Add docker scratch for agent and collector (#156)

* Add docker from scratch linux for agent and collector

* Fix flaky test that depended on timing

.gitignore

@@ -3,3 +3,8 @@ bin/
 # Miscellaneous files
 *.sw[op]
 *.DS_Store
+
+# Binaries are copied (as needed) to the same location as their respective Dockerfile in
+# order to simplify docker build commands. Ignore these files if proper clean up fails.
+cmd/ocagent/ocagent_linux
+cmd/occollector/occollector_linux

Makefile

@@ -1,6 +1,6 @@
 ALL_SRC := $(shell find . -type f -name '*.go' -not -path "./vendor/*")
 
-GOTEST_OPT=-v -race
+GOTEST_OPT?=-v -race
 GOTEST=go test
 GOFMT=gofmt
 GOOS=$(shell go env GOOS)
@@ -14,10 +14,6 @@ BUILD_INFO=-ldflags "-X $(BUILD_INFO_IMPORT_PATH).GitHash=$(GIT_SHA)"
 .PHONY: default_goal
 default_goal: fmt test
 
-.PHONY: clean
-clean:
-	rm -rf bin/ 
-
 .PHONY: test
 test:
 	$(GOTEST) $(GOTEST_OPT) ./...
@@ -39,6 +35,28 @@ agent:
 collector:
 	CGO_ENABLED=0 go build -o ./bin/occollector_$(GOOS) $(BUILD_INFO) ./cmd/occollector
 
+.PHONY: docker-component # Not intended to be used directly
+docker-component: check-component
+	GOOS=linux $(MAKE) $(COMPONENT)
+	cp ./bin/oc$(COMPONENT)_linux ./cmd/oc$(COMPONENT)/
+	docker build -t oc$(COMPONENT) ./cmd/oc$(COMPONENT)/
+	rm ./cmd/oc$(COMPONENT)/oc$(COMPONENT)_linux
+
+.PHONY: check-component
+check-component:
+ifndef COMPONENT
+	$(error COMPONENT variable was not defined)
+endif
+
+.PHONY: docker-agent
+docker-agent:
+	COMPONENT=agent $(MAKE) docker-component
+
+.PHONY: docker-collector
+docker-collector: 
+	COMPONENT=collector $(MAKE) docker-component
+
+
 .PHONY: binaries
 binaries: agent collector
 

cmd/ocagent/Dockerfile

@@ -0,0 +1,9 @@
+# Use a helper to create an emtpy configuration since the agent requires such file
+FROM alpine:3.7 as helper
+RUN touch ./config.yaml
+
+FROM scratch
+COPY ocagent_linux /
+COPY --from=helper ./config.yaml config.yaml
+ENTRYPOINT ["/ocagent_linux"]
+EXPOSE 55678 55679

cmd/ocagent/config.go

@@ -47,7 +47,7 @@ import (
 //      port: 55679
 
 const (
-	defaultOCInterceptorAddress = "localhost:55678"
+	defaultOCInterceptorAddress = ":55678"
 	defaultZPagesPort           = 55679
 )
 

cmd/ocagent/main.go

@@ -121,14 +121,15 @@ func runZPages(port int) func() error {
 		log.Fatalf("Failed to bind to run zPages on %q: %v", addr, err)
 	}
 
+	srv := http.Server{Handler: zPagesMux}
 	go func() {
 		log.Printf("Running zPages at %q", addr)
-		if err := http.Serve(ln, zPagesMux); err != nil {
+		if err := srv.Serve(ln); err != nil && err != http.ErrServerClosed {
 			log.Fatalf("Failed to serve zPages: %v", err)
 		}
 	}()
 
