Question: Does the Dify platform (which version) support the feature of nesting iterative nodes within iterative nodes during the orchestration process
I’ve encountered a similar requirement before—within the same flow, neither iteration nor loops can nest another iteration. At that time, my approach was to extract the inner iteration into a sub-flow (creating a new workflow and publishing it as a tool).
Hope this helps.
Thank you for your response. I also tried your method, but calling the workflow-published tool within an iteration results in an error, and I haven’t yet found a solution.
Dify version: v1.4.1
Error message:
{“event”: “error”, “conversation_id”: “fc5c8beb-7b1b-481f-a3ee-1f0157250820”, “message_id”: “7e74f498-dffb-4f5a-ab52-6440cdff222c”, “created_at”: 1764059934, “code”: “invalid_param”, “status”: 400, “message”: “Run failed: ‘AnonymousUserMixin’ object has no attribute ‘session_id’”}
I tried it on the cloud version, and it works.
Two apps:
app:
description: ''
icon: 🤖
icon_background: '#FFEAD5'
mode: advanced-chat
name: Outer iteration
use_icon_as_answer_icon: false
dependencies: []
kind: app
version: 0.5.0
workflow:
conversation_variables: []
environment_variables: []
features:
file_upload:
allowed_file_extensions:
- .JPG
- .JPEG
- .PNG
- .GIF
- .WEBP
- .SVG
allowed_file_types:
- image
allowed_file_upload_methods:
- local_file
- remote_url
enabled: false
fileUploadConfig:
audio_file_size_limit: 50
batch_count_limit: 5
file_size_limit: 15
image_file_batch_limit: 10
image_file_size_limit: 10
single_chunk_attachment_limit: 10
video_file_size_limit: 100
workflow_file_upload_limit: 10
image:
enabled: false
number_limits: 3
transfer_methods:
- local_file
- remote_url
number_limits: 3
opening_statement: ''
retriever_resource:
enabled: true
sensitive_word_avoidance:
enabled: false
speech_to_text:
enabled: false
suggested_questions: []
suggested_questions_after_answer:
enabled: false
text_to_speech:
enabled: false
language: ''
voice: ''
graph:
edges:
- data:
isInIteration: false
isInLoop: false
sourceType: start
targetType: code
id: 1767664259503-source-1767664274225-target
source: '1767664259503'
sourceHandle: source
target: '1767664274225'
targetHandle: target
type: custom
zIndex: 0
- data:
isInIteration: false
isInLoop: false
sourceType: code
targetType: iteration
id: 1767664274225-source-1767664632458-target
source: '1767664274225'
sourceHandle: source
target: '1767664632458'
targetHandle: target
type: custom
zIndex: 0
- data:
isInIteration: true
isInLoop: false
iteration_id: '1767664632458'
sourceType: iteration-start
targetType: tool
id: 1767664632458start-source-1767664645351-target
source: 1767664632458start
sourceHandle: source
target: '1767664645351'
targetHandle: target
type: custom
zIndex: 1002
- data:
isInIteration: false
isInLoop: false
sourceType: iteration
targetType: answer
id: 1767664632458-source-1767664662774-target
source: '1767664632458'
sourceHandle: source
target: '1767664662774'
targetHandle: target
type: custom
zIndex: 0
nodes:
- data:
selected: false
title: User Input
type: start
variables: []
height: 73
id: '1767664259503'
position:
x: 0
y: 49
positionAbsolute:
x: 0
y: 49
selected: false
sourcePosition: right
targetPosition: left
type: custom
width: 242
- data:
code: "function main({query}) {\n return {\n result: query.split('').filter(it\\\n => !!it.trim())\n }\n}\n"
code_language: javascript
outputs:
result:
children: null
type: array[string]
selected: false
title: Code
type: code
variables:
- value_selector:
- sys
- query
value_type: string
variable: query
height: 52
id: '1767664274225'
position:
x: 342
y: 60
positionAbsolute:
x: 342
y: 60
selected: false
sourcePosition: right
targetPosition: left
type: custom
width: 242
- data:
error_handle_mode: terminated
flatten_output: true
height: 172
is_parallel: true
