refactor(backend): introduce dialect-aware LargeText and replace longtext (+call-site type adjustments). Part of kubeflow#12063 (kubeflow#12163)

Signed-off-by: kaikaila <[email protected]>

Author: kaikaila

backend/src/apiserver/config/config.go

@@ -141,7 +141,7 @@ func LoadSamples(resourceManager *resource.ResourceManager, sampleConfigPath str
 				p, configErr = resourceManager.CreatePipeline(&model.Pipeline{
 					Name:        cfg.Name,
 					DisplayName: pipelineDisplayName,
-					Description: cfg.Description,
+					Description: model.LargeText(cfg.Description),
 				})
 				if configErr != nil {
 					// Log the error but not fail. The API Server pod can restart and it could potentially cause
@@ -191,9 +191,9 @@ func LoadSamples(resourceManager *resource.ResourceManager, sampleConfigPath str
 					&model.PipelineVersion{
 						Name:         pvName,
 						DisplayName:  pvDisplayName,
-						Description:  pvDescription,
+						Description:  model.LargeText(pvDescription),
 						PipelineId:   p.UUID,
-						PipelineSpec: string(pipelineFile),
+						PipelineSpec: model.LargeText(string(pipelineFile)),
 					},
 				)
 				if configErr != nil {

backend/src/apiserver/model/common.go

@@ -0,0 +1,74 @@
+// Copyright 2025 The Kubeflow Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package model
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"fmt"
+
+	"gorm.io/gorm"
+	"gorm.io/gorm/schema"
+)
+
+// LargeText is a custom data type defined per GORM's recommendation for dialect-aware
+// large-text columns. It implements GormDBDataTypeInterface to return the appropriate
+// SQL type for each dialect (e.g., LONGTEXT for MySQL, TEXT for others).
+// For details, see https://gorm.io/docs/data_types.html#GormDataTypeInterface
+type LargeText string
+
+func (LargeText) GormDBDataType(db *gorm.DB, field *schema.Field) string {
+	switch db.Name() {
+	case "mysql":
+		return "LONGTEXT"
+	default:
+		return "TEXT"
+	}
+}
+
+func (lt LargeText) String() string {
+	return string(lt)
+}
+
+func (lt LargeText) Value() (driver.Value, error) {
+	return string(lt), nil
+}
+
+func (lt *LargeText) Scan(src any) error {
+	switch v := src.(type) {
+	case string:
+		*lt = LargeText(v)
+	case []byte:
+		*lt = LargeText(string(v))
+	case nil:
+		*lt = ""
+	default:
+		return fmt.Errorf("unsupported type %T for LargeText", v)
+	}
+	return nil
+}
+
+func (lt LargeText) MarshalJSON() ([]byte, error) {
+	return json.Marshal(string(lt))
+}
+
+func (lt *LargeText) UnmarshalJSON(b []byte) error {
+	var s string
+	if err := json.Unmarshal(b, &s); err != nil {
+		return err
+	}
+	*lt = LargeText(s)
+	return nil
+}

backend/src/apiserver/model/pipeline.go

@@ -41,11 +41,11 @@ type Pipeline struct {
 	// Even though Namespace rarely uses its full 63-character capacity in practice,
 	// MySQL calculates index length based on declared size, not actual content.
 	// Therefore, keeping Name at varchar(128) is a safe upper bound.
-	Name        string `gorm:"column:Name; not null; uniqueIndex:namespace_name; type:varchar(128);"` // Index improves performance of the List and Get queries
-	DisplayName string `gorm:"column:DisplayName; not null"`
-	Description string `gorm:"column:Description; type:longtext; not null"`
+	Name        string    `gorm:"column:Name; not null; uniqueIndex:namespace_name; type:varchar(128);"` // Index improves performance of the List and Get queries
+	DisplayName string    `gorm:"column:DisplayName; not null"`
+	Description LargeText `gorm:"column:Description; not null"`
 	// TODO(gkcalat): this is deprecated. Consider removing and adding data migration logic at the server startup.
-	Parameters string         `gorm:"column:Parameters; type:longtext;"`
+	Parameters LargeText      `gorm:"column:Parameters;"`
 	Status     PipelineStatus `gorm:"column:Status; not null;"`
 	// TODO(gkcalat): this is deprecated. Consider removing and adding data migration logic at the server startup.
 	DefaultVersionId string `gorm:"column:DefaultVersionId;"` // deprecated

backend/src/apiserver/model/pipeline_spec.go

@@ -28,20 +28,21 @@ type PipelineSpec struct {
 
 	// Pipeline YAML definition. This is the pipeline interface for creating a pipeline.
 	// Stored as longtext to support large manifests (up to 4GB in MySQL).
+	// Stored as text in PostgreSQL.
 	// https://dev.mysql.com/doc/refman/8.0/en/blob.html
 	// TODO(kaikaila): consider enforcing a soft limit if needed for performance.
-	PipelineSpecManifest string `gorm:"column:PipelineSpecManifest; type:longtext;"`
+	PipelineSpecManifest LargeText `gorm:"column:PipelineSpecManifest;"`
 
