add a Makefile

Adds the following human-facing targets:

- merge: builds and installs the merge binary
- config: creates a merged config using the merge binary
- test: tests the merged config using go test
- peribolos: clones a local copy of kubernetes/test-infra and installs
  the peribolos binary
- deploy: runs periobolos to deploy the merged config if tests pass
- clean: remove all intermediary configs and binaries

Overrideable env vars:

- GITHUB_TOKEN_PATH: value for --github-token-path passed to peribolos
- TEST_INFRA_PATH: set to location of a pre-existing clone of
  kubernetes/test-infra to avoid cloning a temporary copy

One way this differs from bazel is that we're not necessarily getting
the latest version of test-infra each time we run `make deploy` but I
don't foresee peribolos changing that frequently, and a `make clean` is
enough to get us back to "latest" state.

.gitignore

@@ -4,3 +4,4 @@
 /bazel-*
 .DS_Store
 .idea/
+_output/

Makefile

@@ -0,0 +1,86 @@
+# Copyright 2021 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+SHELL := /bin/bash
+
+# available for override
+GITHUB_TOKEN_PATH ?= /etc/github-token/token
+TEST_INFRA_PATH ?= $(OUTPUT_DIR)/tmp/test-infra
+
+# intentionally hardcoded list to ensure it's high friction to remove someone
+ADMINS = cblecker fejta idvoretskyi mrbobbytables nikhita spiffxp
+ORGS = $(shell find ./config -type d -mindepth 1 -maxdepth 1 | cut -d/ -f3)
+
+# use absolute path to ./_output, which is .gitignored
+OUTPUT_DIR := $(shell pwd)/_output
+OUTPUT_BIN_DIR := $(OUTPUT_DIR)/bin
+
+MERGE_CMD := $(OUTPUT_BIN_DIR)/merge
+PERIBOLOS_CMD := $(OUTPUT_BIN_DIR)/peribolos
+
+MERGED_CONFIG := $(OUTPUT_DIR)/gen-config.yaml
+
+# convenience targets for humans
+.PHONY: clean
+clean:
+	rm -rf $(OUTPUT_DIR)
+
+.PHONY: build
+build:
+	go build ./...
+
+.PHONY: merge
+merge: $(MERGE_CMD)
+
+.PHONY: config
+config: $(MERGED_CONFIG)
+
+.PHONY: peribolos
+peribolos: $(PERIBOLOS_CMD)
+
+.PHONY: test
+test: config
+	go test ./... --config=$(MERGED_CONFIG)
+
+.PHONY: deploy # --confirm
+deploy: config test peribolos
+	$(PERIBOLOS_CMD) \
+		--config-path $(MERGED_CONFIG) \
+		--fix-org \
+		--fix-org-members \
+		--fix-teams \
+		--fix-team-members \
+		--github-token-path=$(GITHUB_TOKEN_PATH) \
+		$(patsubst %, --required-admins=%, $(ADMINS)) \
+		$@
+
+# actual targets that only get built if they don't already exist
+$(MERGE_CMD):
+	mkdir -p "$(OUTPUT_BIN_DIR)"
+	go build -v -o "$(OUTPUT_BIN_DIR)" ./cmd/merge
+
+$(MERGED_CONFIG): $(MERGE_CMD) config/**/*.yaml
+	mkdir -p "$(OUTPUT_DIR)"
+	$(MERGE_CMD) \
+		--merge-teams \
+		$(shell for o in $(ORGS); do echo "--org-part=$$o=config/$$o/org.yaml"; done) \
+		> $(MERGED_CONFIG)
+
+$(TEST_INFRA_PATH):
+	mkdir -p $(TEST_INFRA_PATH)
+	git clone --depth=1 https://github.com/kubernetes/test-infra $(TEST_INFRA_PATH)
+
+$(PERIBOLOS_CMD): $(TEST_INFRA_PATH)
+	cd $(TEST_INFRA_PATH) && \
+		go build -v -o $(PERIBOLOS_CMD) ./prow/cmd/peribolos

config/config_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package config
 
 import (
+	"flag"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -31,6 +32,31 @@ import (
 	"github.com/ghodss/yaml"
 )
 
+var configPath = flag.String("config", "config.yaml", "Path to generated config")
+
+var cfg org.FullConfig
+
+func TestMain(m *testing.M) {
+	flag.Parse()
+	if *configPath == "" {
+		fmt.Println("--config must be set")
+		os.Exit(1)
+	}
+
+	raw, err := ioutil.ReadFile(*configPath)
+	if err != nil {
+		fmt.Printf("cannot read generated config.yaml from %s: %v\n", *configPath, err)
+		os.Exit(1)
+	}
+
+	if err := yaml.Unmarshal(raw, &cfg); err != nil {
+		fmt.Printf("cannot unmarshal generated config.yaml from %s: %v\n", *configPath, err)
+		os.Exit(1)
+	}
+
+	os.Exit(m.Run())
+}
+
 type owners struct {
 	Reviewers []string `json:"reviewers,omitempty"`
 	Approvers []string `json:"approvers"`
@@ -191,11 +217,6 @@ func testOrg(targetDir string, t *testing.T) {
 }
 
 func TestAllOrgs(t *testing.T) {
-	raw, err := ioutil.ReadFile("config.yaml")
-	var cfg org.FullConfig
-	if err := yaml.Unmarshal(raw, &cfg); err != nil {
-		t.Fatalf("cannot read config.yaml from //config:gen-config.yaml: %v", err)
-	}
 	f, err := os.Open(".")
 	if err != nil {
 		t.Fatalf("cannot read config: %v", err)