iterator_input_type: array[string]
iterator_selector:
- '1767664274225'
- result
output_selector:
- '1767664645351'
- output
output_type: array[string]
parallel_nums: 10
selected: false
start_node_id: 1767664632458start
title: Iteration
type: iteration
width: 620
height: 172
id: '1767664632458'
position:
x: 684
y: 0
positionAbsolute:
x: 684
y: 0
selected: true
sourcePosition: right
targetPosition: left
type: custom
width: 620
zIndex: 1
- data:
desc: ''
isInIteration: true
selected: false
title: ''
type: iteration-start
draggable: false
height: 48
id: 1767664632458start
parentId: '1767664632458'
position:
x: 60
y: 62
positionAbsolute:
x: 744
y: 62
selectable: false
sourcePosition: right
targetPosition: left
type: custom-iteration-start
width: 44
zIndex: 1002
- data:
isInIteration: true
isInLoop: false
is_team_authorization: true
iteration_id: '1767664632458'
paramSchemas:
- auto_generate: null
default: ''
form: llm
human_description:
en_US: ''
ja_JP: ''
pt_BR: ''
zh_Hans: ''
label:
en_US: text
ja_JP: text
pt_BR: text
zh_Hans: text
llm_description: ''
max: null
min: null
name: text
options: []
placeholder:
en_US: ''
ja_JP: ''
pt_BR: ''
zh_Hans: ''
precision: null
required: true
scope: null
template: null
type: string
params:
text: ''
plugin_id: null
plugin_unique_identifier: null
provider_icon:
background: '#FFEAD5'
content: 🤖
provider_id: a8faebfb-0feb-4063-96d4-78de859d17c5
provider_name: Inner iteration
provider_type: workflow
selected: false
title: Inner iteration
tool_configurations: {}
tool_description: ''
tool_label: Inner iteration
tool_name: repeat_and_concat_emoji
tool_node_version: '2'
tool_parameters:
text:
type: mixed
value: '{{#1767664632458.item#}}'
type: tool
height: 52
id: '1767664645351'
parentId: '1767664632458'
position:
x: 184
y: 60
positionAbsolute:
x: 868
y: 60
selected: false
sourcePosition: right
targetPosition: left
type: custom
width: 242
zIndex: 1002
- data:
answer: '{{#1767664632458.output#}}'
selected: false
title: Answer
type: answer
variables: []
height: 103
id: '1767664662774'
position:
x: 1404
y: 34
positionAbsolute:
x: 1404
y: 34
selected: false
sourcePosition: right
targetPosition: left
type: custom
width: 242
viewport:
x: 185.71703578532265
y: 301.09544880644967
zoom: 0.5638670037341258
rag_pipeline_variables: []
And
app:
description: ''
icon: 🤖
icon_background: '#FFEAD5'
mode: workflow
name: Inner iteration
use_icon_as_answer_icon: false
dependencies: []
kind: app
version: 0.5.0
workflow:
conversation_variables: []
environment_variables: []
features:
file_upload:
allowed_file_extensions:
- .JPG
- .JPEG
- .PNG
- .GIF
- .WEBP
- .SVG
allowed_file_types:
- image
allowed_file_upload_methods:
- local_file
- remote_url
enabled: false
fileUploadConfig:
audio_file_size_limit: 50
batch_count_limit: 5
file_size_limit: 15
image_file_batch_limit: 10
image_file_size_limit: 10
single_chunk_attachment_limit: 10
video_file_size_limit: 100
workflow_file_upload_limit: 10
image:
enabled: false
number_limits: 3
transfer_methods:
- local_file
- remote_url
number_limits: 3
opening_statement: ''
retriever_resource:
enabled: true
sensitive_word_avoidance:
enabled: false
speech_to_text:
enabled: false
suggested_questions: []
suggested_questions_after_answer:
enabled: false
text_to_speech:
enabled: false
language: ''
voice: ''
graph:
edges:
- data:
isInIteration: false
isInLoop: false
sourceType: start
targetType: code
id: 1767664421409-source-1767664444690-target
source: '1767664421409'
sourceHandle: source
target: '1767664444690'
targetHandle: target
type: custom
zIndex: 0
- data:
isInIteration: false
isInLoop: false
sourceType: code
targetType: iteration
id: 1767664444690-source-1767664515327-target
source: '1767664444690'
sourceHandle: source
target: '1767664515327'
targetHandle: target
type: custom
zIndex: 0
- data:
isInIteration: true