 	// Argo workflow YAML definition. This is the Argo Spec converted from Pipeline YAML.
 	// This is deprecated. Use the pipeline ID, pipeline version ID, or pipeline spec manifest.
-	WorkflowSpecManifest string `gorm:"column:WorkflowSpecManifest; type:longtext;"`
+	WorkflowSpecManifest LargeText `gorm:"column:WorkflowSpecManifest;"`
 
 	// Store parameters key-value pairs as serialized string.
 	// This field is only used for V1 API. For V2, use the `Parameters` field in RuntimeConfig.
 	// At most one of the fields `Parameters` and `RuntimeConfig` can be non-empty
 	// This string stores an array of map[string]value. For example:
 	//  {"param1": Value1} will be stored as [{"name": "param1", "value":"value1"}].
-	Parameters string `gorm:"column:Parameters; type:longtext;"`
+	Parameters LargeText `gorm:"column:Parameters;"`
 
 	// Runtime config of the pipeline, only used for v2 template in API v1beta1 API.
 	RuntimeConfig

backend/src/apiserver/model/pipeline_version.go

@@ -37,7 +37,7 @@ type PipelineVersion struct {
 	Name        string `gorm:"column:Name; not null; type:varchar(127); uniqueIndex:idx_pipelineid_name;"`
 	DisplayName string `gorm:"column:DisplayName; not null"`
 	// TODO(gkcalat): this is deprecated. Consider removing and adding data migration logic at the server startup.
-	Parameters string `gorm:"column:Parameters; not null; type:longtext;"` // deprecated
+	Parameters LargeText `gorm:"column:Parameters; not null;"` // deprecated
 	// PipelineVersion belongs to Pipeline. If a pipeline with a specific UUID
 	// is deleted from Pipeline table, all this pipeline's versions will be
 	// deleted from PipelineVersion table.
@@ -47,10 +47,11 @@ type PipelineVersion struct {
 	Pipeline   Pipeline              `gorm:"foreignKey:PipelineId; references:UUID;constraint:pipeline_versions_PipelineId_pipelines_UUID_foreign,OnDelete:CASCADE,OnUpdate:CASCADE"` // This 'belongs to' relation replaces the legacy AddForeignKey constraint previously defined in client_manager.go
 	Status     PipelineVersionStatus `gorm:"column:Status; not null;"`
 	// Code source url links to the pipeline version's definition in repo.
-	CodeSourceUrl   string `gorm:"column:CodeSourceUrl;"`
-	Description     string `gorm:"column:Description; type:longtext;"`
-	PipelineSpec    string `gorm:"column:PipelineSpec; not null; type:longtext;"`    // Same as common.MaxFileLength (32MB in server). Argo imposes 700kB limit
-	PipelineSpecURI string `gorm:"column:PipelineSpecURI; not null; type:longtext;"` // Can store references to ObjectStore files
+	// nolint:staticcheck // [ST1003] Field name matches upstream legacy naming
+	CodeSourceUrl   string    `gorm:"column:CodeSourceUrl;"`
+	Description     LargeText `gorm:"column:Description;"`
+	PipelineSpec    LargeText `gorm:"column:PipelineSpec; not null;"`    // Same as common.MaxFileLength (32MB in server). Argo imposes 700kB limit
+	PipelineSpecURI LargeText `gorm:"column:PipelineSpecURI; not null;"` // Can store references to ObjectStore files
 }
 
 func (p PipelineVersion) GetValueOfPrimaryKey() string {

backend/src/apiserver/model/resource_reference.go

@@ -168,7 +168,7 @@ type ResourceReference struct {
 	Relationship Relationship `gorm:"column:Relationship; not null;"`
 
