feat: ✨ PostgreSQL connections opened by relspec set application_name by default to relspecgo/<version>

README.md

@@ -42,6 +42,11 @@ relspec convert --from pgsql --from-conn "postgres://..." --to sqlite --to-path
 relspec convert --from json --from-list "a.json,b.json" --to yaml --to-path merged.yaml
 ```
 
+PostgreSQL connections opened by relspec set `application_name` by default to
+`relspecgo/<version>` (with component suffixes internally, e.g. readers/writers).
+If you need a custom value, provide `application_name` explicitly in the connection
+string query parameters.
+
 ### `merge` — Additive schema merge (never modifies existing items)
 
 ```bash

pkg/pgsql/connection_test.go

@@ -0,0 +1,53 @@
+package pgsql
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestBuildApplicationName_IncludesVersion(t *testing.T) {
+	got := BuildApplicationName("")
+	if !strings.HasPrefix(got, "relspecgo/") {
+		t.Fatalf("BuildApplicationName() = %q, expected prefix relspecgo/", got)
+	}
+}
+
+func TestBuildApplicationName_IncludesComponent(t *testing.T) {
+	got := BuildApplicationName("reader-pgsql")
+	if !strings.Contains(got, ":reader-pgsql") {
+		t.Fatalf("BuildApplicationName(component) = %q, expected component suffix", got)
+	}
+}
+
+func TestBuildApplicationName_RespectsPostgresLengthLimit(t *testing.T) {
+	got := BuildApplicationName(strings.Repeat("x", 200))
+	if len(got) > 63 {
+		t.Fatalf("BuildApplicationName() length = %d, expected <= 63", len(got))
+	}
+}
+
+func TestParseConfigWithApplicationName_AddsWhenMissing(t *testing.T) {
+	cfg, err := ParseConfigWithApplicationName("postgres://user:pass@localhost:5432/db", "reader-pgsql")
+	if err != nil {
+		t.Fatalf("ParseConfigWithApplicationName() error = %v", err)
+	}
+
+	appName := cfg.RuntimeParams["application_name"]
+	if appName == "" {
+		t.Fatal("expected application_name to be set")
+	}
+	if !strings.HasPrefix(appName, "relspecgo/") {
+		t.Fatalf("application_name = %q, expected relspecgo/<version> prefix", appName)
+	}
+}
+
+func TestParseConfigWithApplicationName_PreservesExplicitValue(t *testing.T) {
+	cfg, err := ParseConfigWithApplicationName("postgres://user:pass@localhost:5432/db?application_name=custom-app", "reader-pgsql")
+	if err != nil {
+		t.Fatalf("ParseConfigWithApplicationName() error = %v", err)
+	}
+
+	if got := cfg.RuntimeParams["application_name"]; got != "custom-app" {
+		t.Fatalf("application_name = %q, expected %q", got, "custom-app")
+	}
+}

pkg/readers/pgsql/README.md

@@ -89,6 +89,10 @@ postgres://user@localhost/mydb?sslmode=disable
 postgres://user:pass@db.example.com:5432/production?sslmode=require
 ```
 
+By default, relspec sets `application_name` to `relspecgo/<version>` for PostgreSQL
+sessions so they are identifiable in `pg_stat_activity`. If you provide
+`application_name` in the connection string, your explicit value is preserved.
+
 ## Extracted Information
 
 ### Tables

pkg/readers/pgsql/reader.go

@@ -5,10 +5,11 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/jackc/pgx/v5"
+
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
 	"git.warky.dev/wdevs/relspecgo/pkg/pgsql"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers"
-	"github.com/jackc/pgx/v5"
 )
 
 // Reader implements the readers.Reader interface for PostgreSQL databases

pkg/writers/sqlexec/writer.go

@@ -8,6 +8,7 @@ import (
 	"github.com/jackc/pgx/v5"
 
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/pgsql"
 	"git.warky.dev/wdevs/relspecgo/pkg/writers"
 )
 
@@ -42,7 +43,7 @@ func (w *Writer) WriteDatabase(db *models.Database) error {
 
 	// Connect to database
 	ctx := context.Background()
-	conn, err := pgx.Connect(ctx, connString)
+	conn, err := pgsql.Connect(ctx, connString, "writer-sqlexec")
 	if err != nil {
 		return fmt.Errorf("failed to connect to database: %w", err)
 	}
@@ -72,7 +73,7 @@ func (w *Writer) WriteSchema(schema *models.Schema) error {
 
 	// Connect to database
 	ctx := context.Background()
-	conn, err := pgx.Connect(ctx, connString)
+	conn, err := pgsql.Connect(ctx, connString, "writer-sqlexec")
 	if err != nil {
 		return fmt.Errorf("failed to connect to database: %w", err)
 	}