Invalid memory address / bad endpoint '' ?

[na6vj]

Ran into invalid memory address or nil pointer dereference on version 0.62 :

yugabyte@cud1c-003828:(/home/yugabyte/scripts/promdump)# ./promdump --universe_name=CAS-UAT-PVS_Primary --start_time $PROMDUMP_STARTTIME --end_time $PROMDUMP_ENDTIME --yba_api_token=$API_TOKEN --yba_api_hostname=cud1c-003828.csdev.corp
2024/10/08 12:43:04 promdump version v0.6.2 from commit c9bb2d10a5cbced2387bf236f10870b9dfb8f559 built 2024-10-03T20:57:05+00:00
2024/10/08 12:43:04 main: using the following flags: --end_time=2024-10-07T23:20:00Z --start_time=2024-10-07T23:00:00Z --universe_name=CAS-UAT-PVS_Primary --yba_api_hostname=cud1c-003828.csdev.corp --yba_api_token=****
2024/10/08 12:43:04 main: logging to file 'promdump.log'
2024/10/08 12:43:04 The --yba_api_token flag is required when using the YBA API. See the YBA API documentation at: https://api-docs.yugabyte.com/
yugabyte@cud1c-003828:(/home/yugabyte/scripts/promdump)# ./promdump --universe_name=CAS-UAT-PVS-Primary --start_time $PROMDUMP_STARTTIME --end_time $PROMDUMP_ENDTIME --yba_api_token=$API_TOKEN --yba_api_hostname=cud1c-003828.csdev.corp
2024/10/08 12:43:27 promdump version v0.6.2 from commit c9bb2d10a5cbced2387bf236f10870b9dfb8f559 built 2024-10-03T20:57:05+00:00
2024/10/08 12:43:27 main: using the following flags: --end_time=2024-10-07T23:20:00Z --start_time=2024-10-07T23:00:00Z --universe_name=CAS-UAT-PVS-Primary --yba_api_hostname=cud1c-003828.csdev.corp --yba_api_token=****
2024/10/08 12:43:27 main: logging to file 'promdump.log'
2024/10/08 12:43:27 The --yba_api_token flag is required when using the YBA API. See the YBA API documentation at: https://api-docs.yugabyte.com/
yugabyte@cud1c-003828:(/home/yugabyte/scripts/promdump)# source /home/yugabyte/.yba_dev.tc
-bash: /home/yugabyte/.yba_dev.tc: No such file or directory
yugabyte@cud1c-003828:(/home/yugabyte/scripts/promdump)# source /home/yugabyte/.yba_dev.rc
yugabyte@cud1c-003828:(/home/yugabyte/scripts/promdump)# ./promdump --universe_name=CAS-UAT-PVS-Primary --start_time $PROMDUMP_STARTTIME --end_time $PROMDUMP_ENDTIME --yba_api_token=$API_TOKEN --yba_api_hostname=cud1c-003828.csdev.corp
2024/10/08 12:43:48 promdump version v0.6.2 from commit c9bb2d10a5cbced2387bf236f10870b9dfb8f559 built 2024-10-03T20:57:05+00:00
2024/10/08 12:43:48 main: using the following flags: --end_time=2024-10-07T23:20:00Z --start_time=2024-10-07T23:00:00Z --universe_name=CAS-UAT-PVS-Primary --yba_api_hostname=cud1c-003828.csdev.corp --yba_api_token=****
2024/10/08 12:43:48 main: logging to file 'promdump.log'
2024/10/08 12:43:48 main: Connecting to YBA API
2024/10/08 12:43:48 Using hostname 'cud1c-003828.csdev.corp' to connect to the YBA API
2024/10/08 12:43:48 Found customer UUID '311bddaf-f9c5-4c9a-a510-36562a800c07'
2024/10/08 12:43:48 Looking up Universe with name 'CAS-UAT-PVS-Primary' using the YBA API
2024/10/08 12:43:48 Found Universe 'CAS-UAT-PVS-Primary'
2024/10/08 12:43:48 Found node prefix 'yb-dev-CAS-UAT-PVS-Primary' for Universe 'CAS-UAT-PVS-Primary'
2024/10/08 12:43:48 main: Finished with YBA API
2024/10/08 12:43:48 main: not filtering by exported_instance
2024/10/08 12:43:48 main: collecting the following Yugabyte metrics: cql_export, master_export, node_export, platform, tserver_export, ysql_export
2024/10/08 12:43:48 main: skipping the following Yugabyte metrics: prometheus
2024/10/08 12:43:48 main: tar bundling enabled
2024/10/08 12:43:48 main: no --tar_filename specified; using filename 'promdump-yb-dev-CAS-UAT-PVS-Primary-20241008-124348.tar.gz'
2024/10/08 12:43:48 main: Beginning metric collection against Prometheus endpoint ''
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x6ebb8c]
 
goroutine 1 [running]:
main.main()
        /home/runner/work/prometheus-remote-backfill/prometheus-remote-backfill/promdump/promdump.go:1256 +0x1b4c

I noticed this may be due to a bad endpoint:
Beginning metric collection against Prometheus endpoint ''

We got a successful promdump after adding --url https:/...:9090

This ticket requests a better error message when the URL is missing.
Also, it seems redundant to specify --yba_api_hostname and --url .. you should be able to derive one from the other.

[ionthegeek]

@na6vj you probably meant to create this in https://github.com/yugabyte/prometheus-remote-backfill. I have a PR open to fix this crash in the Yugabyte fork.