NodeJS code is not waiting for function completion
I am creating an Excel file with a Lambda function that is later sent by E-Mail.
The Excel is filled with data before and is then stored like this(With the excel4node nom package):
console.log("Before print");
var test2 = await workbook.write(path, function(err, stats)
console.log("Excel written");
if (err)
console.error(err);
else
console.log(stats); // Prints out an instance of a node.js fs.Stats object
);
console.log("After print");
The code works sometimes. The problem is the following code is not waiting until the excel is written and the E-Mail cannot find the attachment.
How can I make my Lambda function wait until the excel is written to disk?
node.js asynchronous
edited Nov 16 '18 at 1:30
jhpratt
3,184102433
asked Nov 16 '18 at 0:58
AlexAlex
5610
add a comment |
I am creating an Excel file with a Lambda function that is later sent by E-Mail.
The Excel is filled with data before and is then stored like this(With the excel4node nom package):
console.log("Before print");
var test2 = await workbook.write(path, function(err, stats)
console.log("Excel written");
if (err)
console.error(err);
else
console.log(stats); // Prints out an instance of a node.js fs.Stats object
);
console.log("After print");
The code works sometimes. The problem is the following code is not waiting until the excel is written and the E-Mail cannot find the attachment.
How can I make my Lambda function wait until the excel is written to disk?
node.js asynchronous
edited Nov 16 '18 at 1:30
jhpratt
3,184102433
asked Nov 16 '18 at 0:58
AlexAlex
5610
You probably want to look at How do I convert an existing callback API to promises?
– Felix Kling
Nov 16 '18 at 1:11
add a comment |
I am creating an Excel file with a Lambda function that is later sent by E-Mail.
The Excel is filled with data before and is then stored like this(With the excel4node nom package):
console.log("Before print");
var test2 = await workbook.write(path, function(err, stats)
console.log("Excel written");
if (err)
console.error(err);
else
console.log(stats); // Prints out an instance of a node.js fs.Stats object
);
console.log("After print");
The code works sometimes. The problem is the following code is not waiting until the excel is written and the E-Mail cannot find the attachment.
How can I make my Lambda function wait until the excel is written to disk?
node.js asynchronous
edited Nov 16 '18 at 1:30
jhpratt
3,184102433
asked Nov 16 '18 at 0:58
AlexAlex
5610
I am creating an Excel file with a Lambda function that is later sent by E-Mail.
The Excel is filled with data before and is then stored like this(With the excel4node nom package):
console.log("Before print");
var test2 = await workbook.write(path, function(err, stats)
console.log("Excel written");
if (err)
console.error(err);
else
console.log(stats); // Prints out an instance of a node.js fs.Stats object
);
console.log("After print");
The code works sometimes. The problem is the following code is not waiting until the excel is written and the E-Mail cannot find the attachment.
How can I make my Lambda function wait until the excel is written to disk?
node.js asynchronous
node.js asynchronous
edited Nov 16 '18 at 1:30
jhpratt
3,184102433
asked Nov 16 '18 at 0:58
AlexAlex
5610
edited Nov 16 '18 at 1:30
jhpratt
3,184102433
asked Nov 16 '18 at 0:58
AlexAlex
5610
edited Nov 16 '18 at 1:30
jhpratt
3,184102433
edited Nov 16 '18 at 1:30
jhpratt
3,184102433
edited Nov 16 '18 at 1:30
jhpratt
3,184102433
3,184102433
asked Nov 16 '18 at 0:58
AlexAlex
5610
asked Nov 16 '18 at 0:58
AlexAlex
5610
asked Nov 16 '18 at 0:58
AlexAlex
5610
5610
You probably want to look at How do I convert an existing callback API to promises?
– Felix Kling
Nov 16 '18 at 1:11
add a comment |
You probably want to look at How do I convert an existing callback API to promises?
– Felix Kling
Nov 16 '18 at 1:11
You probably want to look at How do I convert an existing callback API to promises?
– Felix Kling
Nov 16 '18 at 1:11
You probably want to look at How do I convert an existing callback API to promises?
– Felix Kling
Nov 16 '18 at 1:11
add a comment |
2 Answers
2
active
oldest
votes
await only works with functions that return a promise that resolves when the underlying asynchronous operation is complete. Since you are passing a completion-style callback to the function, it likely does not return such a promise.
If the library you are using does not directly support promises, then you can promisify the function yourself.
const util = require('util');
workbook.writeP = util.promisify(workbook.write);
async function someFunc()
try
let result = await workbook.writeP(path);
console.log(result);
// do something here that runs after the .write operation is done
catch(e)
console.log(e);
answered Nov 16 '18 at 1:07
jfriend00jfriend00
439k55576621
add a comment |
I suggest putting the emailing code in the callback, in the else block.
answered Nov 16 '18 at 1:21
Sergio FloresSergio Flores
1126
The better option would be to actually use theasync/awaitkeywords that are part of the language.
