cmd/geth: support string (non-hex) keys in db get/put/delete

[zhiburt]

Hi,

This flag suppose to bring a little more convenience, when observing internal state,
via constant keys like SnapshotSyncStatus, SnapshotRecovery etc.

Now it's necessary to convert these strings to hex and to add a prefix 0x which might be inconvenient.
And not intuitive at a first glance.

[holiman]

Great, I've been annoyed by this same thing myself!

[holiman]

A couple of things:

• Simiar thing should be applied for db put and db delete aswell.
  • However, for db put, it's a bit more problematic: there's both a key and a value. And most likely, one wants the key in ascii but the value in hex (because most data is not ascii). So the logic should only apply for the key.
• A simpler (more hacky) variant would be to always try and parse the key as hex first, and, failing that, fall back to ascii interpretation. Then we wouldn't need a flag. Then it wouldn't be possible to use a key which literally is the string 0x123, but I don't know if that matters. I'm leaning towards doing that instead, that makes the UX a bit nicer.
• Also, I don't know why you call it utf-8. It's simply the raw bytes of the input string. Whether it's UTF-8 or ascii or something else entirely, I guess that's up to the shell / OS. All our string-based keys are representable in ascii.

[zhiburt]

Simiar thing should be applied for db put and db delete aswell.

However, for db put, it's a bit more problematic: there's both a key and a value. And most likely, one wants the key in ascii but the value in hex (because most data is not ascii). So the logic should only apply for the key.

Agreed

A simpler (more hacky) variant would be to always try and parse the key as hex first, and, failing that, fall back to ascii interpretation. Then we wouldn't need a flag. Then it wouldn't be possible to use a key which literally is the string 0x123, but I don't know if that matters. I'm leaning towards doing that instead, that makes the UX a bit nicer.

I guess it doesn't because it in such case user could provide such a key encoded in hex right after 0x.
So the key would be 0x3078313233

Also, I don't know why you call it utf-8. It's simply the raw bytes of the input string. Whether it's UTF-8 or ascii or something else entirely, I guess that's up to the shell / OS. All our string-based keys are representable in ascii.

You are right.
I was calling it utf8 because in go we get it as utf8 no matter which encoding was on the input.
*I guess

[zhiburt]

Must be fixed according to your comments @holiman

[holiman]

I pushed a fix, it works now:

[user@work go-ethereum]$ geth db get DatabaseVersion
INFO [10-18|10:33:03.906] Maximum peer count                       ETH=50 LES=0 total=50
INFO [10-18|10:33:03.906] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [10-18|10:33:03.907] Set global gas cap                       cap=50,000,000
INFO [10-18|10:33:03.907] Allocated cache and file handles         database=/home/user/.ethereum/geth/chaindata cache=512.00MiB handles=262,144 readonly=true
INFO [10-18|10:33:03.952] Opened ancient database                  database=/home/user/.ethereum/geth/chaindata/ancient readonly=true
key 0x446174616261736556657273696f6e: 0x08

[user@work go-ethereum]$ geth db put DatabaseVersion 0x09
INFO [10-18|10:33:09.782] Maximum peer count                       ETH=50 LES=0 total=50
INFO [10-18|10:33:09.782] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [10-18|10:33:09.784] Set global gas cap                       cap=50,000,000
INFO [10-18|10:33:09.784] Allocated cache and file handles         database=/home/user/.ethereum/geth/chaindata cache=512.00MiB handles=262,144
INFO [10-18|10:33:09.864] Opened ancient database                  database=/home/user/.ethereum/geth/chaindata/ancient readonly=false
Previous value: 0x08
INFO [10-18|10:33:09.868] Freezer shutting down 

[user@work go-ethereum]$ geth db put DatabaseVersion 0x08
INFO [10-18|10:33:13.268] Maximum peer count                       ETH=50 LES=0 total=50
INFO [10-18|10:33:13.268] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [10-18|10:33:13.269] Set global gas cap                       cap=50,000,000
INFO [10-18|10:33:13.269] Allocated cache and file handles         database=/home/user/.ethereum/geth/chaindata cache=512.00MiB handles=262,144
INFO [10-18|10:33:13.322] Opened ancient database                  database=/home/user/.ethereum/geth/chaindata/ancient readonly=false
Previous value: 0x09
INFO [10-18|10:33:13.324] Freezer shutting down 

[user@work go-ethereum]$ geth db delete DatabaseVersion
INFO [10-18|10:34:08.064] Maximum peer count                       ETH=50 LES=0 total=50
INFO [10-18|10:34:08.064] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [10-18|10:34:08.065] Set global gas cap                       cap=50,000,000
INFO [10-18|10:34:08.065] Allocated cache and file handles         database=/home/user/.ethereum/geth/chaindata cache=512.00MiB handles=262,144
INFO [10-18|10:34:08.093] Opened ancient database                  database=/home/user/.ethereum/geth/chaindata/ancient readonly=false
Previous value: 0x08
INFO [10-18|10:34:08.093] Freezer shutting down 

[user@work go-ethereum]$ geth db get DatabaseVersion
INFO [10-18|10:34:12.224] Maximum peer count                       ETH=50 LES=0 total=50
INFO [10-18|10:34:12.224] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [10-18|10:34:12.224] Set global gas cap                       cap=50,000,000
INFO [10-18|10:34:12.224] Allocated cache and file handles         database=/home/user/.ethereum/geth/chaindata cache=512.00MiB handles=262,144 readonly=true
INFO [10-18|10:34:12.236] Opened ancient database                  database=/home/user/.ethereum/geth/chaindata/ancient readonly=true
INFO [10-18|10:34:12.237] Get operation failed                     key=0x0x446174616261736556657273696f6e error="leveldb: not found"
leveldb: not found

[user@work go-ethereum]$ geth db put DatabaseVersion 0x08
INFO [10-18|10:34:15.462] Maximum peer count                       ETH=50 LES=0 total=50
INFO [10-18|10:34:15.462] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [10-18|10:34:15.463] Set global gas cap                       cap=50,000,000
INFO [10-18|10:34:15.463] Allocated cache and file handles         database=/home/user/.ethereum/geth/chaindata cache=512.00MiB handles=262,144
INFO [10-18|10:34:15.492] Opened ancient database                  database=/home/user/.ethereum/geth/chaindata/ancient readonly=false
INFO [10-18|10:34:15.493] Freezer shutting down 

[zhiburt]

I pushed a fix, it works now:

thanks, haven't spotted that 😞