Feast Helm charts and build script (#289)

* Update Dockerfiles for core and serving for Feast 0.3

* Add example job store options for Redis in application.yaml

* Add script to publish feast helm chart

* Update default jvm options in CMD instruction in Feast Core Dockerfile

* Update installation path of grpc-health-probe in Feast serving Dockerfile

* Update feast charts for installing Feast with Helm
- Refer to README.md for more details how feast chart is structured and how to use it
- Feast Core and Feast Serving are subcharts that the parent Feast chart uses to install Feast. These subcharts optionally contains other dependencies such as Kafka, Postgresql or Redis. All these components can be enabled/disabled using the enabled flag in the Helm values.

* Update configmap.yaml for feast core
Override bootstrapServer value only if kafka is enabled and kafka.external is disabled

* Update configmap template for feast-serving
Support overriding Redis store host with LoadBalancer IP

* Set lower default delay time for readiness probes
- So pod scaling and startup is faster
- In most cases, Core and Feast should not need more than 15 seconds to start up

* Update Dockerfile for Feast Core
Include exploded/unpacked jar in the production image
To be used when staging files when submitting Dataflow jobs

* Allow users to specify nodePort in Helm values

.prow/scripts/sync-helm-charts.sh

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+
+# Script to sync local charts to remote helm repository in Google Cloud Storage
+# Copied from: https://github.com/helm/charts/blob/master/test/repo-sync.sh
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+log_error() {
+    printf '\e[31mERROR: %s\n\e[39m' "$1" >&2
+}
+
+# Assume working directory is Feast repository root folder
+repo_dir=infra/charts
+bucket=gs://feast-charts
+repo_url=https://feast-charts.storage.googleapis.com/
+sync_dir=/tmp/syncdir
+index_dir=/tmp/indexdir 
+
+rm -rf $sync_dir $index_dir
+
+echo "Syncing repo '$repo_dir'..."
+
+mkdir -p "$sync_dir"
+if ! gsutil cp "$bucket/index.yaml" "$index_dir/index.yaml"; then
+    log_error "Exiting because unable to copy index locally. Not safe to proceed."
+    exit 1
+fi
+
+exit_code=0
+
+for dir in "$repo_dir"/*; do
+    if helm dependency build "$dir"; then
+        helm package --destination "$sync_dir" "$dir"
+    else
+        log_error "Problem building dependencies. Skipping packaging of '$dir'."
+        exit_code=1
+    fi
+done
+
+if helm repo index --url "$repo_url" --merge "$index_dir/index.yaml" "$sync_dir"; then
+    # Move updated index.yaml to sync folder so we don't push the old one again
+    mv -f "$sync_dir/index.yaml" "$index_dir/index.yaml"
+
+    gsutil -m rsync "$sync_dir" "$bucket"
+
+    # Make sure index.yaml is synced last
+    gsutil cp "$index_dir/index.yaml" "$bucket"
+else
+    log_error "Exiting because unable to update index. Not safe to push update."
+    exit 1
+fi
+
+ls -l "$sync_dir"
+
+exit "$exit_code"