Add Google Cloud Storage S3 compatible table function

[jkaflik]

Changelog category (leave one):

• Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Add Google Cloud Storage S3 compatible table function gcs. Like the oss and cosn functions, it is just an alias over the s3 table function, and it does not bring any new features.

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

Information about CI checks: https://clickhouse.com/docs/en/development/continuous-integration/

[nikitamikhaylov]

@jkaflik @alexey-milovidov There is a build error, rebasing to a recent master won't help in any way.

Apr 17 06:34:01 In file included from /build/src/TableFunctions/TableFunctionS3Cluster.cpp:14:
Apr 17 06:34:01 /build/src/TableFunctions/TableFunctionS3.h:96:33: error: unknown class name 'TableFunctionS3'; did you mean 'DB::TableFunctionS3'?
Apr 17 06:34:01 class TableFunctionGCS : public TableFunctionS3
Apr 17 06:34:01                                 ^~~~~~~~~~~~~~~
Apr 17 06:34:01                                 DB::TableFunctionS3
Apr 17 06:34:01 /build/src/TableFunctions/TableFunctionS3.h:18:7: note: 'DB::TableFunctionS3' declared here
Apr 17 06:34:01 class TableFunctionS3 : public ITableFunction
Apr 17 06:34:01       ^
Apr 17 06:34:01 /build/src/TableFunctions/TableFunctionS3.h:116:1: error: extraneous closing brace ('}')
Apr 17 06:34:01 }
Apr 17 06:34:01 ^
Apr 17 06:34:01 2 errors generated.
Apr 17 06:34:01 [11311/11344] Building CXX object programs/local/CMakeFiles/clickhouse-local-lib.dir/LocalServer.cpp.o
Apr 17 06:34:01 [11312/11344] Building CXX object programs/copier/CMakeFiles/clickhouse-copier-lib.dir/TaskCluster.cpp.o
Apr 17 06:34:02 [11313/11344] Building CXX object src/TableFunctions/CMakeFiles/clickhouse_table_functions.dir/TableFunctionS3.cpp.o

[jkaflik]

@nikitamikhaylov thanks. I will have a look. (never been on my priority list)

[alexey-milovidov]

You've put it outside of the namespace.

[alexey-milovidov]

@jkaflik I've edited the changelog to more clearly describe the innovation.

[alexey-milovidov]

@jkaflik it is not documented in the code base.

[robot-clickhouse]

This is an automated comment for commit 8a6084a with description of existing statuses. It's updated for the latest CI running
The full report is available here
The overall status of the commit is 🔴 failure

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[robot-clickhouse]

This is an automated comment for commit 0672d75 with description of existing statuses. It's updated for the latest CI running
The full report is available here
The overall status of the commit is 🟡 pending

Check name	Description	Status
CI running	A meta-check that indicates the running CI. Normally, it's in success or pending state. The failed status indicates some problems with the PR	🟡 pending
Mergeable Check	Checks if all other necessary checks are successful	🟢 success

[jkaflik]

@alexey-milovidov I added inline code documentation. I did it for S3, also. Not familiar with COS and OSS. It can be added in the future.