Azure Function connect Azure PostgreSQL ETIMEDOUT, errno: -4039 - node.js

Question

I have an Azure (AZ) Function does two things:
validate submitted info involving 3rd party packages.
when ok call a postgreSQL function at AZ to fetch a small set of data
Testing with Postman, this AF localhost response time < 40 ms. Deployed to Cloud, change URL to AZ, same set of data, took 30 seconds got Status: 500 Internal Server Error.
Did a search, thought this SO might be the case, that I need to bump my subscription to the expensive one to avoid cold start.
But more investigation running part 1 and 2 individually and combined, found:
validation part alone runs perfect at AZ, response time < 40ms, just like local, suggests cold start/npm-installation is not an issue.
pg function call always long and status: 500 regardless it runs alone or succeeding part 1, no data returned.
Application Insight is enabled and added a Diagnostic settings with:
FunctionAppLogs and AllMetrics selected
Send to LogAnalytiscs workspace and Stream to an event hub selected
Following queries found no error/exceptions:
requests | order by timestamp desc |limit 100 // success is "true", time taken 30 seconds, status = 500
traces | order by timestamp desc | limit 30 // success is "true", time taken 30 seconds, status = 500
exceptions | limit 30 // no data returned
How complicated my pg call is? Standard connection, simple and short:
require('dotenv').config({ path: './environment/PostgreSql.env'});
const fs = require("fs");
const pgp = require('pg-promise')(); // () = taking default initOptions
require('dotenv').config({ path: './environment/PostgreSql.env'});
const fs = require("fs");
const pgp = require('pg-promise')(); // () = taking default initOptions
db = pgp(
{
user: process.env.PGuser,
host: process.env.PGhost,
database: process.env.PGdatabase,
password: process.env.PGpassword,
port: process.env.PGport,
ssl:
{
rejectUnauthorized: true,
ca: fs.readFileSync("./environment/DigiCertGlobalRootCA.crt.pem").toString(),
},
}
);
const pgTest = (nothing) =>
{
return new Promise((resolve, reject) =>
{
var sql = 'select * from schema.test()'; // test() does a select from a 2-row narrrow table.
db.any(sql)
.then
(
good => resolve(good),
bad => reject({status: 555, body: bad})
)
}
);
}
module.exports = { pgTest }
AF test1 is a standard httpTrigger anonymous access:
const x1 = require("package1");
...
const xx = require("packagex");
const pgdb = require("db");
module.exports = function(context)
{
try
{
pgdb.pgTest(1)
.then
(
good => {context.res={body: good}; context.done();},
bad => {context.res={body: bad}; context.done();}
)
.catch(err => {console.log(err)})
}
catch(e)
{ context.res={body: bad}; context.done(); }
}
Note:
AZ = Azure.
AZ pg doesn't require SSL.
pg connectivity method: public access (allowed IP addresses)
Postman tests on Local F5 run against the same AZ pg database, all same region.
pgAdmin and psql all running fast against the same.
AF-deploy is zip-file deployment, my understanding it is using the same configuration.
I'm new to Azure but based on my experience, if it's about credential then should come back right away.
Update 1, FunctionAppLogs | where TimeGenerated between ( datetime(2022-01-21 16:33:20) .. datetime(2022-01-21 16:35:46) )
Is it because my pg network access set to Public access?

Answer 1

My AZ pgDB is a flexible server, current Networking is Public access (allowed IP address), and I have added some Firewall rule w/ client IP address. My assumption is access is allowed within AZ, but it's not.
Solution 1, simply check this box: Allow public access from any Azure servcie within Azure to this server at the bottom of the Settings -> Networking.
Solution 2, find out all AF's outbound IP and add them into Firewall rule, under Settings -> Networking. Reason to add them all is Azure select an outbound IP randomly.