Fix Idempotency of base.sql and tests thereof

This commit fixes the idempotency of base.sql (we forgot an OR REPLACE)
and also fixes the tests that migrating to the same version works; we
had been using an artificial version number which didn't conform to our
versioning scheme, and thus broke the migration path.

Dockerfile

@@ -10,7 +10,7 @@ RUN apk update && apk add --no-cache git \
     && go mod download \
     && GIT_COMMIT=$(git rev-list -1 HEAD) \
     && CGO_ENABLED=0 go build -a \
-    --ldflags '-w' --ldflags "-X main.CommitHash=$GIT_COMMIT" \
+    --ldflags '-w' --ldflags "-X version.CommitHash=$GIT_COMMIT" \
     -o /go/timescale-prometheus ./cmd/timescale-prometheus
 
 # Final image

cmd/timescale-prometheus/main.go

@@ -30,6 +30,7 @@ import (
 	"github.com/timescale/timescale-prometheus/pkg/pgmodel"
 	"github.com/timescale/timescale-prometheus/pkg/query"
 	"github.com/timescale/timescale-prometheus/pkg/util"
+	"github.com/timescale/timescale-prometheus/pkg/version"
 )
 
 type config struct {
@@ -149,16 +150,16 @@ func init() {
 func main() {
 	cfg, err := parseFlags()
 	if err != nil {
-		fmt.Println("Version: ", Version, "Commit Hash: ", CommitHash)
+		fmt.Println("Version: ", version.Version, "Commit Hash: ", version.CommitHash)
 		fmt.Println("Fatal error: cannot parse flags ", err)
 	}
 	err = log.Init(cfg.logLevel)
 	if err != nil {
-		fmt.Println("Version: ", Version, "Commit Hash: ", CommitHash)
+		fmt.Println("Version: ", version.Version, "Commit Hash: ", version.CommitHash)
 		fmt.Println("Fatal error: cannot start logger", err)
 		os.Exit(1)
 	}
-	log.Info("msg", "Version:"+Version+"; Commit Hash: "+CommitHash)
+	log.Info("msg", "Version:"+version.Version+"; Commit Hash: "+version.CommitHash)
 	log.Info("config", util.MaskPassword(fmt.Sprintf("%+v", cfg)))
 
 	elector, err = initElector(cfg)
@@ -374,7 +375,7 @@ func migrate(cfg *pgclient.Config) error {
 	}
 	defer db.Close()
 
-	err = pgmodel.Migrate(db, pgmodel.VersionInfo{Version: Version, CommitHash: CommitHash})
+	err = pgmodel.Migrate(db, pgmodel.VersionInfo{Version: version.Version, CommitHash: version.CommitHash})
 
 	if err != nil {
 		return fmt.Errorf("Error while trying to migrate DB: %w", err)

pkg/pgmodel/end_to_end_tests/main_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/timescale/timescale-prometheus/pkg/internal/testhelpers"
 	"github.com/timescale/timescale-prometheus/pkg/log"
 	"github.com/timescale/timescale-prometheus/pkg/pgmodel"
+	"github.com/timescale/timescale-prometheus/pkg/version"
 
 	_ "github.com/jackc/pgx/v4/stdlib"
 
@@ -108,7 +109,7 @@ func performMigrate(t testing.TB, connectURL string) {
 		t.Fatal(err)
 	}
 	defer migratePool.Close()
-	err = Migrate(migratePool, pgmodel.VersionInfo{Version: expectedVersion, CommitHash: "azxtestcommit"})
+	err = Migrate(migratePool, pgmodel.VersionInfo{Version: version.Version, CommitHash: "azxtestcommit"})
 	if err != nil {
 		t.Fatal(err)
 	}

pkg/pgmodel/end_to_end_tests/migrate_test.go

@@ -13,24 +13,21 @@ import (
 	"github.com/timescale/timescale-prometheus/pkg/internal/testhelpers"
 	"github.com/timescale/timescale-prometheus/pkg/pgmodel"
 	"github.com/timescale/timescale-prometheus/pkg/pgmodel/test_migrations"
-)
-
-const (
-	expectedVersion = "0.0.1-alpha"
+	"github.com/timescale/timescale-prometheus/pkg/version"
 )
 
 func TestMigrate(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping integration test")
 	}
 	withDB(t, *testDatabase, func(db *pgxpool.Pool, t testing.TB) {
-		var version string
-		err := db.QueryRow(context.Background(), "SELECT version FROM prom_schema_migrations").Scan(&version)
+		var dbVersion string
+		err := db.QueryRow(context.Background(), "SELECT version FROM prom_schema_migrations").Scan(&dbVersion)
 		if err != nil {
 			t.Fatal(err)
 		}
-		if version != expectedVersion {
-			t.Errorf("Version unexpected:\ngot\n%s\nwanted\n%s", version, expectedVersion)
+		if dbVersion != version.Version {
+			t.Errorf("Version unexpected:\ngot\n%s\nwanted\n%s", dbVersion, version.Version)
 		}
 	})
 }

pkg/pgmodel/migrations/sql/idempotent/base.sql

@@ -964,7 +964,7 @@ LANGUAGE SQL STABLE;
 GRANT EXECUTE ON FUNCTION SCHEMA_CATALOG.get_metrics_that_need_drop_chunk() TO prom_reader;
 
 --public procedure to be called by cron
-CREATE PROCEDURE SCHEMA_PROM.drop_chunks()
+CREATE OR REPLACE PROCEDURE SCHEMA_PROM.drop_chunks()
 AS $$
 DECLARE
     r RECORD;

cmd/timescale-prometheus/version_info.go → pkg/version/version.go

@@ -1,4 +1,4 @@
-package main
+package version
 
 var (
 	// Rules for Versioning: