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enhanced script to be able to support waiting for stateful sets #15

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0e79e00
enhanced script to be able to support waiting for stateful sets
Feb 22, 2019
26404d2
refactored back to only one commandline parameter including type and …
Apr 8, 2019
7c59ca3
minor fixes after review
Apr 11, 2019
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32 changes: 17 additions & 15 deletions wait-for-deployment
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Original file line number Diff line number Diff line change
Expand Up @@ -45,20 +45,21 @@ get_updated_replicas() {
get_deployment_jsonpath '{.status.updatedReplicas}'
}

get_available_replicas() {
get_deployment_jsonpath '{.status.availableReplicas}'
get_ready_replicas() {
get_deployment_jsonpath '{.status.readyReplicas}'
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Can you explain why you changed this from available to ready? Apologies, it's been a while since I looked into the exact logic.

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It's because readyReplicas is available for both deployment and stateful sets and availableReplicas only for deployments. So using readyReplicas allows us checking deployments and stateful sets the same way.

}

get_deployment_jsonpath() {
local -r jsonpath="$1"

kubectl --namespace "${namespace}" get deployment "${deployment}" -o "jsonpath=${jsonpath}"
kubectl --namespace "${namespace}" get "${type}" "${deployment}" -o "jsonpath=${jsonpath}"
}

display_usage_and_exit() {
echo "Usage: $(basename "$0") [-n <namespace>] [-t <timeout>] <deployment>" >&2
echo "Usage: $(basename "$0") [-n <namespace>] [-t <timeout>] <deployment|statefulset> <resource-name>" >&2
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Instead of requiring another parameter that would break existing users, how about expecting callers to define the type as a slash-delimited prefix to the resource name like

[<resource type>/]<resource name>

where <resource type> is optional and defaults to deployment. This would also be in line with what you see in k8s land / kubectl.

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I like this idea. Unfortunately I don't have time to implement and test it in the moment, it will take a while.

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No hurry on my end (how could I expect that anyway ;) ), take your time!

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I've pushed a new commit, changing the script back to using one commandline argument only. This should do it :)

echo "Arguments:" >&2
echo "deployment REQUIRED: The name of the deployment the script should wait on" >&2
echo "deployment|statefulset REQUIRED: the type of kubernetes resource to be waited for: deployment or statefulset, other types are not supported" >&2
echo "resource-name REQUIRED: The name of the deployment the script should wait on" >&2
echo "-n OPTIONAL: The namespace the deployment exists in, defaults is the 'default' namespace" >&2
echo "-t OPTIONAL: How long to wait for the deployment to be available, defaults to ${DEFAULT_TIMEOUT} seconds, must be greater than 0" >&2
exit 1
Expand All @@ -77,16 +78,17 @@ do
done

shift $((OPTIND-1))
if [ "$#" -ne 1 ] ; then
if [ "$#" -ne 2 ] ; then
display_usage_and_exit
fi
readonly deployment="$1"
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Could you re-apply the readonly declaration after line 92 (after which we do not need to mutate the variable again AFAIU)?

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Fixed :)

readonly type="$1"
readonly deployment="$2"

if [[ ${timeout} -le 0 ]]; then
display_usage_and_exit
fi

echo "Waiting for deployment of ${deployment} in namespace ${namespace} with a timeout ${timeout} seconds"
echo "Waiting for ${type} ${deployment} in namespace ${namespace} with a timeout ${timeout} seconds"

monitor_timeout $$ &
readonly timeout_monitor_pid=$!
Expand All @@ -96,7 +98,7 @@ trap 'kill -- -${timeout_monitor_pid}' EXIT #Stop timeout monitor
generation=$(get_generation); readonly generation
current_generation=$(get_observed_generation)

echo "Expected generation for deployment ${deployment}: ${generation}"
echo "Expected generation for ${type} ${deployment}: ${generation}"
while [[ ${current_generation} -lt ${generation} ]]; do
sleep .5
echo "Currently observed generation: ${current_generation}"
Expand All @@ -109,14 +111,14 @@ echo "Specified replicas: ${specified_replicas}"

current_replicas=$(get_replicas)
updated_replicas=$(get_updated_replicas)
available_replicas=$(get_available_replicas)
ready_replicas=$(get_ready_replicas)

while [[ ${updated_replicas} -lt ${specified_replicas} || ${current_replicas} -gt ${updated_replicas} || ${available_replicas} -lt ${updated_replicas} ]]; do
sleep .5
echo "current/updated/available replicas: ${current_replicas}/${updated_replicas}/${available_replicas}, waiting"
while [[ ${updated_replicas} -lt ${specified_replicas} || ${current_replicas} -gt ${updated_replicas} || ${ready_replicas} -lt ${updated_replicas} ]]; do
sleep 5
echo "${deployment} current/updated/ready replicas: ${current_replicas}/${updated_replicas}/${ready_replicas}, waiting"
current_replicas=$(get_replicas)
updated_replicas=$(get_updated_replicas)
available_replicas=$(get_available_replicas)
ready_replicas=$(get_ready_replicas)
done

echo "Deployment ${deployment} successful. All ${available_replicas} replicas are ready."
echo "Deployment/update of ${type} ${deployment} successful. All ${ready_replicas} replicas are ready."