initial database connection and migration

db/.gitignore

@@ -0,0 +1 @@
+_data/

db/compose.yml

@@ -0,0 +1,13 @@
+
+version: "3"
+
+services:
+
+  postgres:
+    image: postgres:11
+    ports:
+      - 5432:5432
+    environment:
+      POSTGRES_PASSWORD: postgres
+    volumes:
+      - ./_data:/var/lib/postgresql/data

db/init.sh

@@ -0,0 +1,70 @@
+#!/usr/bin/env sh
+
+######################################################################
+# @author      : annika
+# @file        : init
+# @created     : Tuesday Jan 11, 2022 15:35:20 CET
+# @description :  Initialize the database
+######################################################################
+
+if [ -z $PSQL ]; then
+    PSQL="psql"
+fi
+
+if [ -z $PGHOST ]; then
+    export PGHOST="localhost"
+fi
+
+if [ -z $PGPORT ]; then
+    export PGPORT="5432"
+fi
+
+if [ -z $PGDATABASE ]; then
+    export PGDATABASE="alice"
+fi
+
+if [ -z $PGUSER ]; then
+    export PGUSER="postgres"
+fi
+
+if [ -z $PGPASSWORD ]; then
+    export PGPASSWORD="postgres"
+fi
+
+## Commandline opts: 
+OPT_USAGE=0
+OPT_TESTING=0
+OPT_CLEAR=0
+
+while [ $# -gt 0 ]; do
+  case "$1" in
+    -h) OPT_USAGE=1 ;;
+    -t) OPT_TESTING=1 ;;
+    -c) OPT_CLEAR=1 ;;
+  esac
+  shift
+done
+
+if [ $OPT_USAGE -eq 1 ]; then
+    echo "Options:"
+    echo "   -h     Show this helpful text"
+    echo "   -c     Drop and create the database"
+    echo "   -t     Make a test database"
+    exit
+fi
+
+if [ $OPT_TESTING -eq 1 ]; then
+    echo "++ using test database"
+    NAME="${PGDATABASE}_test"
+    export PGDATABASE=$NAME
+fi
+
+if [ $OPT_CLEAR -eq 1 ]; then
+    echo "++ clearing database"
+    $PSQL template1 -c "DROP DATABASE $PGDATABASE"
+    $PSQL template1 -c "CREATE DATABASE $PGDATABASE"
+fi
+######################################################################
+
+
+

pkg/store/backends/postgres/connection.go

@@ -10,11 +10,6 @@ import (
 )
 
 var (
-	// ErrNotInitialized will be returned if the
-	// database pool is accessed before initializing using
-	// Connect.
-	ErrNotInitialized = errors.New("store not initialized, pool not ready")
-
 	// ErrMaxConnsUnconfigured will be returned, if the
 	// the maximum connections are zero.
 	ErrMaxConnsUnconfigured = errors.New("MaxConns not configured")

pkg/store/backends/postgres/connection_test.go

@@ -0,0 +1,46 @@
+package postgres
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/jackc/pgx/v4/pgxpool"
+)
+
+// ConnectTest uses defaults for the connection
+// environment variable is not set.
+func ConnectTest() *pgxpool.Pool {
+	ctx := context.Background()
+	url := os.Getenv("ALICE_TEST_DB_URL")
+	if url == "" {
+		url = "postgres://postgres:postgres@localhost:5432/alice_test"
+	}
+	p, err := Connect(ctx, &ConnectOpts{
+		URL:      url,
+		MinConns: 2,
+		MaxConns: 16})
+	if err != nil {
+		panic(err)
+	}
+
+	m := NewManager(p)
+	err = m.Initialize(ctx)
+	if err != nil {
+		panic(err)
+	}
+
+	return p
+}
+
+func TestInitialize(t *testing.T) {
+	p := ConnectTest()
+	m := NewManager(p)
+	s := m.Status(context.Background())
+	if s.Error != nil {
+		t.Error(s.Error)
+	}
+	if s.Migrated == false {
+		t.Error("schema is not migrated, current:", s.SchemaVersion)
+	}
+}

