Encode git version info into binary and user agent

Signed-off-by: Monis Khan <mok@vmware.com>

Dockerfile

@@ -5,7 +5,7 @@ ARG ACCESS_TOKEN_USR="nothing"
 ARG ACCESS_TOKEN_PWD="nothing"
 
 # git is required to fetch go dependencies
-RUN apk add --no-cache ca-certificates git
+RUN apk add --no-cache ca-certificates git bash
 
 # Create a netrc file using the credentials specified using --build-arg
 RUN printf "machine github.com\n\
@@ -28,15 +28,15 @@ RUN go mod download
 # Copy the source code
 COPY . .
 # Build the executable binary
-RUN GOOS=linux GOARCH=amd64 go build -o out ./...
+RUN GOOS=linux GOARCH=amd64 go build -ldflags "$(hack/get-ldflags.sh)" -o out ./...
 
 FROM alpine:latest
 # Install CA certs and some tools for debugging
 RUN apk --update --no-cache add ca-certificates bash curl
 WORKDIR /root/
 # Copy the binary from the build-env stage
-COPY --from=build-env /work/out/placeholder-name app
+COPY --from=build-env /work/out/placeholder-name placeholder-name
 # Document the port
 EXPOSE 8080
 # Set the command
-CMD ["./app"]
+CMD ["./placeholder-name"]

cmd/placeholder-name/main.go

@@ -8,10 +8,15 @@ package main
 import (
 	"os"
 
+	"k8s.io/client-go/pkg/version"
+	"k8s.io/client-go/rest"
+	"k8s.io/klog/v2"
+
 	"github.com/suzerain-io/placeholder-name/cmd/placeholder-name/app"
 )
 
 func main() {
+	klog.Infof("Running %s at %#v", rest.DefaultKubernetesUserAgent(), version.Get())
 	if err := app.New(os.Args[1:], os.Stdout, os.Stderr).Run(); err != nil {
 		os.Exit(1)
 	}

deploy/deployment.yaml

@@ -55,7 +55,7 @@ spec:
           #@ end
           imagePullPolicy: IfNotPresent
           command:
-            - ./app
+            - ./placeholder-name
           args:
             - --config=/etc/config/placeholder-config.yaml
             - --downward-api-path=/etc/podinfo

go.mod

@@ -14,6 +14,7 @@ require (
 	k8s.io/apimachinery v0.19.0-rc.0
 	k8s.io/apiserver v0.19.0-rc.0
 	k8s.io/client-go v0.19.0-rc.0
+	k8s.io/klog/v2 v2.2.0
 	k8s.io/kube-aggregator v0.19.0-rc.0
 	k8s.io/utils v0.0.0-20200619165400-6e3d28b6ed19
 	sigs.k8s.io/yaml v1.2.0

hack/get-ldflags.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+KUBE_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
+source "${KUBE_ROOT}/hack/lib/version.sh"
+
+kube::version::ldflags

hack/lib/version.sh

@@ -0,0 +1,182 @@
+#!/usr/bin/env bash
+
+# Copyright 2014 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.
+
+# -----------------------------------------------------------------------------
+# Version management helpers.  These functions help to set, save and load the
+# following variables:
+#
+#    KUBE_GIT_COMMIT - The git commit id corresponding to this
+#          source code.
+#    KUBE_GIT_TREE_STATE - "clean" indicates no changes since the git commit id
+#        "dirty" indicates source code changes after the git commit id
+#        "archive" indicates the tree was produced by 'git archive'
+#    KUBE_GIT_VERSION - "vX.Y" used to indicate the last release version.
+#    KUBE_GIT_MAJOR - The major part of the version
+#    KUBE_GIT_MINOR - The minor component of the version
+
+# Grovels through git to set a set of env variables.
+#
+# If KUBE_GIT_VERSION_FILE, this function will load from that file instead of
+# querying git.
+kube::version::get_version_vars() {
+  if [[ -n ${KUBE_GIT_VERSION_FILE-} ]]; then
+    kube::version::load_version_vars "${KUBE_GIT_VERSION_FILE}"
+    return
+  fi
+
+  # If the kubernetes source was exported through git archive, then
+  # we likely don't have a git tree, but these magic values may be filled in.
+  # shellcheck disable=SC2016,SC2050
+  # Disabled as we're not expanding these at runtime, but rather expecting
+  # that another tool may have expanded these and rewritten the source (!)
+  if [[ '$Format:%%$' == "%" ]]; then
+    KUBE_GIT_COMMIT='$Format:%H$'
+    KUBE_GIT_TREE_STATE="archive"
+    # When a 'git archive' is exported, the '$Format:%D$' below will look
+    # something like 'HEAD -> release-1.8, tag: v1.8.3' where then 'tag: '
+    # can be extracted from it.
+    if [[ '$Format:%D$' =~ tag:\ (v[^ ,]+) ]]; then
+     KUBE_GIT_VERSION="${BASH_REMATCH[1]}"
+    fi
+  fi
+
+  local git=(git --work-tree "${KUBE_ROOT}")
+
+  if [[ -n ${KUBE_GIT_COMMIT-} ]] || KUBE_GIT_COMMIT=$("${git[@]}" rev-parse "HEAD^{commit}" 2>/dev/null); then
+    if [[ -z ${KUBE_GIT_TREE_STATE-} ]]; then
+      # Check if the tree is dirty.  default to dirty
+      if git_status=$("${git[@]}" status --porcelain 2>/dev/null) && [[ -z ${git_status} ]]; then
+        KUBE_GIT_TREE_STATE="clean"
+      else
+        KUBE_GIT_TREE_STATE="dirty"
+      fi
+    fi
+
+    # Use git describe to find the version based on tags.
+    if [[ -n ${KUBE_GIT_VERSION-} ]] || KUBE_GIT_VERSION=$("${git[@]}" describe --tags --match='v*' --abbrev=14 "${KUBE_GIT_COMMIT}^{commit}" 2>/dev/null); then
+      # This translates the "git describe" to an actual semver.org
+      # compatible semantic version that looks something like this:
+      #   v1.1.0-alpha.0.6+84c76d1142ea4d
+      #
+      # TODO: We continue calling this "git version" because so many
+      # downstream consumers are expecting it there.
+      #
+      # These regexes are painful enough in sed...
+      # We don't want to do them in pure shell, so disable SC2001
+      # shellcheck disable=SC2001
+      DASHES_IN_VERSION=$(echo "${KUBE_GIT_VERSION}" | sed "s/[^-]//g")
+      if [[ "${DASHES_IN_VERSION}" == "---" ]] ; then
+        # shellcheck disable=SC2001
+        # We have distance to subversion (v1.1.0-subversion-1-gCommitHash)
+        KUBE_GIT_VERSION=$(echo "${KUBE_GIT_VERSION}" | sed "s/-\([0-9]\{1,\}\)-g\([0-9a-f]\{14\}\)$/.\1\+\2/")
+      elif [[ "${DASHES_IN_VERSION}" == "--" ]] ; then
+        # shellcheck disable=SC2001
+        # We have distance to base tag (v1.1.0-1-gCommitHash)
+        KUBE_GIT_VERSION=$(echo "${KUBE_GIT_VERSION}" | sed "s/-g\([0-9a-f]\{14\}\)$/+\1/")
+      fi
+      if [[ "${KUBE_GIT_TREE_STATE}" == "dirty" ]]; then
