Speed up Exchange backup by parallelizing url fetch

[meain]

Description

From rough numbers we can speedup an account with ~3000 emails, ~1000 contacts and ~1000 events from ~18m to <3m.

Type of change

• 🌻 Feature
• 🐛 Bugfix
• 🗺️ Documentation
• 🤖 Test
• 💻 CI/Deployment
• 🐹 Trivial/Minor

Issue(s)

• GC: Add routines for large operations #362
• Speed up initial OneDrive/Exchange backup #1595
• Parallelize OneDrive queries to get URL #1607

Test Plan

• 💪 Manual
• ⚡ Unit test
• 💚 E2E

[ryanfkeepers]

All comments from the onedrive version of this PR also apply.

[ryanfkeepers]

nit: bit of a weird comparison. I'd rather the code make more sense, even if the const seems off by one.

Suggested change

	if i != numberOfRetries-1 {
	if i >= numberOfRetries {

[meain]

I don't think i >= numberOfRetries will work. I think I'll probably change the code to the following to make it more explicit though:

for i := 1; i <= numberOfRetries; i++ {
    ...
    if i < numberOfRetries {
        time.Sleep(time.Duration(3*(i+1)) * time.Second)
    }
}

[ryanfkeepers]

Hah, good catch. My brain was backwards. Though, for simplicity, I'd probably go with something like:

for i := 0; i < numberOfRetries; i++ {
  response, err = query(...)
  if err == nil {
    break
  }
  time.Sleep(duration)
}

The additional conditional and fiddling with the retry count is just code noise.

[meain]

The reason for the conditional was so that it would not sleep even with an error in the last run. If we skip that, it sleeps at the end of n-1th run before exiting out of the loop.

[dadams39]

Is there a reason to switch from 32 to 64?

[meain]

I had to switch it to either int32 or int64 as I needed to do an atomic increment. And since int will be int64 on most platforms we will be deploying, I thought I would go with int64.

[dadams39]

Could this be added to the defer on Line 135?

[meain]

I thought it would be better to couple it with the make as the defer above is just for the progressbar.

[dadams39]

These can be grouped.

Additionally, a comment would be helpful.

[meain]

Any specific reason for grouping them? Let me add comments to it though.

[meain]

I've added comments to the channel creation.

[dadams39]

There are several different code declarations. Could it be simplified into the top of the function?

[meain]

These are the only declarations in the func called as a goroutine.

[aviator-app]

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[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
2 Code Smells

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