Adds build package to allow discovering the correct name of the CLI

command. Can be configured at build time.

Signed-off-by: joshvanl <vleeuwenjoshua@gmail.com>

cmd/ctl/pkg/build/BUILD.bazel

@@ -0,0 +1,25 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["build.go"],
+    importpath = "github.com/jetstack/cert-manager/cmd/ctl/pkg/build",
+    visibility = ["//visibility:public"],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [
+        ":package-srcs",
+        "//cmd/ctl/pkg/build/commands:all-srcs",
+    ],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

cmd/ctl/pkg/build/build.go

@@ -0,0 +1,43 @@
+/*
+Copyright 2020 The cert-manager 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.
+*/
+
+package build
+
+import (
+	"bytes"
+	"text/template"
+)
+
+// name is the build time configurable name of the build (name of the target
+// binary name).
+var name = "kubectl cert-manager"
+
+// Name returns the build name.
+func Name() string {
+	return name
+}
+
+// WithTemplate returns a string that has the build name templated out with the
+// configured build name. Build name templates on '{{ .BuildName }}' variable.
+func WithTemplate(str string) string {
+	tmpl := template.Must(template.New("build-name").Parse(str))
+	var buf bytes.Buffer
+	if err := tmpl.Execute(&buf, struct{ BuildName string }{name}); err != nil {
+		// We panic here as it should never be possible that this template fails.
+		panic(err)
+	}
+	return buf.String()
+}