nats.sh

#!/bin/bash
# Copyright 2021-2023 H2020 TeraFlow (https://www.teraflow-h2020.eu/)
#
# 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.

########################################################################################################################
# Read deployment settings
########################################################################################################################

# If not already set, set the namespace where NATS will be deployed.
export NATS_NAMESPACE=${NATS_NAMESPACE:-"nats"}

# If not already set, set the name of the secret where NATS data and credentials will be stored.
export NATS_SECRET_NAME=${NATS_SECRET_NAME:-"nats-data"}

# If not already set, set the namespace where the secret containing NATS data and credentials will be stored.
export NATS_SECRET_NAMESPACE=${NATS_SECRET_NAMESPACE:-"tfs"}

# If not already set, disable flag for re-deploying NATS from scratch.
# WARNING: ACTIVATING THIS FLAG IMPLIES LOOSING THE MESSAGE BROKER INFORMATION!
# If NATS_REDEPLOY is "YES", the message broker will be dropped while checking/deploying NATS.
export NATS_REDEPLOY=${NATS_REDEPLOY:-""}

########################################################################################################################
# Automated steps start here
########################################################################################################################

# Constants
TMP_FOLDER="./tmp"
NATS_MANIFESTS_PATH="manifests/nats"

# Create a tmp folder for files modified during the deployment
TMP_MANIFESTS_FOLDER="$TMP_FOLDER/manifests"
mkdir -p $TMP_MANIFESTS_FOLDER

function nats_deploy_single() {
    echo "NATS Namespace"
    echo ">>> Create NATS Namespace (if missing)"
    kubectl create namespace ${NATS_NAMESPACE}
    echo

    echo "Add NATS Helm Chart"
    helm3 repo add nats https://nats-io.github.io/k8s/helm/charts/
    echo

    echo "Install NATS (single-node)"
    echo ">>> Checking if NATS is deployed..."
    if kubectl get --namespace ${NATS_NAMESPACE} statefulset/nats &> /dev/null; then
        echo ">>> NATS is present; skipping step."
    else
        echo ">>> Deploy NATS"
        helm3 install nats nats/nats --namespace ${NATS_NAMESPACE} --set nats.image.tag=2.9-alpine

        echo ">>> Waiting NATS statefulset to be created..."
        while ! kubectl get --namespace ${NATS_NAMESPACE} statefulset/nats &> /dev/null; do
            printf "%c" "."
            sleep 1
        done

        # Wait for statefulset condition "Available=True" does not work
        # Wait for statefulset condition "jsonpath='{.status.readyReplicas}'=3" throws error:
        #   "error: readyReplicas is not found"
        # Workaround: Check the pods are ready
        #echo ">>> NATS statefulset created. Waiting for readiness condition..."
        #kubectl wait --namespace  ${NATS_NAMESPACE} --for=condition=Available=True --timeout=300s statefulset/nats
        #kubectl wait --namespace ${NATS_NAMESPACE} --for=jsonpath='{.status.readyReplicas}'=3 --timeout=300s \
        #    statefulset/nats
        echo ">>> NATS statefulset created. Waiting NATS pods to be created..."
        while ! kubectl get --namespace ${NATS_NAMESPACE} pod/nats-0 &> /dev/null; do
            printf "%c" "."
            sleep 1
        done
        kubectl wait --namespace ${NATS_NAMESPACE} --for=condition=Ready --timeout=300s pod/nats-0
    fi
    echo

    echo "NATS Port Mapping"
    echo ">>> Expose NATS Client port (4222)"
    NATS_CLIENT_PORT=$(kubectl --namespace ${NATS_NAMESPACE} get service nats -o 'jsonpath={.spec.ports[?(@.name=="client")].port}')
    PATCH='{"data": {"'${NATS_CLIENT_PORT}'": "'${NATS_NAMESPACE}'/nats:'${NATS_CLIENT_PORT}'"}}'
    kubectl patch configmap nginx-ingress-tcp-microk8s-conf --namespace ingress --patch "${PATCH}"

    PORT_MAP='{"containerPort": '${NATS_CLIENT_PORT}', "hostPort": '${NATS_CLIENT_PORT}'}'
    CONTAINER='{"name": "nginx-ingress-microk8s", "ports": ['${PORT_MAP}']}'
    PATCH='{"spec": {"template": {"spec": {"containers": ['${CONTAINER}']}}}}'
    kubectl patch daemonset nginx-ingress-microk8s-controller --namespace ingress --patch "${PATCH}"
    echo

    echo ">>> Expose NATS HTTP Mgmt GUI port (8222)"
    NATS_GUI_PORT=$(kubectl --namespace ${NATS_NAMESPACE} get service nats -o 'jsonpath={.spec.ports[?(@.name=="monitor")].port}')
    PATCH='{"data": {"'${NATS_GUI_PORT}'": "'${NATS_NAMESPACE}'/nats:'${NATS_GUI_PORT}'"}}'
    kubectl patch configmap nginx-ingress-tcp-microk8s-conf --namespace ingress --patch "${PATCH}"

    PORT_MAP='{"containerPort": '${NATS_GUI_PORT}', "hostPort": '${NATS_GUI_PORT}'}'
    CONTAINER='{"name": "nginx-ingress-microk8s", "ports": ['${PORT_MAP}']}'
    PATCH='{"spec": {"template": {"spec": {"containers": ['${CONTAINER}']}}}}'
    kubectl patch daemonset nginx-ingress-microk8s-controller --namespace ingress --patch "${PATCH}"
    echo

    echo "Create secret with NATS data"
    kubectl create secret generic ${NATS_SECRET_NAME} --namespace ${NATS_SECRET_NAMESPACE} --type='Opaque' \
        --from-literal=NATS_NAMESPACE=${NATS_NAMESPACE} \
        --from-literal=NATS_CLIENT_PORT=${NATS_CLIENT_PORT} \
        --from-literal=NATS_GUI_PORT=${NATS_GUI_PORT}

    kubectl get all --all-namespaces
}

function nats_undeploy_single() {
    echo "Delete secret with NATS data"
    kubectl delete secret ${NATS_SECRET_NAME} --namespace ${NATS_SECRET_NAMESPACE} --ignore-not-found
    echo

    echo "NATS"
    echo ">>> Checking if NATS is deployed..."
    if kubectl get --namespace ${NATS_NAMESPACE} statefulset/nats &> /dev/null; then
        echo ">>> Undeploy NATS"
        helm3 uninstall --namespace ${NATS_NAMESPACE} nats
    else
        echo ">>> NATS is not present; skipping step."
    fi
    echo

    echo "NATS Namespace"
    echo ">>> Delete NATS Namespace (if exists)"
    kubectl delete namespace ${NATS_NAMESPACE} --ignore-not-found
    echo
}

if [ "$NATS_REDEPLOY" == "YES" ]; then
    nats_undeploy_single
fi

nats_deploy_single