Better error message for server connection errors

[seisman]

Sometimes, we may have intermittent network issues and fail to download some files. GMT reports errors likes:

movie [ERROR]: Libcurl Error: Couldn't connect to server
movie [ERROR]: You can turn remote file download off by setting GMT_DATA_SERVER_LIMIT = 0.

Is it possible to provide more information? For example.

• Couldn't connect to server http://oceania.generic-mapping-tools.org/
• Couldn't download file http://oceania.generic-mapping-tools.org/gmt_hash_servers.txt

[PaulWessel]

OK, will see what information is available when it fails. But for certain we know what it is trying to download when it fails so we can add more information. I experience the same thing from time to time.

[MarkWieczorek]

I get the following error in pygmt from time to time when plotting my own data. Why would gmt be trying to download these files at all? At a very minimum, this should return a warning as opposed to an error.

grdimage [ERROR]: Unable to download file https://oceania.generic-mapping-tools.org/gmt_hash_server.txt
grdimage [ERROR]: Libcurl Error: Timeout was reached
grdimage [ERROR]: GMT data server may be down - delay checking hash file for 24 hours
grdimage [ERROR]: You can turn remote file download off by setting GMT_DATA_SERVER_LIMIT = 0.
grdimage [ERROR]: Unable to obtain remote file @GMTAPI@-000000
grdimage [ERROR]: File GMTAPI@-000000 not found
[Session pygmt-session (4)]: Error returned from GMT API: GMT_FILE_NOT_FOUND (16)

[seisman]

I think GMT only tries to download the hash table (gmt_hash_server.txt) if a remote file (file with a leading "@") is required.

I see two possible issues here:

1. It seems GMT takes @GMTAPI@-000000 as a remote file.
2. As @MarkWieczorek suggested, failing to download gmt_hash_server.txt should be a warning instead of an error.

[PaulWessel]

We have explicit checks to not download @GMTAPI@-###### files and I have not seen that before. COuld you tell me the circumstance in which it happened. I know you use pygmt.

[MarkWieczorek]

The circumstance is very banal: I have a grid stored as a local xarray, and I am using grdimage to plot it. Here is an example if you want to check out a different problem! https://github.com/GenericMappingTools/pygmt/issues/375

[seisman]

I tried @MarkWieczorek's script in GenericMappingTools/pygmt#375. The first few lines of debug messages are:

grdimage [DEBUG]: Map distance calculation will be using great circle approximation with authalic auxiliary latitudes and authalic (R_2) radius = 6371007.1809 m, in meter.
grdimage [DEBUG]: Map distance calculation will be using great circle approximation with authalic auxiliary latitudes and authalic (R_2) radius = 6371007.1809 m, in meter.
grdimage [DEBUG]: Look for file @GMTAPI@-000000 in /Users/seisman/.gmt
grdimage [DEBUG]: Look for file @GMTAPI@-000000 in /Users/seisman/.gmt/cache
grdimage [DEBUG]: Look for file @GMTAPI@-000000 in /Users/seisman/.gmt/server
grdimage [DEBUG]: Look for file @GMTAPI@-000000 in /Users/seisman/.gmt/server/srtm1
grdimage [DEBUG]: Look for file @GMTAPI@-000000 in /Users/seisman/.gmt/server/srtm3
grdimage [INFORMATION]: Read header from file @GMTAPI@-000000
grdimage [DEBUG]: Local file /Users/seisman/.gmt/server/gmt_hash_server.txt found
grdimage [DEBUG]: File /Users/seisman/.gmt/server/gmt_hash_server.txt less than 24 hours old, refresh is premature.
grdimage [DEBUG]: api_begin_io: Input resource access is now enabled [container]

[seisman]

@PaulWessel I'm reopening it since there are still some unsolved issues here.

[PaulWessel]

OK, fine.

[stale[bot]]

This issue has been automatically marked as stale because it has not had activity in the last 90 days. It will be closed if no further activity occurs within 7 days. Thank you for your contributions.

[joa-quim]

Can we close this?