Added support for Postgres polling sources

2026-03-29 10:53:13 -05:00
parent 247937b65e
commit 5c1b28ee0a
7 changed files with 752 additions and 52 deletions
--- a/sources/postgres.go
+++ b/sources/postgres.go
@@ -0,0 +1,117 @@
+package sources
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+	"time"
+
+	"gitea.maximumdirect.net/ejr/feedkit/config"
+	pgconn "gitea.maximumdirect.net/ejr/feedkit/internal/postgres"
+)
+
+const defaultPostgresQueryTimeout = 30 * time.Second
+
+type postgresQueryDB interface {
+	QueryContext(ctx context.Context, query string, args ...any) (*sql.Rows, error)
+}
+
+var openPostgresQueryDB = func(ctx context.Context, cfg pgconn.ConnConfig) (postgresQueryDB, error) {
+	return pgconn.Open(ctx, cfg)
+}
+
+// PostgresQuerySource is a reusable helper for polling Postgres-backed sources.
+//
+// It centralizes generic source config parsing and query execution. Concrete
+// daemon sources remain responsible for SQL semantics, row scanning, cursoring,
+// and event construction.
+type PostgresQuerySource struct {
+	Driver       string
+	Name         string
+	SQL          string
+	QueryTimeout time.Duration
+
+	db postgresQueryDB
+}
+
+// NewPostgresQuerySource builds a generic Postgres polling helper from
+// SourceConfig.
+//
+// Required params:
+//   - params.uri
+//   - params.username
+//   - params.password
+//   - params.query
+//
+// Optional params:
+//   - params.query_timeout (default 30s)
+func NewPostgresQuerySource(driver string, cfg config.SourceConfig) (*PostgresQuerySource, error) {
+	name := strings.TrimSpace(cfg.Name)
+	if name == "" {
+		return nil, fmt.Errorf("%s: name is required", driver)
+	}
+	if cfg.Params == nil {
+		return nil, fmt.Errorf("%s %q: params are required (need params.uri, params.username, params.password, and params.query)", driver, cfg.Name)
+	}
+
+	uri, ok := cfg.ParamString("uri")
+	if !ok {
+		return nil, fmt.Errorf("%s %q: params.uri is required", driver, cfg.Name)
+	}
+	username, ok := cfg.ParamString("username")
+	if !ok {
+		return nil, fmt.Errorf("%s %q: params.username is required", driver, cfg.Name)
+	}
+	password, ok := cfg.ParamString("password")
+	if !ok {
+		return nil, fmt.Errorf("%s %q: params.password is required", driver, cfg.Name)
+	}
+	query, ok := cfg.ParamString("query")
+	if !ok {
+		return nil, fmt.Errorf("%s %q: params.query is required", driver, cfg.Name)
+	}
+
+	queryTimeout := defaultPostgresQueryTimeout
+	if _, exists := cfg.Params["query_timeout"]; exists {
+		var ok bool
+		queryTimeout, ok = cfg.ParamDuration("query_timeout")
+		if !ok || queryTimeout <= 0 {
+			return nil, fmt.Errorf("source %q: params.query_timeout must be a positive duration", cfg.Name)
+		}
+	}
+
+	db, err := openPostgresQueryDB(context.Background(), pgconn.ConnConfig{
+		URI:      uri,
+		Username: username,
+		Password: password,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("%s %q: open db: %w", driver, cfg.Name, err)
+	}
+
+	return &PostgresQuerySource{
+		Driver:       driver,
+		Name:         name,
+		SQL:          query,
+		QueryTimeout: queryTimeout,
+		db:           db,
+	}, nil
+}
+
+func (s *PostgresQuerySource) Query(ctx context.Context, args ...any) (*sql.Rows, error) {
+	queryCtx := ctx
+	if s.QueryTimeout > 0 {
+		if deadline, ok := ctx.Deadline(); !ok || time.Until(deadline) > s.QueryTimeout {
+			// We intentionally do not cancel this derived context here because the
+			// returned rows may still be reading from the database.
+			queryCtx, _ = context.WithTimeout(ctx, s.QueryTimeout)
+		}
+	}
+
+	rows, err := s.db.QueryContext(queryCtx, s.SQL, args...)
+	if err != nil {
+		return nil, fmt.Errorf("%s %q: query: %w", s.Driver, s.Name, err)
+	}
+	return rows, nil
+}