+        # git describe --dirty only considers changes to existing files, but
+        # that is problematic since new untracked .go files affect the build,
+        # so use our idea of "dirty" from git status instead.
+        KUBE_GIT_VERSION+="-dirty"
+      fi
+
+
+      # Try to match the "git describe" output to a regex to try to extract
+      # the "major" and "minor" versions and whether this is the exact tagged
+      # version or whether the tree is between two tagged versions.
+      if [[ "${KUBE_GIT_VERSION}" =~ ^v([0-9]+)\.([0-9]+)(\.[0-9]+)?([-].*)?([+].*)?$ ]]; then
+        KUBE_GIT_MAJOR=${BASH_REMATCH[1]}
+        KUBE_GIT_MINOR=${BASH_REMATCH[2]}
+        if [[ -n "${BASH_REMATCH[4]}" ]]; then
+          KUBE_GIT_MINOR+="+"
+        fi
+      fi
+
+      # If KUBE_GIT_VERSION is not a valid Semantic Version, then refuse to build.
+      if ! [[ "${KUBE_GIT_VERSION}" =~ ^v([0-9]+)\.([0-9]+)(\.[0-9]+)?(-[0-9A-Za-z.-]+)?(\+[0-9A-Za-z.-]+)?$ ]]; then
+          echo "KUBE_GIT_VERSION should be a valid Semantic Version. Current value: ${KUBE_GIT_VERSION}"
+          echo "Please see more details here: https://semver.org"
+          exit 1
+      fi
+    fi
+  fi
+}
+
+# Saves the environment flags to $1
+kube::version::save_version_vars() {
+  local version_file=${1-}
+  [[ -n ${version_file} ]] || {
+    echo "!!! Internal error.  No file specified in kube::version::save_version_vars"
+    return 1
+  }
+
+  cat <<EOF >"${version_file}"
+KUBE_GIT_COMMIT='${KUBE_GIT_COMMIT-}'
+KUBE_GIT_TREE_STATE='${KUBE_GIT_TREE_STATE-}'
+KUBE_GIT_VERSION='${KUBE_GIT_VERSION-}'
+KUBE_GIT_MAJOR='${KUBE_GIT_MAJOR-}'
+KUBE_GIT_MINOR='${KUBE_GIT_MINOR-}'
+EOF
+}
+
+# Loads up the version variables from file $1
+kube::version::load_version_vars() {
+  local version_file=${1-}
+  [[ -n ${version_file} ]] || {
+    echo "!!! Internal error.  No file specified in kube::version::load_version_vars"
+    return 1
+  }
+
+  source "${version_file}"
+}
+
+# Prints the value that needs to be passed to the -ldflags parameter of go build
+# in order to set the Kubernetes based on the git tree status.
+# IMPORTANT: if you update any of these, also update the lists in
+# pkg/version/def.bzl and hack/print-workspace-status.sh.
+kube::version::ldflags() {
+  kube::version::get_version_vars
+
+  local -a ldflags
+  function add_ldflag() {
+    local key=${1}
+    local val=${2}
+    # If you update these, also update the list component-base/version/def.bzl.
+    ldflags+=(
+      "-X 'k8s.io/client-go/pkg/version.${key}=${val}'"
+      "-X 'k8s.io/component-base/version.${key}=${val}'"
+    )
+  }
+
+  add_ldflag "buildDate" "$(date ${SOURCE_DATE_EPOCH:+"--date=@${SOURCE_DATE_EPOCH}"} -u +'%Y-%m-%dT%H:%M:%SZ')"
+  if [[ -n ${KUBE_GIT_COMMIT-} ]]; then
+    add_ldflag "gitCommit" "${KUBE_GIT_COMMIT}"
+    add_ldflag "gitTreeState" "${KUBE_GIT_TREE_STATE}"
+  fi
+
+  if [[ -n ${KUBE_GIT_VERSION-} ]]; then
+    add_ldflag "gitVersion" "${KUBE_GIT_VERSION}"
+  fi
+
+  if [[ -n ${KUBE_GIT_MAJOR-} && -n ${KUBE_GIT_MINOR-} ]]; then
+    add_ldflag "gitMajor" "${KUBE_GIT_MAJOR}"
+    add_ldflag "gitMinor" "${KUBE_GIT_MINOR}"
+  fi
+
+  # The -ldflags parameter takes a single string, so join the output.
+  echo "${ldflags[*]-}"
+}

hack/update.sh

@@ -2,4 +2,4 @@
 set -e
 
 go mod tidy
-go run github.com/golangci/golangci-lint/cmd/golangci-lint run ./... --fix
+go run github.com/golangci/golangci-lint/cmd/golangci-lint run ./... --fix --timeout=10m

hack/verify.sh

@@ -1,4 +1,4 @@
 #!/bin/bash
 set -e
 
-go run github.com/golangci/golangci-lint/cmd/golangci-lint run ./... --modules-download-mode=readonly
+go run github.com/golangci/golangci-lint/cmd/golangci-lint run ./... --modules-download-mode=readonly --timeout=10m