Makefile: build promtail with CGO_ENABLED if GOHOSTOS=GOOS=linux

Makefile

@@ -38,11 +38,14 @@ APP_GO_FILES := $(shell find . $(DONT_FIND) -name .y.go -prune -o -name .pb.go -
 
 # Build flags
 VPREFIX := github.com/grafana/loki/vendor/github.com/prometheus/common/version
-GO_FLAGS := -ldflags "-extldflags \"-static\" -s -w -X $(VPREFIX).Branch=$(GIT_BRANCH) -X $(VPREFIX).Version=$(IMAGE_TAG) -X $(VPREFIX).Revision=$(GIT_REVISION)" -tags netgo
+GO_LDFLAGS   := -s -w -X $(VPREFIX).Branch=$(GIT_BRANCH) -X $(VPREFIX).Version=$(IMAGE_TAG) -X $(VPREFIX).Revision=$(GIT_REVISION)
+GO_FLAGS     := -ldflags "-extldflags \"-static\" $(GO_LDFLAGS)" -tags netgo
+DYN_GO_FLAGS := -ldflags "$(GO_LDFLAGS)" -tags netgo
 # Per some websites I've seen to add `-gcflags "all=-N -l"`, the gcflags seem poorly if at all documented
 # the best I could dig up is -N disables optimizations and -l disables inlining which should make debugging match source better.
 # Also remove the -s and -w flags present in the normal build which strip the symbol table and the DWARF symbol table.
-DEBUG_GO_FLAGS := -gcflags "all=-N -l" -ldflags "-extldflags \"-static\" -X $(VPREFIX).Branch=$(GIT_BRANCH) -X $(VPREFIX).Version=$(IMAGE_TAG) -X $(VPREFIX).Revision=$(GIT_REVISION)" -tags netgo
+DEBUG_GO_FLAGS     := -gcflags "all=-N -l" -ldflags "-extldflags \"-static\" $(GO_LDFLAGS)" -tags netgo
+DYN_DEBUG_GO_FLAGS := -gcflags "all=-N -l" -ldflags "$(GO_LDFLAGS)" -tags netgo
 
 NETGO_CHECK = @strings $@ | grep cgo_stub\\\.go >/dev/null || { \
        rm $@; \
@@ -149,6 +152,19 @@ cmd/loki-canary/loki-canary: $(APP_GO_FILES) cmd/loki-canary/main.go
 # Promtail #
 ############
 
+PROMTAIL_CGO := 0
+PROMTAIL_GO_FLAGS := $(GO_FLAGS)
+PROMTAIL_DEBUG_GO_FLAGS := $(DEBUG_GO_FLAGS)
+
+# Validate GOHOSTOS=linux && GOOS=linux to use CGO.
+ifeq ($(shell go env GOHOSTOS),linux)
+ifeq ($(shell go env GOOS),linux)
+PROMTAIL_CGO = 1
+PROMTAIL_GO_FLAGS = $(DYN_GO_FLAGS)
+PROMTAIL_DEBUG_GO_FLAGS = $(DYN_DEBUG_GO_FLAGS)
+endif
+endif
+
 promtail: yacc cmd/promtail/promtail
 promtail-debug: yacc cmd/promtail/promtail-debug
 
@@ -161,11 +177,11 @@ $(PROMTAIL_GENERATED_FILE): $(PROMTAIL_UI_FILES)
 	GOOS=$(shell go env GOHOSTOS) go generate -x -v ./pkg/promtail/server/ui
 
 cmd/promtail/promtail: $(APP_GO_FILES) $(PROMTAIL_GENERATED_FILE) cmd/promtail/main.go
-	CGO_ENABLED=0 go build $(GO_FLAGS) -o $@ ./$(@D)
+	CGO_ENABLED=$(PROMTAIL_CGO) go build $(PROMTAIL_GO_FLAGS) -o $@ ./$(@D)
 	$(NETGO_CHECK)
 
 cmd/promtail/promtail-debug: $(APP_GO_FILES) pkg/promtail/server/ui/assets_vfsdata.go cmd/promtail/main.go
-	CGO_ENABLED=0 go build $(DEBUG_GO_FLAGS) -o $@ ./$(@D)
+	CGO_ENABLED=$(PROMTAIL_CGO) go build $(PROMTAIL_DEBUG_GO_FLAGS) -o $@ ./$(@D)
 	$(NETGO_CHECK)
 
