use Python virtualenv also for main Makefile

* Makefile and tests/Makefile run Python scripts
* so have a global virtualenv to make sure all
  required Python modules are available

.gitignore

@@ -38,3 +38,5 @@ last_run
 
 *.test
 .DS_Store
+
+env

Makefile

@@ -109,18 +109,26 @@ coverage:
 benchmark:
 	$(GODEP) go test -short -bench=. ./...
 
+.PHONY: env
+env: env/bin/activate
+env/bin/activate: requirements.txt
+	test -d env || virtualenv env > /dev/null
+	. env/bin/activate && pip install -Ur requirements.txt > /dev/null
+	touch env/bin/activate
+
 .PHONY: gen
-gen:
+gen: env
 	./scripts/generate_gettingstarted.sh docs/gettingstarted.in.asciidoc docs/gettingstarted.asciidoc
-	python scripts/generate_template.py etc/fields.yml etc/packetbeat.template.json
-	python scripts/generate_field_docs.py etc/fields.yml docs/fields.asciidoc
+	. env/bin/activate && python scripts/generate_template.py   etc/fields.yml etc/packetbeat.template.json
+	. env/bin/activate && python scripts/generate_field_docs.py etc/fields.yml docs/fields.asciidoc
 
 .PHONY: clean
 clean:
 	-rm packetbeat
 	-rm packetbeat.test
 	-rm -r packetbeat-$(VERSION)
 	-rm -r coverage
+	-rm -r env
 
 # Generates packetbeat.test coverage testing binary
 packetbeat.test: $(GOFILES)

tests/.gitignore

@@ -5,4 +5,3 @@
 
 last_run
 run
-env

tests/Makefile

@@ -2,16 +2,11 @@ SHELL := /bin/bash
 PROCESSES ?= 4
 TIMEOUT ?= 30
 
-env: env/bin/activate
-env/bin/activate: requirements.txt
-	test -d env || virtualenv env > /dev/null
-	. env/bin/activate && pip install -Ur requirements.txt > /dev/null
-	touch env/bin/activate
-
 .PHONY: test
-test: env
+test:
 	make -C .. packetbeat.test
-	. env/bin/activate; nosetests --processes=${PROCESSES} --process-timeout=$(TIMEOUT)
+	make -C .. env
+	. ../env/bin/activate && nosetests --processes=${PROCESSES} --process-timeout=$(TIMEOUT)
 
 .PHONY: coverage
 coverage: test
@@ -25,6 +20,5 @@ coverage: test
 
 .PHONY: clean
 clean:
-	-rm -r env
 	-rm -r run
 	-rm last_run