Feature: New driver - pg

[oscar60310]

Description

• Implement data source for Postgres.
• I changed the default data source to "mock" because it was "pg".
• Destroy the source stream when Koa destroyed the downstream, it's important for pg driver because it needs to release the connection to the pool.

Issue ticket number

closes #56

Additional Context

• I used a real pg server in docker to run the test, so our unit tests need Docker env to run.
• I changed the CI environment from docker to VM in order to run docker services

[codecov-commenter]

Codecov Report

Base: 92.52% // Head: 92.58% // Increases project coverage by +0.05% 🎉

Coverage data is based on head (b514d26) compared to base (46c0080).
Patch coverage: 95.23% of modified lines in pull request are covered.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop      #78      +/-   ##
===========================================
+ Coverage    92.52%   92.58%   +0.05%     
===========================================
  Files          245      248       +3     
  Lines         3533     3613      +80     
  Branches       446      453       +7     
===========================================
+ Hits          3269     3345      +76     
- Misses         179      183       +4     
  Partials        85       85              

Flag	Coverage Δ
build	94.54% <ø> (ø)
cli	88.96% <ø> (ø)
core	93.26% <100.00%> (ø)
extension-dbt	97.43% <ø> (ø)
extension-debug-tools	98.11% <ø> (ø)
extension-driver-duckdb	100.00% <ø> (ø)
extension-driver-pg	94.87% <94.87%> (?)
integration-testing	96.15% <ø> (ø)
serve	90.21% <100.00%> (+0.02%)	⬆️
test-utility	∅ <ø> (∅)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ckages/extension-driver-pg/src/lib/pgDataSource.ts	93.33% <93.33%> (ø)
packages/core/src/lib/data-source/index.ts	100.00% <100.00%> (ø)
packages/core/src/lib/data-source/mock.ts	42.85% <100.00%> (ø)
packages/extension-driver-pg/src/index.ts	100.00% <100.00%> (ø)
packages/extension-driver-pg/src/lib/typeMapper.ts	100.00% <100.00%> (ø)
...s/serve/src/models/extensions/responseFormatter.ts	100.00% <100.00%> (ø)

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[oscar60310]

@kokokuo I've solved the conflicts, and this PR is ready for review.

[kokokuo]

LGTM 👍 👍

[kokokuo]

@oscar60310, just have a question after I also develop another data source, why do we need to do the typeMapper and convert the postgres original type and snowflake to typescript matched type?

[oscar60310]

@oscar60310, just have a question after I also develop another data source, why do we need to do the typeMapper and convert the postgres original type and snowflake to typescript matched type?

For generating the response schema in the specification.
https://github.com/Canner/vulcan-sql/blob/develop/packages/build/src/lib/schema-parser/middleware/responseSampler.ts#L48-L64

PG (or other data sources) has lots of data types, e.g. int2, int4, etc., but our API spec only has some basic types: string, number, etc. So the connectors have to tell Vulcan core how should we map the corresponding types, that is, make the types simpler to understand.

[kokokuo]

@oscar60310, just have a question after I also develop another data source, why do we need to do the typeMapper and convert the postgres original type and snowflake to typescript matched type?

For generating the response schema in the specification.

https://github.com/Canner/vulcan-sql/blob/develop/packages/build/src/lib/schema-parser/middleware/responseSampler.ts#L48-L64

PG (or other data sources) has lots of data types, e.g. int2, int4, etc., but our API spec only has some basic types: string, number, etc. So the connectors have to tell Vulcan core how should we map the corresponding types, that is, make the types simpler to understand.

Thanks so much!!!! I'm working ClickHouse now, it really helpful for me to handle it 😀

Also cc @JSYOU, @onlyjackfrost, @andreashimin, @fredalai, and @wwwy3y3 to know the the reason.