 ########
@@ -231,14 +247,14 @@ ifeq ($(BUILD_IN_CONTAINER),true)
 		-v $(shell pwd):/go/src/github.com/grafana/loki \
 		$(IMAGE_PREFIX)/loki-build-image:$(BUILD_IMAGE_VERSION) $@;
 else
-	case "$@" in 	\
-  	vendor*)			\
-  		protoc -I ./vendor:./$(@D) --gogoslick_out=plugins=grpc:./vendor ./$(patsubst %.pb.go,%.proto,$@); \
-  		;;					\
-  	*)						\
-  		protoc -I ./vendor:./$(@D) --gogoslick_out=Mgoogle/protobuf/timestamp.proto=github.com/gogo/protobuf/types,plugins=grpc:./$(@D) ./$(patsubst %.pb.go,%.proto,$@); \
-  		;;					\
-  	esac
+	case "$@" in	\
+		vendor*)			\
+			protoc -I ./vendor:./$(@D) --gogoslick_out=plugins=grpc:./vendor ./$(patsubst %.pb.go,%.proto,$@); \
+			;;					\
+		*)						\
+			protoc -I ./vendor:./$(@D) --gogoslick_out=Mgoogle/protobuf/timestamp.proto=github.com/gogo/protobuf/types,plugins=grpc:./$(@D) ./$(patsubst %.pb.go,%.proto,$@); \
+			;;					\
+		esac
 endif
 
 

cmd/docker-driver/Dockerfile

@@ -1,4 +1,4 @@
-ARG BUILD_IMAGE=grafana/loki-build-image:0.2.1
+ARG BUILD_IMAGE=grafana/loki-build-image:latest
 # Directories in this file are referenced from the root of the project not this folder
 # This file is intented to be called from the root like so:
 # docker build -t grafana/loki -f cmd/loki/Dockerfile .

cmd/loki-canary/Dockerfile

@@ -1,4 +1,4 @@
-ARG BUILD_IMAGE=grafana/loki-build-image:0.2.1
+ARG BUILD_IMAGE=grafana/loki-build-image:latest
 # Directories in this file are referenced from the root of the project not this folder
 # This file is intented to be called from the root like so:
 # docker build -t grafana/promtail -f cmd/promtail/Dockerfile .

cmd/loki/Dockerfile

@@ -1,4 +1,4 @@
-ARG BUILD_IMAGE=grafana/loki-build-image:0.2.1
+ARG BUILD_IMAGE=grafana/loki-build-image:latest
 # Directories in this file are referenced from the root of the project not this folder
 # This file is intented to be called from the root like so:
 # docker build -t grafana/loki -f cmd/loki/Dockerfile .

cmd/promtail/Dockerfile

@@ -1,4 +1,4 @@
-ARG BUILD_IMAGE=grafana/loki-build-image:0.2.1
+ARG BUILD_IMAGE=grafana/loki-build-image:latest
 # Directories in this file are referenced from the root of the project not this folder
 # This file is intented to be called from the root like so:
 # docker build -t grafana/promtail -f cmd/promtail/Dockerfile .
@@ -12,10 +12,15 @@ COPY . /go/src/github.com/grafana/loki
 WORKDIR /go/src/github.com/grafana/loki
 RUN GOARCH=$(cat /goarch) GOARM=$(cat /goarm) make clean && make promtail
 
-FROM alpine:3.9
+# Promtail requires debian as the base image to support systemd journal reading
+FROM debian:stretch-slim
 # tzdata required for the timestamp stage to work
-RUN apk add --update --no-cache ca-certificates tzdata
+RUN apt-get update && \
+    apt-get install -qy \
+      tzdata ca-certificates libsystemd-dev && \
+    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 COPY --from=build /go/src/github.com/grafana/loki/cmd/promtail/promtail /usr/bin/promtail
 COPY cmd/promtail/promtail-local-config.yaml /etc/promtail/local-config.yaml
 COPY cmd/promtail/promtail-docker-config.yaml /etc/promtail/docker-config.yaml
 ENTRYPOINT ["/usr/bin/promtail"]
+