Generic shell functions for common k8s commands

k8s-instance-funcs.sh

## some generic functions based on `app.kubernetes.io/instance` label

# list pods including instance label
function k8s.pod() {
  kubectl get pod -L app.kubernetes.io/instance
}

# list deployments including instance label
function k8s.deployment() {
  kubectl get deployment -L app.kubernetes.io/instance
}

# get service pod name by instance
function k8s.instance.servicePod() {
  [ -z "$1" ] && {
    echo "Usage: ${FUNCNAME[0]} <app.kubernetes.io/instance>"
    return
  }
  kubectl get pod -l app.kubernetes.io/instance=$1 -o jsonpath="{ .items[0].metadata.name }"
}

# get deployment name by instance
function k8s.instance.deployment() {
  [ -z "$1" ] && {
    echo "Usage: ${FUNCNAME[0]} <app.kubernetes.io/instance>"
    return
  }
  kubectl get deployment -l app.kubernetes.io/instance=$1 -o jsonpath="{ .items[0].metadata.name }"
}

# get replicaset name by instance
function k8s.instance.replicaset() {
  [ -z "$1" ] && {
    echo "Usage: ${FUNCNAME[0]} <app.kubernetes.io/instance>"
    return
  }
  kubectl get replicaset -l app.kubernetes.io/instance=$1 -o jsonpath="{ .items[0].metadata.name }"
}

# tail logs of a single pod by instance
function k8s.instance.tailLogs() {
  [ -z "$1" ] && {
    echo "Usage: ${FUNCNAME[0]} <instance>"
    return
  }
  kubectl logs --tail 500 -f $(k8s.instance.servicePod "$1")
}

# scale replicaset by instance
function k8s.instance.scale() {
  [ -z "$2" ] && {
    echo "Usage: ${FUNCNAME[0]} <instance> <replicas>"
    return
  }
  echo "Scaling $(k8s.instance.replicaset "$1") to $2"
  kubectl scale replicaset/$(k8s.instance.replicaset "$1") --replicas $2
}

# scale deployment to 0 = stop, 1 = start
function k8s.instance.stop() {
  [ -z "$1" ] && {
    echo "Usage: ${FUNCNAME[0]} <instance>"
    return
  }
  echo "Scaling $(k8s.instance.deployment "$1") to $2"
  kubectl scale deployment/$(k8s.instance.deployment "$1") --replicas 0
}
function k8s.instance.start() {
  [ -z "$1" ] && {
    echo "Usage: ${FUNCNAME[0]} <instance>"
    return
  }
  echo "Scaling $(k8s.instance.deployment "$1") to $2"
  kubectl scale deployment/$(k8s.instance.deployment "$1") --replicas 1
}

# get variables of first container
function k8s.instance.variable() {
  [ -z "$1" ] && {
    echo "Usage: ${FUNCNAME[0]} <instance>"
    return
  }
  kubectl get deployment $(k8s.instance.deployment "$1") \
    -o jsonpath="{ .spec.template.spec.containers[0].env }"
}
# set variable to given value
function k8s.instance.variable.set() {
  [ -z "$3" ] && {
    echo "Usage: ${FUNCNAME[0]} <instance> <variable_name> <variable_value>"
    return
  }
  index=$(kubectl get deployment $(k8s.instance.deployment "$1") -o json \
    | jq '.spec.template.spec.containers[].env|map(.name == "'$2'")|index(true)')
  [ "null" == "$index" ] && {
    echo "Error: variable '$2' not found"
    return
  }
  kubectl patch deployment $(k8s.instance.deployment "$1") --type=json \
    -p='[{"op":"replace", "path":"/spec/template/spec/containers/0/env/'$index'/value", "value": "'$3'"}]'
}