feat: add PostgreSQL tracing support for sql and gorm

[wl2027]

Summary

This PR adds PostgreSQL tracing support to the SkyWalking Go agent for:

• database/sql with pgx/v5 stdlib
• gorm with gorm.io/driver/postgres

Included

• Add PostgreSQL SQL tracing support
• Add GORM PostgreSQL tracing support
• Add PostgreSQL SQL/GORM scenarios and tests

Scope

This PR focuses on these PostgreSQL paths:

• sql.Open("pgx", dsn)
• gorm.Open(postgres.Open(dsn), ...)

It does not yet cover stdlib.OpenDB(...), stdlib.OpenDBFromPool(...), or RegisterConnConfig()+sql.Open(...).

Verification

• go test ./plugins/sql/pgxstdlib ./plugins/gorm/entry ./plugins/gorm/postgres ./plugins/core/tracing
• bash test/plugins/run.sh postgres
• bash test/plugins/run.sh gorm-postgres

[Copilot]

Pull request overview

This PR adds PostgreSQL tracing support to the SkyWalking Go agent for database/sql (via pgx/v5/stdlib) and for GORM (via gorm.io/driver/postgres), and wires up new integration test scenarios to validate emitted spans.

Changes:

• Add a new sql/pgxstdlib plugin to extract PostgreSQL peer info from pgx DSNs and enable SQL span tagging.
• Add a new gorm/postgres plugin to extract PostgreSQL peer info from the GORM Postgres dialector/config and propagate it into the GORM entry plugin.
• Add Postgres + GORM-Postgres scenario apps and expected trace snapshots; include them in the workspace and CI plugin-test matrix.

Reviewed changes

Copilot reviewed 22 out of 28 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tools/go-agent/instrument/plugins/register.go	Registers the new PostgreSQL SQL + GORM instruments with the agent tool.
plugins/sql/pgxstdlib/instrument.go	Declares the pgx stdlib instrumentation point (Driver.OpenConnector).
plugins/sql/pgxstdlib/interceptor.go	Extracts PostgreSQL peer info from pgx DSN/config and stores it in runtime context for database/sql entry plugin.
plugins/sql/pgxstdlib/interceptor_test.go	Unit tests for DSN parsing and peer address formatting edge-cases.
plugins/sql/go.mod	Adds dependencies needed for pgx stdlib plugin + tests.
plugins/sql/go.sum	Locks new/updated dependencies for the SQL plugin module.
plugins/gorm/postgres/instrument.go	Declares GORM postgres driver instrumentation points (Open, New, struct enhance).
plugins/gorm/postgres/interceptor.go	Extracts peer info from GORM postgres dialector DSN / Conn and stores it on the dialector dynamic field.
plugins/gorm/postgres/interceptor_test.go	Unit tests for DSN parsing, multi-host, and SQL-Conn adaptation.
plugins/gorm/go.mod	Adds postgres driver + pgx dependencies for the GORM plugin module.
plugins/gorm/go.sum	Locks new/updated dependencies for the GORM plugin module.
plugins/gorm/entry/interceptor.go	Adds a nil guard when setting up DB info from the opened *gorm.DB.
plugins/gorm/entry/interceptor_test.go	Adds test coverage for PrepareStmt mode to ensure spans are still reported.
test/plugins/scenarios/postgres/plugin.yml	Defines the new postgres SQL scenario metadata and docker dependency.
test/plugins/scenarios/postgres/main.go	Scenario app exercising database/sql operations against Postgres via pgx stdlib.
test/plugins/scenarios/postgres/go.mod	Module definition for the postgres SQL scenario app.
test/plugins/scenarios/postgres/go.sum	Dependency lockfile for the postgres SQL scenario app.
test/plugins/scenarios/postgres/config/excepted.yml	Expected trace snapshot for the postgres SQL scenario.
test/plugins/scenarios/postgres/bin/startup.sh	Builds and runs the postgres SQL scenario app with SQL parameter collection enabled.
test/plugins/scenarios/gorm-postgres/plugin.yml	Defines the new gorm-postgres scenario metadata and docker dependency.
test/plugins/scenarios/gorm-postgres/main.go	Scenario app exercising GORM CRUD + prepared statements against Postgres.
test/plugins/scenarios/gorm-postgres/go.mod	Module definition for the gorm-postgres scenario app.
test/plugins/scenarios/gorm-postgres/go.sum	Dependency lockfile for the gorm-postgres scenario app.
test/plugins/scenarios/gorm-postgres/config/excepted.yml	Expected trace snapshot for the gorm-postgres scenario.
test/plugins/scenarios/gorm-postgres/bin/startup.sh	Builds and runs the gorm-postgres scenario app with GORM parameter collection enabled.
go.work	Adds the new scenario modules to the workspace.
docs/en/agent/support-plugins.md	Documents support/testing versions for GORM Postgres driver and pgx stdlib.
.github/workflows/plugin-tests.yaml	Adds postgres + gorm-postgres scenarios to CI plugin-test matrix.

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[mrproliu]

Generally LGTM, please fix the CI failure and above comments.

[mrproliu]

You have changed the max version of this framework, then please also add the version check in this plugin test.

[wl2027]

I reverted gorm back to v1.25.1 for now.

When I tried to extend the GORM test coverage to v1.25.10, I found that upstream GORM changed how LIMIT/OFFSET is generated. For example, LIMIT 1 becomes a parameterized LIMIT ? with 1 moved into the bound parameters. go-gorm/gorm#6806

The current plugin scenario excepted.yml does not seem to support covering these different but valid outputs in a single file. Should we enhance the excepted.yml matcher in a follow-up to handle this kind of case?

[wl2027]

Generally LGTM, please fix the CI failure and above comments.

The last CI failure is in the rocketmq scenario. From the logs, it looks more like an existing stability issue in that RocketMQ scenario than something introduced by this pr . Would you like me to follow up separately and work on that scenario?