906152045-cc83f3b3ce59/go.mod h1:q/89r3U2H7sSsE2t6Kca0lfwTK8JdoNGS/yzM/4iH5I=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d h1:U+s90UTSYgptZMwQh2aRr3LuazLJIa+Pg3Kc1ylSYVY=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
@@ -41,6 +42,7 @@ github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+W
 github.com/onsi/gomega v1.5.0/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rakyll/statik v0.1.6 h1:uICcfUXpgqtw2VopbIncslhAmE5hwc4g20TEyEENBNs=
 github.com/rakyll/statik v0.1.6/go.mod h1:OEi9wJV/fMUAGx1eNjq75DKDsJVuEv1U0oYdX6GX8Zs=
@@ -54,6 +56,7 @@ github.com/smartystreets/assertions v1.0.0/go.mod h1:kHHU4qYBaI3q23Pp3VPrmWhuIUr
 github.com/smartystreets/go-aws-auth v0.0.0-20180515143844-0c1422d1fdb9/go.mod h1:SnhjPscd9TpLiy1LpzGSKh3bXCfxxXuqd9xmQJy3slM=
 github.com/smartystreets/gunit v1.0.0/go.mod h1:qwPWnhz6pn0NnRBP++URONOVyNkPyr4SauJk4cUOwJs=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/tj/assert v0.0.0-20171129193455-018094318fb0/go.mod h1:mZ9/Rh9oLWpLLDRpvE+3b7gP/C2YyLFYxNmcLnPTMe0=
 github.com/tj/go-elastic v0.0.0-20171221160941-36157cbbebc2/go.mod h1:WjeM0Oo1eNAjXGDx2yma7uG2XoyRZTq1uv3M/o7imD0=
diff --git a/main.go b/main.go
index 1be379904b29..338be7865b9e 100644
--- a/main.go
+++ b/main.go
@@ -10,12 +10,12 @@ import (
 
 	"github.com/tweag/gerrit-queue/frontend"
 	"github.com/tweag/gerrit-queue/gerrit"
+	"github.com/tweag/gerrit-queue/misc"
 	"github.com/tweag/gerrit-queue/submitqueue"
 
 	"github.com/urfave/cli"
 
 	"github.com/apex/log"
-	"github.com/apex/log/handlers/memory"
 	"github.com/apex/log/handlers/multi"
 	"github.com/apex/log/handlers/text"
 )
@@ -78,11 +78,11 @@ func main() {
 		},
 	}
 
-	memoryLogHandler := memory.New()
+	rotatingLogHandler := misc.NewRotatingLogHandler(10000)
 	l := &log.Logger{
 		Handler: multi.New(
 			text.New(os.Stderr),
-			memoryLogHandler,
+			rotatingLogHandler,
 		),
 		Level: log.DebugLevel,
 	}
@@ -96,7 +96,7 @@ func main() {
 
 		runner := submitqueue.NewRunner(l, gerrit, submitQueueTag)
 
-		handler := frontend.MakeFrontend(memoryLogHandler, gerrit, runner)
+		handler := frontend.MakeFrontend(rotatingLogHandler, gerrit, runner)
 
 		// fetch only on first run
 		runner.Trigger(fetchOnly)
diff --git a/misc/rotatingloghandler.go b/misc/rotatingloghandler.go
new file mode 100644
index 000000000000..3d4c5f3a837a
--- /dev/null
+++ b/misc/rotatingloghandler.go
@@ -0,0 +1,34 @@
+package misc
+
+import (
+	"sync"
+
+	"github.com/apex/log"
+)
+
+// RotatingLogHandler implementation.
+type RotatingLogHandler struct {
+	mu         sync.Mutex
+	Entries    []*log.Entry
+	maxEntries int
+}
+
+// NewRotatingLogHandler creates a new rotating log handler
+func NewRotatingLogHandler(maxEntries int) *RotatingLogHandler {
+	return &RotatingLogHandler{
+		maxEntries: maxEntries,
+	}
+}
+
+// HandleLog implements log.Handler.
+func (h *RotatingLogHandler) HandleLog(e *log.Entry) error {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	// drop tail if we have more entries than maxEntries
+	if len(h.Entries) > h.maxEntries {
+		h.Entries = append([]*log.Entry{e}, h.Entries[:(h.maxEntries-2)]...)
+	} else {
+		h.Entries = append([]*log.Entry{e}, h.Entries...)
+	}
+	return nil
+}