feat: add native PostgreSQL backend and external plugin architecture#621
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maelanjais wants to merge 13 commits into
Open
feat: add native PostgreSQL backend and external plugin architecture#621maelanjais wants to merge 13 commits into
maelanjais wants to merge 13 commits into
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… for external backends
…CI pipeline with postgres integration test
…I, remove broken CI workflow
…nt-driven updates
- Restore configSources/shouldApplyTOML/AfterApply for proper CLI > env > TOML precedence resolution (was lost when postgres/plugin backends were added) - Add applyBackendDefaults() and move per-backend node defaults out of Run() to match upstream pattern; add postgres to the defaults switch - Add Database and PluginPath fields to TOMLConfig so they are configurable via confd.toml - Restore TestLoadConfigFile_ExplicitDefaultSourcesOverrideTOML and TestApplyBackendDefaults test coverage - Bump Go from 1.25.8 to 1.26 / toolchain go1.26.2 in go.mod - Update Go version pins to 1.26.3 in all GitHub Actions workflows, Dockerfile.build, and .tool-versions - Restore v0.41.2 section to CHANGELOG (was absent due to rebase on older base) - Rewrite README.md to match upstream format while documenting the new PostgreSQL (with LISTEN/NOTIFY watch) and Plugin backends - Promote hashicorp/go-plugin to a direct dependency in go.mod (go mod tidy)
Owner
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@maelanjais thanks for the contribution! I would be ok with adding PostgreSQL as a backend, but I'm not sure how much value it would actually bring. Could you minimally split these two features into their own PRs so that the can be assessed independently? |
This was referenced Jun 8, 2026
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Summary
This PR adds two new backend types to confd:
Native PostgreSQL backend (
postgres) powered bypgx/v5, with real-time change notification viaLISTEN/NOTIFY(eliminating polling in watch mode), support for SQL Views to map confd keys to existing businesstables, and standard username/password authentication.
External plugin backend (
plugin) using HashiCorp go-plugin, allowing operators to load any custom backend at runtime as a standalone binary without recompiling confd. Areference implementation (
cmd/confd-plugin-postgres) ships as a PostgreSQL plugin example.Changes
New packages
pkg/backends/postgres/— PostgreSQLStoreClientwithGetValues(prefix scan viaLIKE) andWatchPrefix(dedicatedLISTEN confd_updateconnection)pkg/backends/plugin/— go-plugin client that launches an external binary and proxiesStoreClientcalls over RPCpkg/backends/plugin/api/— shared RPC DTOs,BackendProviderinterface,BackendRPCClient/BackendRPCServer, andConfdBackendPluginboilerplatecmd/confd-plugin-postgres/— reference PostgreSQL plugin binary (demonstrates the plugin SDK)CLI additions
confd postgressubcommand (--node,--username,--password,--database,--table)confd pluginsubcommand (--plugin-path)pkg/backends/client.goandpkg/backends/config.goConfig file support
databaseandplugin_pathfields added toTOMLConfigso both backends can be configured fromconfd.tomlTests
pkg/backends/postgres/client_test.go)pkg/backends/plugin/api/api_test.go)Documentation
PLUGIN_ARCHITECTURE.md— plugin SDK specification and implementation guidePLUGIN_DEMO.md— end-to-end demo with Docker ComposePOSTGRES_DEMO.md— PostgreSQL setup, SQL Views, LISTEN/NOTIFY walkthroughREADME.mdupdated to list the two new backends in the feature list and backend tableTest plan
go test ./...passes (all 26 packages)make buildsucceedsgo build ./cmd/confd-plugin-postgressucceedsTestLoadConfigFile_ExplicitDefaultSourcesOverrideTOMLPOSTGRES_DEMO.md)confd-plugin-postgresand a running Postgres instance (seePLUGIN_DEMO.md)