feat: Implement SHOW CREATE FLOW

[irenjj]

I hereby agree to the terms of the GreptimeDB CLA.

Refer to a related PR or issue link (optional)

close: #3939

What's changed and what's your intention?

Implement SHOW CREATE FLOW

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR requires documentation updates.

[codecov]

Codecov Report

Attention: Patch coverage is 41.80791% with 103 lines in your changes missing coverage. Please review.

Project coverage is 85.11%. Comparing base (03cacf9) to head (f848d71).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4040      +/-   ##
==========================================
- Coverage   85.48%   85.11%   -0.38%     
==========================================
  Files         993      994       +1     
  Lines      173751   173991     +240     
==========================================
- Hits       148539   148094     -445     
- Misses      25212    25897     +685     

[WenyXu]

Would you like to add some sqlness tests for SHOW FLOW?
BTW, It seems we need to add sqlness tests for creating flow and dropping flow cc @discord9 @waynexia

[irenjj]

Would you like to add some sqlness tests for SHOW FLOW? BTW, It seems we need to add sqlness tests for creating flow and dropping flow cc @discord9 @waynexia

Sure, i'll add tests after some review feedback, because the output format of SHOW CREATE FLOW might change.

[waynexia]

Please add some sqlness tests following https://github.com/GreptimeTeam/greptimedb/blob/main/tests/README.md

[irenjj]

Please add some sqlness tests following https://github.com/GreptimeTeam/greptimedb/blob/main/tests/README.md

It seems that the create flow statement randomly fails.

[discord9]

Sorry but currently flow only implement for standalone mode, could you move the testcase out of common folder for now? I will put it back when we have distributed support for flow service?

Please add some sqlness tests following https://github.com/GreptimeTeam/greptimedb/blob/main/tests/README.md

It seems that the create flow statement randomly fails.

[tisonkun]

@irenjj Thanks for your contribution! Would you share your email address to me (by email to tison@greptime.com)?

I'd like to send you a letter for further engagement :D

[irenjj]

@irenjj Thanks for your contribution! Would you share your email address to me (by email to tison@greptime.com)?

I'd like to send you a letter for further engagement :D

Sure! I've already sent the email.