pkg/store/backends/postgres/manager.go

@@ -0,0 +1,102 @@
+package postgres
+
+import (
+	"context"
+	_ "embed" // embed schema
+	"log"
+	"time"
+
+	"github.com/jackc/pgx/v4/pgxpool"
+)
+
+// Include the schema through embedding
+//go:embed schema.sql
+var schema string
+
+// CurrentSchemaVersion is the current version of the schema
+const CurrentSchemaVersion = 1
+
+var (
+// ErrNotInitialized is returned when the database
+// schema is not migrated yet
+)
+
+// Status is the database / store status
+type Status struct {
+	Migrated        bool      `json:"migrated"`
+	SchemaVersion   int       `json:"schema_version"`
+	SchemaAppliedAt time.Time `json:"schema_applied_at"`
+	Error           error     `json:"error"`
+}
+
+// Log writes the status into the log
+func (s *Status) Log() {
+	log.Println(
+		"Database migrated:", s.Migrated)
+	log.Println(
+		"Schema version:", s.SchemaVersion,
+		"applied at:", s.SchemaAppliedAt)
+}
+
+// The Manager supervises the database. It can migrate the
+// schema and retrieve a status.
+type Manager struct {
+	pool *pgxpool.Pool
+}
+
+// NewManager creates a new database manager
+func NewManager(pool *pgxpool.Pool) *Manager {
+	return &Manager{
+		pool: pool,
+	}
+}
+
+// Start the background jobs for database management
+func (m *Manager) Start(ctx context.Context) {
+	m.Status(ctx).Log()
+}
+
+// Status retrieves the current schema version
+// and checks if migrated. In case an error occures,
+// it will be included in the result.
+func (m *Manager) Status(ctx context.Context) *Status {
+	status := &Status{}
+	qry := `
+		SELECT version, applied_at FROM __meta__
+		 ORDER BY version DESC
+		 LIMIT 1
+	`
+	err := m.pool.QueryRow(ctx, qry).Scan(
+		&status.SchemaVersion,
+		&status.SchemaAppliedAt,
+	)
+	if err != nil {
+		status.Error = err
+		return status
+	}
+
+	// Is the database migrated?
+	status.Migrated = CurrentSchemaVersion == status.SchemaVersion
+
+	return status
+}
+
+// Migrate applies the database intialisation script if required.
+func (m *Manager) Migrate(ctx context.Context) error {
+	s := m.Status(ctx)
+	if s.Migrated {
+		return nil
+	}
+
+	return m.Initialize(ctx)
+}
+
+// Initialize will apply the database schema. This will clear the
+// database. However for now we treat the state as disposable.
+func (m *Manager) Initialize(ctx context.Context) error {
+	_, err := m.pool.Exec(ctx, schema)
+	if err != nil {
+		return err
+	}
+	return nil
+}

pkg/store/backends/postgres/neighbors_backend.go

@@ -0,0 +1,33 @@
+package postgres
+
+import (
+	"context"
+
+	"github.com/alice-lg/alice-lg/pkg/api"
+	"github.com/jackc/pgx/v4/pgxpool"
+)
+
+// NeighborsBackend implements a neighbors store
+// using a postgres database
+type NeighborsBackend struct {
+	pool *pgxpool.Pool
+}
+
+// NewNeighborsBackend initializes the backend
+// with a pool.
+func NewNeighborsBackend(pool *pgxpool.Pool) *NeighborsBackend {
+	b := &NeighborsBackend{
+		pool: pool,
+	}
+	return b
+}
+
+// SetNeighbors updates the current neighbors of
+// a route server identified by sourceID
+func (b *NeighborsBackend) SetNeighbors(
+	ctx context.Context,
+	sourceID string,
+	neighbors api.Neighbors,
+) error {
+	return nil
+}

pkg/store/backends/postgres/schema.sql

@@ -5,9 +5,14 @@
 -- ----------------------
 --
 -- %% Author:      annika
--- %% Description: Create alice-lg db schema.
+-- %% Description: Apply alice-lg db schema.
 --
 
+-- Clear state
+DROP TABLE IF EXISTS routes;
+DROP TABLE IF EXISTS neighbors;
+DROP TABLE IF EXISTS __meta__;
+
 -- Neighbors
 CREATE TABLE neighbors (
     id    VARCHAR(255) NOT NULL PRIMARY KEY,
@@ -19,7 +24,7 @@ CREATE TABLE neighbors (
     neighbor     jsonb NOT NULL,
 
     -- Timestamps
-    updated_at  TIMESTAMP  NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at  TIMESTAMP  NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
 CREATE INDEX idx_neighbors_rs_id 
@@ -39,7 +44,7 @@ CREATE TABLE routes (
     route         jsonb        NOT NULL,
 
     -- Timestamps
-    updated_at  TIMESTAMP  NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at  TIMESTAMP  NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
 CREATE INDEX idx_routes_network ON routes ( network );