Unstable test: TestHotReloadUIConfigTempFile

[yurishkuro]

I've seen this one failing sporadically:

=== RUN   TestHotReloadUIConfigTempFile
    static_handler_test.go:279: 
        	Error Trace:	static_handler_test.go:279
        	Error:      	"" does not contain "About a new Jaeger"
        	Test:       	TestHotReloadUIConfigTempFile
        	Messages:   	[{Entry:{Level:info Time:2022-05-25 20:44:07.707232055 +0000 UTC m=+2.677106569 LoggerName: Message:watching Caller:undefined Stack:} Context:[{Key:file Type:15 Integer:0 String:/tmp/ui-config-hotreload-225331457/486536771.json Interface:<nil>}]} {Entry:{Level:info Time:2022-05-25 20:44:07.707258755 +0000 UTC m=+2.677133369 LoggerName: Message:watching Caller:undefined Stack:} Context:[{Key:dir Type:15 Integer:0 String:/tmp/ui-config-hotreload-225331457 Interface:<nil>}]} {Entry:{Level:info Time:2022-05-25 20:44:07.708553363 +0000 UTC m=+2.678427877 LoggerName: Message:reloading UI config Caller:undefined Stack:} Context:[{Key:filename Type:15 Integer:0 String:/tmp/ui-config-hotreload-225331457/486536771.json Interface:<nil>}]} {Entry:{Level:error Time:2022-05-25 20:44:07.708720364 +0000 UTC m=+2.678594978 LoggerName: Message:error while reloading the UI config Caller:undefined Stack:} Context:[{Key:error Type:26 Integer:0 String: Interface:cannot parse UI config file /tmp/ui-config-hotreload-225331457/486536771.json: unexpected end of JSON input}]} {Entry:{Level:info Time:2022-05-25 20:44:07.708730865 +0000 UTC m=+2.678605379 LoggerName: Message:reloaded UI config Caller:undefined Stack:} Context:[{Key:filename Type:15 Integer:0 String:/tmp/ui-config-hotreload-225331457/486536771.json Interface:<nil>}]} {Entry:{Level:info Time:2022-05-25 20:44:07.708748465 +0000 UTC m=+2.678623079 LoggerName: Message:reloading UI config Caller:undefined Stack:} Context:[{Key:filename Type:15 Integer:0 String:/tmp/ui-config-hotreload-225331457/486536771.json Interface:<nil>}]} {Entry:{Level:error Time:2022-05-25 20:44:07.708856265 +0000 UTC m=+2.678730879 LoggerName: Message:error while reloading the UI config Caller:undefined Stack:} Context:[{Key:error Type:26 Integer:0 String: Interface:cannot parse UI config file /tmp/ui-config-hotreload-225331457/486536771.json: unexpected end of JSON input}]} {Entry:{Level:info Time:2022-05-25 20:44:07.708863765 +0000 UTC m=+2.678738379 LoggerName: Message:reloaded UI config Caller:undefined Stack:} Context:[{Key:filename Type:15 Integer:0 String:/tmp/ui-config-hotreload-225331457/486536771.json Interface:<nil>}]}]
--- FAIL: TestHotReloadUIConfigTempFile (0.02s)

Likely some kind of race condition dependent on the timing of hot reload.

[Frapschen]

hi,I can help it.

[yurishkuro]

please do

[Frapschen]

as the code refer(static_handler.go line:238):

		if err := json.Unmarshal(bytesConfig, &c); err != nil {
			return nil, fmt.Errorf("cannot parse UI config file %v: %w", uiConfig, err)
		}

if there occur a error, the err must be not nil, while the log info show that the err is <nil>. how it can happen?

[yurishkuro]

The error in the logs is "cannot parse UI config file /tmp/ui-config-hotreload-225331457/486536771.json: unexpected end of JSON input"

[yurishkuro]

Are we overwriting the file content or replacing the file with mv command?

[Frapschen]

Are we overwriting the file content or replacing the file with mv command?
I just overwrite the file content.