globalDeploymentID was being read while it was being set.
Fixes race:
```
WARNING: DATA RACE
Write at 0x0000079605a0 by main goroutine:
github.com/minio/minio/cmd.connectLoadInitFormats()
github.com/minio/minio/cmd/prepare-storage.go:269 +0x14f0
github.com/minio/minio/cmd.waitForFormatErasure()
github.com/minio/minio/cmd/prepare-storage.go:294 +0x21d
...
Previous read at 0x0000079605a0 by goroutine 105:
github.com/minio/minio/cmd.newContext()
github.com/minio/minio/cmd/utils.go:817 +0x31e
github.com/minio/minio/cmd.adminMiddleware.func1()
github.com/minio/minio/cmd/admin-router.go:110 +0x96
net/http.HandlerFunc.ServeHTTP()
net/http/server.go:2136 +0x47
github.com/minio/minio/cmd.setBucketForwardingMiddleware.func1()
github.com/minio/minio/cmd/generic-handlers.go:460 +0xb1a
net/http.HandlerFunc.ServeHTTP()
net/http/server.go:2136 +0x47
...
```
* Add periodic callhome functionality
Periodically (every 24hrs by default), fetch callhome information and
upload it to SUBNET.
New config keys under the `callhome` subsystem:
enable - Set to `on` for enabling callhome. Default `off`
frequency - Interval between callhome cycles. Default `24h`
* Improvements based on review comments
- Update `enableCallhome` safely
- Rename pctx to ctx
- Block during execution of callhome
- Store parsed proxy URL in global subnet config
- Store callhome URL(s) in constants
- Use existing global transport
- Pass auth token to subnetPostReq
- Use `config.EnableOn` instead of `"on"`
* Use atomic package instead of lock
* Use uber atomic package
* Use `Cancel` instead of `cancel`
Co-authored-by: Harshavardhana <harsha@minio.io>
Co-authored-by: Harshavardhana <harsha@minio.io>
Co-authored-by: Aditya Manthramurthy <donatello@users.noreply.github.com>
Klaus Post
Aditya Manthramurthy
Shubhendu
Anis Elleuch
Shireesh Anjal
Harshavardhana