feat: integrate Azure storage handling in migration process; update transformers and job processing logic

.atl/skill-registry.md

@@ -0,0 +1,24 @@
+# Skill Registry — go-migrate
+
+Generated: 2026-04-21
+
+## Compact Rules
+
+### Go conventions
+- Use existing error wrapping pattern: `fmt.Errorf("context: %w", err)`
+- Channel-based pipeline — keep goroutine lifecycle clean (close channels in correct order)
+- No comments unless non-obvious WHY; no docstrings
+- Prefer named returns only when it aids clarity in short functions
+- Use `strings.EqualFold` for case-insensitive column name comparison
+
+### Project conventions
+- Config structs live in `internal/app/config/`
+- ETL interfaces live in `internal/app/etl/types.go`
+- Transformer implementations in `internal/app/etl/transformers/`
+- Azure operations via `internal/app/azure/main.go`
+- Per-job transformer creation (not shared) when job has storage config
+
+## User Skills
+| Trigger | Skill |
+|---------|-------|
+| sdd-* | SDD workflow skills |

cmd/go_migrate/main.go

@@ -5,12 +5,12 @@ import (
 	"sync"
 	"time"
 
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/azure"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
-	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/db-wrapper"
+	dbwrapper "git.ksdemosapps.com/kylesoda/go-migrate/internal/app/db-wrapper"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/extractors"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/loaders"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/table_analyzers"
-	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/transformers"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/sync/errgroup"
@@ -119,9 +119,17 @@ func processMigrationJobs(
 	sourceTableAnalyzer := table_analyzers.NewMssqlTableAnalyzer(sourceDb)
 	targetTableAnalyzer := table_analyzers.NewPostgresTableAnalyzer(targetDb)
 	extractor := extractors.NewMssqlExtractor(sourceDb)
-	transformer := transformers.NewMssqlTransformer()
 	loader := loaders.NewGenericLoader(targetDb)
 
+	var azureClient *azure.Client
+	if config.App.AzureStorage.Enabled {
+		var err error
+		azureClient, err = azure.NewClient(config.App.AzureStorage)
+		if err != nil {
+			log.Fatalf("Failed to create Azure storage client: %v", err)
+		}
+	}
+
 	for i := range maxParallelWorkers {
 		wgJobs.Go(func() {
 			for job := range chJobs {
@@ -132,7 +140,7 @@ func processMigrationJobs(
 					sourceTableAnalyzer,
 					targetTableAnalyzer,
 					extractor,
-					transformer,
+					azureClient,
 					loader,
 					job,
 					targetDb.GetDialect(),

cmd/go_migrate/process.go

@@ -7,12 +7,14 @@ import (
 	"sync/atomic"
 	"time"
 
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/azure"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/custom_errors"
 	dbwrapper "git.ksdemosapps.com/kylesoda/go-migrate/internal/app/db-wrapper"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/extractors"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/table_analyzers"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/transformers"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/sync/errgroup"
@@ -38,11 +40,12 @@ func processMigrationJob(
 	sourceTableAnalyzer etl.TableAnalyzer,
 	targetTableAnalyzer etl.TableAnalyzer,
 	extractor etl.Extractor,
-	transformer etl.Transformer,
+	azureClient *azure.Client,
 	loader etl.Loader,
 	job config.Job,
 	targetDbType string,
 ) models.JobResult {
+	transformer := transformers.NewMssqlTransformer(job.ToStorage, job.SourceTable, azureClient)
 	localCtx, cancel := context.WithCancel(ctx)
 	defer cancel()
 

internal/app/azure/main.go

@@ -66,3 +66,22 @@ func (c *Client) UploadBuffer(ctx context.Context, containerName, blobPath strin
 	}
 	return nil
 }
+
+func (c *Client) UploadAndGetURL(ctx context.Context, blobPath string, buffer []byte) (string, error) {
+	if blobPath == "" || buffer == nil {
+		return "", ErrInvalidInput
+	}
+
+	fullPath := blobPath
+	if c.azureStorageConfig.Prefix != "" {
+		fullPath, _ = url.JoinPath(c.azureStorageConfig.Prefix, blobPath)
+	}
+
+	if err := c.UploadBuffer(ctx, c.azureStorageConfig.Container, fullPath, buffer); err != nil {
+		return "", err
+	}
+
+	blobEndpoint, _ := url.JoinPath(c.azureStorageConfig.ServiceURL, c.azureStorageConfig.AccountName)
+	blobURL, _ := url.JoinPath(blobEndpoint, c.azureStorageConfig.Container, fullPath)
+	return blobURL, nil
+}

internal/app/etl/transformers/mssql.go

@@ -3,18 +3,32 @@ package transformers
 import (
 	"context"
 	"errors"
+	"fmt"
+	"strings"
 	"sync"
 	"time"
 
