Issue: Connection to Data Warehouse SQL Endpoint in Microsoft Fabric Fails with "Read: EOF" Error #230
Comments
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I think it's due to #226 |
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@jaume-pladevall-itk could you try building with the latest commit in main (#228 ) and see if it fixes your issue? I'd love a 3rd party validation before I push a 1.8 tag. |
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@shueybubbles Now with the latest commit in main (#228) it works again. Thank you very much! |
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Seems it's still happening when using |
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@flarco did your sling dev build upgrade go-mssqldb to v1.8? |
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Yes, see here: https://github.com/slingdata-io/sling-cli/compare/v1.3.4 (commit |
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FWIW if I use the latest go-sqlcmd based on go-mssqldb I can access a Fabric DW that's in our "daily" environment. I can use both |
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Here is the output with and my ~/.sling/.env file FABRIC_WH2: # DOESNT WORK !!!!
type: sqlserver # also tried azure-synapse-analytics
host: REDACTED.datawarehouse.fabric.microsoft.com
user: REDACTED
password: "REDACTED"
database: warehouse2
schema: src_customer
fedauth: ActiveDirectoryServicePrincipal
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@johnoscott is it possible you can attach a logger to the driver with the log level set to 0x8fff? At minimum you'd be able to verify the driver is correctly adding a connection id and activity id to the prelogin packet, and you could give those guids to Microsoft support if you need them to help identify why the connection is being closed. One way you could get this same information is use the newest release from github.com/microsoft/go-sqlcmd and pass it on the command line: |
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I am using macOS and I am expecting that authenticating with method ActiveDirectoryServicePrincipal will work (even though interactive authentication (which i am not using) is known not to work ) So I tried Windows 11 |
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OK that macOS version was using sqlcmd from a package of mssql-tools, which explains the different version number. When i install sqlcmd directly i get ... |
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@johnoscott sorry I should have been more explicit - go-sqlcmd v1.8.2 still hasn't been marked as "latest" but it's the version that has the activity id and connection id fix. |
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OK it appears to be working with upcoming v1.8.2 |
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@shueybubbles when can we expect 1.8.2 to be marked as latest ? |
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it was marked latest already |
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@shueybubbles thanks, I see the most recent release shows 
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go-sqlcmd v1.8.2 uses go-mssqldb 1.8.0. Both are marked |
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@shueybubbles This is the URL that sling is using to connect:
Do you mind looking at it and sharing if anything is wrong with it? Sling calls a |
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@flarco I think the string is ok. Can you attach a logger to the driver with level 33279 ? It should emit a trace like this: It's possible that something with your environment somehow bypasses that connection id generation. |
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@shueybubbles is there an environment variable that I can use to set the log level? |
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I think you need to use |
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@shueybubbles thank you, using @johnoscott can you download the latest dev build and post the output with |
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here you go @flarco. The only way i could get the |
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@shueybubbles does that log help? |
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I think you can use those activity and connection IDs to open a support ticket with the Fabric DW team to find out why the service closed the second connection. I don't know much about their service other than what they indicated in #228 |
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@shueybubbles i am not sure a support ticket will help. I used the same credentials to make a successful connection with both a python app and sqlcmd. What else do you think could cause the connection to fail ? |
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it's not a credential problem; it's likely some subtle TDS protocol issue where Fabric DW has decided the driver has violated the protocol. The source of this issue was go-mssqldb was not adding connection and activity guids to the prelogin packet, leading the Fabric DW rejecting the connection. Maybe there's some other bit missing from a TDS packet which they are rejecting. We don't know what the real problem is without that team's input. The connection and activity guids in prelogin are kept in their telemetry, so their support team should be able to find the connection attempt and give a reason for the rejection. |
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@johnoscott I added logic to emulate the authentication conn string the same way sqlcmd auths here: https://github.com/microsoft/go-sqlcmd/blob/main/pkg/sqlcmd/sqlcmd.go#L278 Can you give the latest dev build a try to see if it makes a difference? |
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@flarco I tried again with latest dev version (had same 1.3.6 version as last one but with later build date). Connection is still failing. I added a Also, what is the For comparison, here is a sqlcmd debug output using the same credentials. |
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@johnoscott Oh I think the issue is probably the driver name.
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@flarco does this help ? |
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@johnoscott I was just looking at this. Pushed a change to use |
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Alright ! Its working now 👍 Here is the debug output |
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@johnoscott Great! |
We implemented a connection to a Data Warehouse SQL endpoint in Microsoft Fabric, but it suddenly stopped working and began returning the error message “Read: EOF” without any changes to our code.
We use the following code to connect to the database:
The code above returns the error "Ping failed: Read: EOF" where
urlhas the following format:"long_mix_of_numbers_and_chars.datawarehouse.fabric.microsoft.com"anddatabaseis the name of the table we want to access inside the Data Warehouse.We are using Go 1.22.0 and go-mssqldb version v1.7.2.
Upon debugging the go-mssqldb library, it appears that a first connection is established, as it enters the
loginAckStructcase (line 1366 of the file tds.go). Then, it enters the conditionsess.routedServer != ""(line 1393 of the file tds.go) and initiates another connection, which is the one that returns the "Read: EOF" error.We also tried connecting to the SQL endpoint using SQL Server Management Studio (SSMS) and directly accessing the Data Warehouse from Microsoft Fabric. Both methods work successfully.
Has anyone else experienced the same issue? If so, could you share your insights or solutions? Additionally, if anyone has any clues as to why this might be happening or how to resolve it, your help would be greatly appreciated. Thank you!
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