I have a very large multi section script with a LOT of loops and some recursion in it. When I run it on a Very Large dataset, the script will simply stop running. It stops with a 0 exit code. It VERY clearly does not actually finish running…it just…stops.
asyncLib.waterfall([
getPronghornToken,
saveSchedulers,
saveServices,
populateServRefs,
saveServiceGroups,
saveNetworks,
populateNetRefs, //never actually gets out of this function. Just exits with code 0
saveNetworkGroups,
saveRuleGroups,
fetchRuleGroupIds,
populateRules,
saveRules,
getPolicyId,
linkRuleGroup
], function (err, result) {
if (err){
console.error("Something bad happened. Please try again");
process.exit(1);
}
console.log("done");
});
What I’m looking for: Why would a script just stop mid loop and exit with a 0 code?
Note: Alternate code.
getPronghornToken((err, token) => {
if(err) {
console.log("Error occured getPronghornToken");
throw err;
}
saveSchedulers(token, (err, token) => {
if(err) {
console.log("Error occured saveSchedulers");
throw err;
}
saveServices(token, (err, token) => {
if(err) {
console.log("Error occured saveServices");
throw err;
}
populateServRefs(token, (err, token) => {
if(err) {
console.log("Error occured populateServRefs");
throw err;
}
saveServiceGroups(token, (err, token) => {
if(err) {
console.log("Error occured saveServiceGroups");
throw err;
}
saveNetworks(token, (err, token) => {
if(err) {
console.log("Error occured saveNetworks");
throw err;
}
populateNetRefs(token, (err, token) => {
if(err) {
console.log("Error occured populateNetRefs");
throw err;
}
saveNetworkGroups(token, (err, token) => {
if(err) {
console.log("Error occured saveNetworkGroups");
throw err;
}
saveRuleGroups(token, (err, token) => {
if(err) {
console.log("Error occured saveRuleGroups");
throw err;
}
fetchRuleGroupIds(token, (err, token) => {
if(err) {
console.log("Error occured fetchRuleGroupIds");
throw err;
}
populateRules(token, (err, token) => {
if(err) {
console.log("Error occured populateRules");
throw err;
}
saveRules(token, (err, token) => {
if(err) {
console.log("Error occured saveRules");
throw err;
}
getPolicyId(token, (err, token) => {
if(err) {
console.log("Error occured getPolicyId");
throw err;
}
linkRuleGroup(token, (err, token) => {
if(err) {
console.log("Error occured linkRuleGroup");
throw err;
}
console.log("Successfully installed all files");
});
});
});
});
});
});
});
});
});
});
});
});
});
});
No errors thrown. Does NOT print out the innermost message. Callback pattern verified.
Last Function running looks like this:
async function populateNetRefs(token, callback) {
//let newNetRefs = [];
for(let index = 0; index < networkGroups.length; index++) {
if (index >= networkGroups.length) {
console.log("Net Refs Finished")
return callback(null, token);
}
let networkGroup = networkGroups[index];
try {
console.log(`fetching network number: ${index+1} / ${networkGroups.length}`);
let newNetRefs = await fetchNetId(token, networkGroup._netRefs);
networkGroup._netRefs = newNetRefs;
} catch (err) {
console.log(`An error occurrent fetching the network id for index ${index+1} / ${networkGroups.length}: ${err}`);
}
}
}
The Inner Function:
function fetchNetId(token, _netRefs) {
let fetchFinished = 0;
let newNetRefs = [];
let errCount = 1;
console.log("ZZ Fetchid Start ZZ");
return new Promise((resolve, reject) => {
_netRefs.forEach(function(_netRef) {
let options = {
//Required to be hidden
};
let req = https.request(options, (res) => {
let reply = [];
res.setEncoding('utf8');
res.on('data', (chunk) => {
console.log("YY GET DATA CHUNK YY");
reply.push(chunk);
});
res.on('end', () => {
fetchFinished++;
console.log("Reply is : " + reply.join());
//There is some logic in this spot. Not for you.
console.log("fetchFinished is: " + fetchFinished + ", size is: " + _netRefs.length);
if (fetchFinished === _netRefs.length) {
resolve(newNetRefs);
}
});
});
req.on('error', (e) => {
console.error(`problem with request ${errCount++}: ${e.message}`);
//reject(e);
});
let body = JSON.stringify({
"options" : {
"start": 0,
"limit": 5,
"sort": {
},
"filter": {
"name":{"$eq":_netRef}
}
}
});
console.log("XX Sending Request XX");
req.write(body);
req.end();
});
});
}
BEHAVIOR UPDATE – More Console Logs
Here’s the end of the console log:
fetching network number: 49 / 711
ZZ Fetchid Start ZZ
XX Sending Request XX
XX Sending Request XX
YY GET DATA CHUNK YY
Reply is : {hidden from you}
TroubleShootingDias: some guid
fetchFinished is: 1, size is: 2
YY GET DATA CHUNK YY
Reply is : {hidden from you}
TroubleShootingDias: some guid
fetchFinished is: 2, size is: 2
fetch success
fetching network number: 50 / 711
ZZ Fetchid Start ZZ
[vagrant@vag-host1 space-parser]$
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Answer
Actual solution to the problem: If the array is empty, then the promise never resolves. Added an empty check to the very top, before the loop.
function fetchNetId(token, _netRefs) {
let fetchFinished = 0;
let newNetRefs = [];
let errCount = 1;
console.log("ZZ Fetchid Start ZZ");
return new Promise((resolve, reject) => {
if(_netRefs.length === 0) return resolve([]) // <==============
_netRefs.forEach(function(_netRef) {
let options = {
//Required to be hidden
};
let req = https.request(options, (res) => {
let reply = [];
res.setEncoding('utf8');
res.on('data', (chunk) => {
console.log("YY GET DATA CHUNK YY");
reply.push(chunk);
});
//........