– jhpratt
Nov 16 '18 at 1:25
I tried that, but then the Lambda function finishes before the E-Mail is sent
– Alex
Nov 16 '18 at 1:30
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
await only works with functions that return a promise that resolves when the underlying asynchronous operation is complete. Since you are passing a completion-style callback to the function, it likely does not return such a promise.
If the library you are using does not directly support promises, then you can promisify the function yourself.
const util = require('util');
workbook.writeP = util.promisify(workbook.write);
async function someFunc()
try
let result = await workbook.writeP(path);
console.log(result);
// do something here that runs after the .write operation is done
catch(e)
console.log(e);
answered Nov 16 '18 at 1:07
jfriend00jfriend00
439k55576621
add a comment |
await only works with functions that return a promise that resolves when the underlying asynchronous operation is complete. Since you are passing a completion-style callback to the function, it likely does not return such a promise.
If the library you are using does not directly support promises, then you can promisify the function yourself.
const util = require('util');
workbook.writeP = util.promisify(workbook.write);
async function someFunc()
try
let result = await workbook.writeP(path);
console.log(result);
// do something here that runs after the .write operation is done
catch(e)
console.log(e);
answered Nov 16 '18 at 1:07
jfriend00jfriend00
439k55576621
add a comment |
await only works with functions that return a promise that resolves when the underlying asynchronous operation is complete. Since you are passing a completion-style callback to the function, it likely does not return such a promise.
If the library you are using does not directly support promises, then you can promisify the function yourself.
const util = require('util');
workbook.writeP = util.promisify(workbook.write);
async function someFunc()
try
let result = await workbook.writeP(path);
console.log(result);
// do something here that runs after the .write operation is done
catch(e)
console.log(e);
answered Nov 16 '18 at 1:07
jfriend00jfriend00
439k55576621
await only works with functions that return a promise that resolves when the underlying asynchronous operation is complete. Since you are passing a completion-style callback to the function, it likely does not return such a promise.
If the library you are using does not directly support promises, then you can promisify the function yourself.
const util = require('util');
workbook.writeP = util.promisify(workbook.write);
async function someFunc()
try
let result = await workbook.writeP(path);
console.log(result);
// do something here that runs after the .write operation is done
catch(e)
console.log(e);
answered Nov 16 '18 at 1:07
jfriend00jfriend00
439k55576621
edited Nov 16 '18 at 1:12
answered Nov 16 '18 at 1:07
jfriend00jfriend00
439k55576621
answered Nov 16 '18 at 1:07
jfriend00jfriend00
439k55576621
answered Nov 16 '18 at 1:07
jfriend00jfriend00
439k55576621
439k55576621
add a comment |
add a comment |
I suggest putting the emailing code in the callback, in the else block.
answered Nov 16 '18 at 1:21
Sergio FloresSergio Flores
1126
The better option would be to actually use theasync/awaitkeywords that are part of the language.
– jhpratt
Nov 16 '18 at 1:25
I tried that, but then the Lambda function finishes before the E-Mail is sent
– Alex
Nov 16 '18 at 1:30
add a comment |
I suggest putting the emailing code in the callback, in the else block.
answered Nov 16 '18 at 1:21
Sergio FloresSergio Flores
1126
The better option would be to actually use theasync/awaitkeywords that are part of the language.
– jhpratt
Nov 16 '18 at 1:25
I tried that, but then the Lambda function finishes before the E-Mail is sent
– Alex
Nov 16 '18 at 1:30
add a comment |
I suggest putting the emailing code in the callback, in the else block.
answered Nov 16 '18 at 1:21
Sergio FloresSergio Flores
1126
I suggest putting the emailing code in the callback, in the else block.
answered Nov 16 '18 at 1:21
Sergio FloresSergio Flores
1126
answered Nov 16 '18 at 1:21
Sergio FloresSergio Flores
1126
answered Nov 16 '18 at 1:21
Sergio FloresSergio Flores
1126
answered Nov 16 '18 at 1:21
Sergio FloresSergio Flores
1126
1126
The better option would be to actually use theasync/awaitkeywords that are part of the language.
– jhpratt
Nov 16 '18 at 1:25
I tried that, but then the Lambda function finishes before the E-Mail is sent
– Alex
Nov 16 '18 at 1:30
add a comment |
The better option would be to actually use theasync/awaitkeywords that are part of the language.
– jhpratt
Nov 16 '18 at 1:25
I tried that, but then the Lambda function finishes before the E-Mail is sent
– Alex
Nov 16 '18 at 1:30
The better option would be to actually use the
async/await keywords that are part of the language.– jhpratt
Nov 16 '18 at 1:25
The better option would be to actually use the
async/await keywords that are part of the language.– jhpratt
Nov 16 '18 at 1:25
I tried that, but then the Lambda function finishes before the E-Mail is sent
– Alex
Nov 16 '18 at 1:30
I tried that, but then the Lambda function finishes before the E-Mail is sent
– Alex
Nov 16 '18 at 1:30
add a comment |
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You probably want to look at How do I convert an existing callback API to promises?
– Felix Kling
Nov 16 '18 at 1:11