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/azure"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/custom_errors"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
+	"github.com/google/uuid"
+	log "github.com/sirupsen/logrus"
 )
 
-type MssqlTransformer struct{}
+type MssqlTransformer struct {
+	toStorage   config.ToStorageConfig
+	sourceTable config.SourceTableInfo
+	azureClient *azure.Client
+}
 
-func NewMssqlTransformer() etl.Transformer {
-	return &MssqlTransformer{}
+func NewMssqlTransformer(toStorage config.ToStorageConfig, sourceTable config.SourceTableInfo, azureClient *azure.Client) etl.Transformer {
+	return &MssqlTransformer{
+		toStorage:   toStorage,
+		sourceTable: sourceTable,
+		azureClient: azureClient,
+	}
 }
 
 func computeTransformationPlan(columns []models.ColumnType) []etl.ColumnTransformPlan {
@@ -60,6 +74,63 @@ func computeTransformationPlan(columns []models.ColumnType) []etl.ColumnTransfor
 	return plan
 }
 
+func computeStorageTransformationPlan(
+	ctx context.Context,
+	azureClient *azure.Client,
+	toStorage config.ToStorageConfig,
+	sourceColumns []models.ColumnType,
+	sourceTable config.SourceTableInfo,
+) []etl.ColumnTransformPlan {
+	if azureClient == nil || len(toStorage.Columns) == 0 {
+		return nil
+	}
+
+	colIndex := make(map[string]int, len(sourceColumns))
+	for i, col := range sourceColumns {
+		colIndex[strings.ToUpper(col.Name())] = i
+	}
+
+	var plan []etl.ColumnTransformPlan
+	for _, storageCol := range toStorage.Columns {
+		if storageCol.Mode != "REFERENCE_ONLY" {
+			log.Warnf("to_storage: unsupported mode %q for column %s — skipping", storageCol.Mode, storageCol.Source)
+			continue
+		}
+
+		idx, ok := colIndex[strings.ToUpper(storageCol.Source)]
+		if !ok {
+			log.Warnf("to_storage: source column %q not found in source schema — skipping", storageCol.Source)
+			continue
+		}
+
+		sourceColName := storageCol.Source
+		schema := sourceTable.Schema
+		table := sourceTable.Table
+
+		plan = append(plan, etl.ColumnTransformPlan{
+			Index: idx,
+			Fn: func(v any) (any, error) {
+				if v == nil {
+					return nil, nil
+				}
+				b, ok := v.([]byte)
+				if !ok {
+					log.Warnf("to_storage: expected []byte for %s.%s.%s, got %T — passing through",
+						schema, table, sourceColName, v)
+					return v, nil
+				}
+				blobPath := fmt.Sprintf("%s/%s/%s/%s.bin", schema, table, sourceColName, uuid.New().String())
+				blobURL, err := azureClient.UploadAndGetURL(ctx, blobPath, b)
+				if err != nil {
+					return nil, fmt.Errorf("uploading %s.%s.%s: %w", schema, table, sourceColName, err)
+				}
+				return blobURL, nil
+			},
+		})
+	}
+	return plan
+}
+
 const processBatchCtxCheck = 4096
 
 func (mssqlTr *MssqlTransformer) ProcessBatch(
@@ -100,6 +171,8 @@ func (mssqlTr *MssqlTransformer) Exec(
 	wgActiveBatches *sync.WaitGroup,
 ) {
 	transformationPlan := computeTransformationPlan(columns)
+	storagePlan := computeStorageTransformationPlan(ctx, mssqlTr.azureClient, mssqlTr.toStorage, columns, mssqlTr.sourceTable)
+	transformationPlan = append(transformationPlan, storagePlan...)
 
 	for {
 		if ctx.Err() != nil {