 	// JSON-encoded metadata blob about the reference
-	Payload string `gorm:"column:Payload; not null; type: longtext"`
+	Payload LargeText `gorm:"column:Payload; not null;"`
 }
 
 type ReferenceKey struct {

backend/src/apiserver/model/run.go

@@ -317,12 +317,12 @@ type RunDetails struct {
 	// For details on type lengths and index safety, refer to comments in the Pipeline struct.
 	Conditions         string           `gorm:"column:Conditions; type:varchar(125); not null;  index:experimentuuid_conditions_finishedatinsec,priority:2;index:namespace_conditions_finishedatinsec,priority:2"`
 	State              RuntimeState     `gorm:"column:State; default:null;"`
-	StateHistoryString string           `gorm:"column:StateHistory; default:null; type: longtext;"`
+	StateHistoryString LargeText        `gorm:"column:StateHistory; default:null;"`
 	StateHistory       []*RuntimeStatus `gorm:"-;"`
 	// Serialized runtime details of a run in v2beta1
-	PipelineRuntimeManifest string `gorm:"column:PipelineRuntimeManifest; not null; type:longtext;"`
+	PipelineRuntimeManifest LargeText `gorm:"column:PipelineRuntimeManifest; not null;"`
 	// Serialized Argo CRD in v1beta1
-	WorkflowRuntimeManifest string `gorm:"column:WorkflowRuntimeManifest; not null; type:longtext;"`
+	WorkflowRuntimeManifest LargeText `gorm:"column:WorkflowRuntimeManifest; not null;"`
 	// nolint:staticcheck // [ST1003] Field name matches upstream legacy naming
 	PipelineContextId int64 `gorm:"column:PipelineContextId; default:0;"`
 	// nolint:staticcheck // [ST1003] Field name matches upstream legacy naming
@@ -333,12 +333,12 @@ type RunDetails struct {
 }
 
 type RunMetric struct {
-	RunUUID     string  `gorm:"column:RunUUID; not null; primaryKey; type:varchar(191);"`
-	NodeID      string  `gorm:"column:NodeID; not null; primaryKey; type:varchar(191);"`
-	Name        string  `gorm:"column:Name; not null; primaryKey; type:varchar(191);"`
-	NumberValue float64 `gorm:"column:NumberValue;"`
-	Format      string  `gorm:"column:Format;"`
-	Payload     string  `gorm:"column:Payload; not null; type:longtext;"`
+	RunUUID     string    `gorm:"column:RunUUID; not null; primaryKey; type:varchar(191);"`
+	NodeID      string    `gorm:"column:NodeID; not null; primaryKey; type:varchar(191);"`
+	Name        string    `gorm:"column:Name; not null; primaryKey; type:varchar(191);"`
+	NumberValue float64   `gorm:"column:NumberValue;"`
+	Format      string    `gorm:"column:Format;"`
+	Payload     LargeText `gorm:"column:Payload; not null;"`
 }
 
 type RuntimeStatus struct {

backend/src/apiserver/model/runtime_config.go

@@ -16,10 +16,10 @@ package model
 
 type RuntimeConfig struct {
 	// Store parameters key-value pairs as serialized string.
-	Parameters string `gorm:"column:RuntimeParameters; type:longtext;"`
+	Parameters LargeText `gorm:"column:RuntimeParameters;"`
 
 	// A path in a object store bucket which will be treated as the root
 	// output directory of the pipeline. It is used by the system to
 	// generate the paths of output artifacts. Ref:(https://www.kubeflow.org/docs/components/pipelines/pipeline-root/)
-	PipelineRoot string `gorm:"column:PipelineRoot; type:longtext;"`
+	PipelineRoot LargeText `gorm:"column:PipelineRoot;"`
 }

backend/src/apiserver/model/task.go

@@ -37,13 +37,13 @@ type Task struct {
 	Name               string           `gorm:"column:Name; default:null"`
 	ParentTaskId       string           `gorm:"column:ParentTaskUUID; default:null"`
 	State              RuntimeState     `gorm:"column:State; default:null;"`
-	StateHistoryString string           `gorm:"column:StateHistory; default:null; type:longtext;"`
-	MLMDInputs         string           `gorm:"column:MLMDInputs; default:null; type:longtext;"`
-	MLMDOutputs        string           `gorm:"column:MLMDOutputs; default:null; type:longtext;"`
-	ChildrenPodsString string           `gorm:"column:ChildrenPods; default:null; type:longtext;"`
+	StateHistoryString LargeText        `gorm:"column:StateHistory; default:null;"`
+	MLMDInputs         LargeText        `gorm:"column:MLMDInputs; default:null;"`
+	MLMDOutputs        LargeText        `gorm:"column:MLMDOutputs; default:null;"`
+	ChildrenPodsString LargeText        `gorm:"column:ChildrenPods; default:null;"`
 	StateHistory       []*RuntimeStatus `gorm:"-;"`
 	ChildrenPods       []string         `gorm:"-;"`
-	Payload            string           `gorm:"column:Payload; default:null; type:longtext;"`
+	Payload            LargeText        `gorm:"column:Payload; default:null;"`
 }
 
 func (t Task) ToString() string {