BigQuery Cost Estimator

1-README.md

BigQuery Cost Estimator

Get an estimate of how much a query is going to cost before you run it.

Instructions

1. Create a new bookmark with the contents of 2-bookmarklet as the URL.
2. Whenever you open a new BQ session, click the bookmarklet to attach the observer. You only have to do it once per session.

2-bookmarklet

javascript:!function(){const t=t=>1024*t,n=t=>t,r=t=>t/1024,e=t=>t/1024/1024,i=t=>t/1024/1024/1024,o=t=>t/1024/1024/1024/1024,s=s=>(s=>{if(s.endsWith(" B"))return o;if(s.endsWith(" KB"))return i;if(s.endsWith(" MB"))return e;if(s.endsWith(" GB"))return r;if(s.endsWith(" TB"))return n;if(s.endsWith(" PB"))return t;throw new Error(`could not determine units in "${s}"`)})(s)(parseFloat(s)),u=t=>t.firstChild&&3===t.firstChild.nodeType&&t.firstChild.textContent.includes("query will process"),d=t=>{const n=t.data;if((t=>t.includes("cost"))(n))return;const r=(t=>{const n=t.match(/\d+(\.\d+)? (B|KB|MB|GB|TB|PB)/);if(!n)throw new Error(`could not find a unit string in "${t}"`);return n[0]})(n);if(!r)return;const e=(t=>`$${(5*t).toFixed(2)}`)(s(r));t.data=((t,n)=>t.replace("when run",`and cost ${n} when run`))(n,e)},c=()=>{const t=((t,n)=>{const r=(t,n)=>{if(n(t))return t;if(!t.children)return null;for(const e of t.children){const t=r(e,n);if(t)return t}return null};return r(t,n)})(document.body,u);if(!t)return void setTimeout(c,1e3);const n=t.firstChild;if(!n)return void setTimeout(c,1e3);new MutationObserver(t=>{const n=t[0].target;d(n)}).observe(n,{characterData:!0,childList:!1,subtree:!1}),d(n)};c()}();

3-unminified.js

(function() {
    const treeFilter = (node, predicate) => {
        const walker = (node, predicate) => {
            if (predicate(node)) {
                return node;
            }

            if (!node.children) {
                return null;
            }

            for (const child of node.children) {
                const found = walker(child, predicate);
                if (found) {
                    return found;
                }
            }
            return null;
        };
        return walker(node, predicate);
    };

    const petabytesToTB = u => u * 1024;
    const terabytesToTB = u => u;
    const gigabytesToTB = u => u / 1024;
    const megabytesToTB = u => u / 1024 / 1024;
    const kilobytesToTB = u => u / 1024 / 1024 / 1024;
    const bytesToTB = u => u / 1024 / 1024 / 1024 / 1024;

    const extractUnitString = str => {
        const match = str.match(/\d+(\.\d+)? (B|KB|MB|GB|TB|PB)/);
        if (!match) {
            throw new Error(`could not find a unit string in "${str}"`);
        }
        return match[0];
    };

    const conversionFn = unitString => {
        if (unitString.endsWith(` B`)) return bytesToTB;
        if (unitString.endsWith(` KB`)) return kilobytesToTB;
        if (unitString.endsWith(` MB`)) return megabytesToTB;
        if (unitString.endsWith(` GB`)) return gigabytesToTB;
        if (unitString.endsWith(` TB`)) return terabytesToTB;
        if (unitString.endsWith(` PB`)) return petabytesToTB;
        throw new Error(`could not determine units in "${unitString}"`);
    };

    const unitStringToTB = unitString => conversionFn(unitString)(parseFloat(unitString));

    const tbToMoney = tb => `$${(tb * 5.0).toFixed(2)}`;

    const isQueryValidatorNode = e =>
        e.firstChild &&
        e.firstChild.nodeType === 3 &&
        e.firstChild.textContent.includes("query will process");

    const appendCostToQueryInfo = (queryInfo, cost) =>
        queryInfo.replace("when run", `and cost ${cost} when run`);

    const queryInfoContainsCost = queryInfo => queryInfo.includes("cost");

    const addCostToQueryInfoNode = textNode => {
        const queryInfo = textNode.data;

        if (queryInfoContainsCost(queryInfo)) {
            return;
        }

        const unitString = extractUnitString(queryInfo);
        if (!unitString) {
            return;
        }
        const cost = tbToMoney(unitStringToTB(unitString));
        textNode.data = appendCostToQueryInfo(queryInfo, cost);
    };

    const addMutationObserver = () => {
        const validatorNode = treeFilter(document.body, isQueryValidatorNode);
        if (!validatorNode) {
            setTimeout(addMutationObserver, 1000);
            return;
        }
        const textNode = validatorNode.firstChild;
        if (!textNode) {
            setTimeout(addMutationObserver, 1000);
            return;
        }
        const config = { characterData: true, childList: false, subtree: false };
        const callback = mutationList => {
            const textNode = mutationList[0].target;
            addCostToQueryInfoNode(textNode);
        };
        const observer = new MutationObserver(callback);
        observer.observe(textNode, config);
        addCostToQueryInfoNode(textNode);
    };

    addMutationObserver();
})();