shell script that waits for a PlanetScale branch to be ready for use and increases retry times exponentially

wait-for-ps-branch-readiness.sh

#!/bin/sh

# shell script that waits for a PlanetScale branch to be ready for use and increases retry times exponentially

#  usage: wait-for-ps-branch-readiness.sh <db name> <branch name> <max retries>

function wait_for_branch_readiness {
    local retries=$1
    local db=$2
    local branch=$3
    local count=0

    echo "Checking if branch $branch is ready for use..."
    while true; do
        local raw_output=`pscale branch list $db --format json`
        # check return code, if not 0 then error
        if [ $? -ne 0 ]; then
            echo "Error: pscale branch list returned non-zero exit code $?: $raw_output"
            return 1
        fi
        local output=`echo $raw_output | jq ".[] | select(.name == \"$branch\") | .ready"`
        # test whether output is false, if so, increase wait timeout exponentially
        if [ "$output" == "false" ]; then
            local wait=$((2**$count))
            echo "Branch $branch is not ready yet. Retrying in $wait seconds..."
            sleep $wait
            count=$((count+1))
            if [ $retries -eq $count ]; then
                echo "Branch $branch is not ready after $retries retries. Exiting..."
                return 2
            fi
        elif [ "$output" == "true" ]; then
            echo "Branch $branch is ready for use."
            return 0
        else
            echo "Branch $branch in unknown status: $raw_output"
            return 3
        fi
    done
}

wait_for_branch_readiness $3 $1 $2