go.charczuk.com@v0.0.0-20240327042549-bc490516bd1a/sdk/apputil/db_entrypoint.go (about)

     1  /*
     2  
     3  Copyright (c) 2023 - Present. Will Charczuk. All rights reserved.
     4  Use of this source code is governed by a MIT license that can be found in the LICENSE file at the root of the repository.
     5  
     6  */
     7  
     8  package apputil
     9  
    10  import (
    11  	"context"
    12  	"flag"
    13  	"strings"
    14  
    15  	"go.charczuk.com/sdk/cliutil"
    16  	"go.charczuk.com/sdk/configutil"
    17  	"go.charczuk.com/sdk/db"
    18  	"go.charczuk.com/sdk/logutil"
    19  )
    20  
    21  // DBEntryPointConfigProvider is a type that can provide
    22  // an entrypoint config.
    23  type DBEntryPointConfigProvider interface {
    24  	LoggerProvider
    25  	DBProvider
    26  	MetaProvider
    27  }
    28  
    29  // EntryPoint is a top level handler for a database backed app.
    30  //
    31  // It handles reading the config, setting up the logger,
    32  // opening the database connection, and based on comandline
    33  // flags handling calling specific handlers for initializing the
    34  // database and applying migrations on start.
    35  type DBEntryPoint[T DBEntryPointConfigProvider] struct {
    36  	Setup   func(context.Context, T) error
    37  	Migrate func(context.Context, T, *db.Connection) error
    38  	Start   func(context.Context, T, *db.Connection) error
    39  
    40  	config              T
    41  	flagDatabaseSetup   bool
    42  	flagDatabaseMigrate bool
    43  	flagStart           bool
    44  }
    45  
    46  // Init should be run before `Run` and registers flags and the like.
    47  func (e *DBEntryPoint[T]) Init() {
    48  	flag.BoolVar(&e.flagDatabaseSetup, "db-setup", false, "if we should run the first time setup for the database")
    49  	flag.BoolVar(&e.flagDatabaseMigrate, "db-migrate", false, "if we should apply database migrations")
    50  	flag.BoolVar(&e.flagStart, "start", true, "if we should start the server (false will exit after other steps complete)")
    51  	flag.Parse()
    52  }
    53  
    54  // Main is the actual function that needs to be called in Main.
    55  func (e *DBEntryPoint[T]) Main() {
    56  	ctx := context.Background()
    57  	configPaths := configutil.MustRead(&e.config)
    58  	log := logutil.New(
    59  		logutil.OptConfig(e.config.GetLogger()),
    60  	)
    61  	ctx = logutil.WithLogger(ctx, log)
    62  	if len(configPaths) > 0 {
    63  		logutil.Infof(log, "using config path(s): %s", strings.Join(configPaths, ", "))
    64  	} else {
    65  		logutil.Infof(log, "using environment resolved config")
    66  	}
    67  	if e.flagDatabaseSetup && e.Setup != nil {
    68  		logutil.Infof(log, "running first time database setup: %s", e.config.GetDB().Database)
    69  		if err := e.Setup(ctx, e.config); err != nil {
    70  			cliutil.Fatal(err)
    71  		}
    72  		logutil.Infof(log, "running first time database setup complete")
    73  	} else {
    74  		logutil.Debug(log, "skipping running first time database setup")
    75  	}
    76  	conn, err := db.New(
    77  		db.OptConfig(e.config.GetDB()),
    78  		db.OptLog(log),
    79  	)
    80  	if err != nil {
    81  		cliutil.Fatal(err)
    82  	}
    83  	if err = conn.Open(); err != nil {
    84  		cliutil.Fatal(err)
    85  	}
    86  	defer conn.Close()
    87  
    88  	if e.flagDatabaseMigrate && e.Migrate != nil {
    89  		logutil.Info(log, "applying database migrations")
    90  		if err := e.Migrate(ctx, e.config, conn); err != nil {
    91  			cliutil.Fatal(err)
    92  		}
    93  		logutil.Info(log, "applying database migrations complete")
    94  	} else {
    95  		logutil.Debug(log, "skipping database migrations")
    96  	}
    97  
    98  	if e.config.GetMeta().IsProdlike() {
    99  		logutil.Debugf(log, "using database dsn: %s", conn.CreateLoggingDSN())
   100  	}
   101  
   102  	if e.flagStart && e.Start != nil {
   103  		if err := e.Start(ctx, e.config, conn); err != nil {
   104  			cliutil.Fatal(err)
   105  		}
   106  	}
   107  }