-	return ln.Close
+	return srv.Close
 }
 
 func runOCInterceptor(addr string, sr spanreceiver.SpanReceiver) (doneFn func() error, err error) {
@@ -152,13 +153,14 @@ func runOCInterceptor(addr string, sr spanreceiver.SpanReceiver) (doneFn func()
 	agenttracepb.RegisterTraceServiceServer(srv, oci)
 	go func() {
 		log.Printf("Running OpenCensus interceptor as a gRPC service at %q", addr)
-
-		// Not using log.Fatalf(srv.Serve(ln)) because CTRL-C will close the listener as the user requested
-		// and that log.Fatalf will produce an unrelated but misleading error:
-		//     "Failed to run OpenCensus interceptor: accept tcp 127.0.0.1:55678: use of closed network connection"
-		_ = srv.Serve(ln)
+		if err := srv.Serve(ln); err != nil {
+			log.Fatalf("Failed to run OpenCensus interceptor: %v", err)
+		}
 	}()
-	doneFn = ln.Close
+	doneFn = func() error {
+		srv.Stop()
+		return nil
+	}
 	return doneFn, nil
 }
 

cmd/occollector/Dockerfile

@@ -0,0 +1,4 @@
+FROM scratch
+COPY occollector_linux /
+ENTRYPOINT ["/occollector_linux"]
+EXPOSE 55678

cmd/occollector/main.go

@@ -42,7 +42,7 @@ import (
 )
 
 const (
-	defaultOCAddress = "localhost:55678"
+	defaultOCAddress = ":55678"
 )
 
 func main() {
@@ -103,7 +103,12 @@ func runOCServerWithInterceptor(addr string, logger *zap.Logger) (func() error,
 		}
 	}()
 
-	return lis.Close, nil
+	closeFn := func() error {
+		grpcSrv.Stop()
+		return nil
+	}
+
+	return closeFn, nil
 }
 
 type fakeSpanReceiver struct {

exporter/exporterparser/zipkin_test.go

@@ -21,9 +21,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"strings"
-	"sync"
 	"testing"
-	"time"
 
 	"github.com/census-instrumentation/opencensus-service/exporter"
 	"github.com/census-instrumentation/opencensus-service/exporter/exporterparser"
@@ -41,10 +39,12 @@ import (
 //
 // The rest of the fields should match up exactly
 func TestZipkinExportersFromYAML_roundtripJSON(t *testing.T) {
-	cb := newConcurrentBuffer()
+	responseReady := make(chan bool)
+	buf := new(bytes.Buffer)
 	cst := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		io.Copy(cb, r.Body)
+		io.Copy(buf, r.Body)
 		r.Body.Close()
+		responseReady <- true
 	}))
 	defer cst.Close()
 
@@ -79,9 +79,8 @@ exporters:
 	req, _ := http.NewRequest("POST", "https://tld.org/", strings.NewReader(zipkinSpansJSONJavaLibrary))
 	responseWriter := httptest.NewRecorder()
 	zi.ServeHTTP(responseWriter, req)
-	// Just for 100X longer than the Zipkin reporting period
-	// because -race slows things down a lot.
-	<-time.After(100 * time.Millisecond)
+	// Wait for the server to write the response.
+	<-responseReady
 
 	// We expect back the exact JSON that was intercepted
 	want := testutils.GenerateNormalizedJSON(`
@@ -111,38 +110,13 @@ exporters:
 }]`)
 
 	// Finally we need to inspect the output
-	gotBytes, _ := ioutil.ReadAll(cb)
+	gotBytes, _ := ioutil.ReadAll(buf)
 	got := testutils.GenerateNormalizedJSON(string(gotBytes))
 	if got != want {
 		t.Errorf("RoundTrip result do not match:\nGot\n %s\n\nWant\n: %s\n", got, want)
 	}
 }
 
-type concurrentBuffer struct {
-	mu  sync.Mutex
-	buf *bytes.Buffer
-}
-
-func newConcurrentBuffer() *concurrentBuffer {
-	return &concurrentBuffer{
-		buf: new(bytes.Buffer),
-	}
-}
-
-func (cb *concurrentBuffer) Write(b []byte) (int, error) {
-	cb.mu.Lock()
-	defer cb.mu.Unlock()
-
-	return cb.buf.Write(b)
-}
-
-func (cb *concurrentBuffer) Read(b []byte) (int, error) {
-	cb.mu.Lock()
-	defer cb.mu.Unlock()
-
-	return cb.buf.Read(b)
-}
-
 const zipkinSpansJSONJavaLibrary = `
 [{
   "traceId": "4d1e00c0db9010db86154a4ba6e91385",