isInLoop: false
iteration_id: '1767664515327'
sourceType: iteration-start
targetType: code
id: 1767664515327start-source-1767664525741-target
source: 1767664515327start
sourceHandle: source
target: '1767664525741'
targetHandle: target
type: custom
zIndex: 1002
- data:
isInIteration: false
isInLoop: false
sourceType: iteration
targetType: end
id: 1767664515327-source-1767664551992-target
source: '1767664515327'
sourceHandle: source
target: '1767664551992'
targetHandle: target
type: custom
zIndex: 0
nodes:
- data:
selected: false
title: User Input
type: start
variables:
- default: ''
hint: ''
label: text
max_length: 48
options: []
placeholder: ''
required: true
type: paragraph
variable: text
height: 109
id: '1767664421409'
position:
x: 0
y: 146
positionAbsolute:
x: 0
y: 146
selected: false
sourcePosition: right
targetPosition: left
type: custom
width: 242
- data:
code: "def main(text: str) -> dict:\n \"\"\" \n 将输入的字符串重复 3 次，并将其拆分为单个字符的列表。 \n \n 参数: \n text (str): 输入的字符串。 \n \n 返回: \n \n dict: 包含结果列表的字典。 \n \"\"\" \n # 1. text * 3 对应 JS 的 text.repeat(3) \n # 2. list(...) 对应 JS 的 .split(\"\")，将字符串转换为字符列表 \n return {\n \n \"result\": list(text * 3)\n }"
code_language: python3
outputs:
result:
children: null
type: array[string]
selected: false
title: Code
type: code
variables:
- value_selector:
- '1767664421409'
- text
value_type: string
variable: text
height: 52
id: '1767664444690'
position:
x: 342
y: 175
positionAbsolute:
x: 342
y: 175
selected: false
sourcePosition: right
targetPosition: left
type: custom
width: 242
- data:
error_handle_mode: terminated
flatten_output: true
height: 402
is_parallel: false
iterator_input_type: array[string]
iterator_selector:
- '1767664444690'
- result
output_selector:
- '1767664525741'
- result
output_type: array[string]
parallel_nums: 10
selected: false
start_node_id: 1767664515327start
title: Iteration
type: iteration
width: 547
height: 402
id: '1767664515327'
position:
x: 684
y: 0
positionAbsolute:
x: 684
y: 0
selected: false
sourcePosition: right
targetPosition: left
type: custom
width: 547
zIndex: 1
- data:
desc: ''
isInIteration: true
selected: false
title: ''
type: iteration-start
draggable: false
height: 48
id: 1767664515327start
parentId: '1767664515327'
position:
x: 60
y: 62
positionAbsolute:
x: 744
y: 62
selectable: false
sourcePosition: right
targetPosition: left
type: custom-iteration-start
width: 44
zIndex: 1002
- data:
code: "\ndef main(item: str):\n return {\n \"result\": f\"{item} \\U0001F60A\"\n }\n"
code_language: python3
isInIteration: true
isInLoop: false
iteration_id: '1767664515327'
outputs:
result:
children: null
type: string
selected: false
title: Code 2
type: code
variables:
- value_selector:
- '1767664515327'
- item
value_type: string
variable: item
height: 52
id: '1767664525741'
parentId: '1767664515327'
position:
x: 184
y: 60
positionAbsolute:
x: 868
y: 60
selected: true
sourcePosition: right
targetPosition: left
type: custom
width: 242
zIndex: 1002
- data:
outputs:
- value_selector:
- '1767664515327'
- output
value_type: array[string]
variable: output
selected: false
title: Output
type: end
height: 88
id: '1767664551992'
position:
x: 1331
y: 157
positionAbsolute:
x: 1331
y: 157
sourcePosition: right
targetPosition: left
type: custom
width: 242
viewport:
x: 0
y: 0
zoom: 0.7
rag_pipeline_variables: []
I forgot to mention one thing when replying this morning 
, in Dify, previewing works fine as you said, but when calling Dify via API from the frontend, an error occurs.
Are you referring to the method of calling through the Service API? I tried it here and it worked fine.
Judging from your error message, it seems there might be an issue with the User during the call.
It was called through the Service API method, and we also considered it might be a User issue, but haven’t found a solution yet.