The Workflows
experimental function,
experimental.executions.map, starts a workflow execution for each
corresponding argument, and waits for all of the executions to finish, returning
a list where each element is the result of an execution.
If you are using experimental.executions.map to support parallel work, you can
migrate your workflow to use parallel steps instead, executing ordinary
for loops in parallel.
A parallel step defines a part of your workflow where two or more steps can
execute concurrently. A parallel step waits until all the steps defined within
it have completed or are interrupted by an unhandled exception; execution then
continues. Like
experimental.executions.map, the execution order is not guaranteed. For
details, see the syntax reference page for
parallel steps.
Note that the use of experimental.executions.map or workflows.executions.run
requires additional concurrent executions quota.
However, when using parallel steps with calls to connectors
inlined (see the translation connector example), no
additional execution quota is required.
The following examples are intended to assist you when replacing the use of
experimental.executions.map with a parallel step.
Translation workflow
Given a source and target language, the following workflow, named translate,
uses the
Cloud Translation connector
to translate some input text and return the result. Note that the Cloud Translation API
must be enabled.
YAML
main:
params: [args]
steps:
- basic_translate:
call: googleapis.translate.v2.translations.translate
args:
body:
q: ${args.text}
target: ${args.target}
format: "text"
source: ${args.source}
result: r
- return_step:
return: ${r}
JSON
{
"main": {
"params": [
"args"
],
"steps": [
{
"basic_translate": {
"call": "googleapis.translate.v2.translations.translate",
"args": {
"body": {
"q": "${args.text}",
"target": "${args.target}",
"format": "text",
"source": "${args.source}"
}
},
"result": "r"
}
},
{
"return_step": {
"return": "${r}"
}
}
]
}
}
Input for the preceding example:
{
"text": "Bonjour",
"target": "en",
"source": "fr"
}
The output should resemble the following:
{
"data": {
"translations": [
{
"translatedText": "Hello"
}
]
}
}
Batch translation workflow using experimental.executions.map
The following workflow translates a batch of texts. For each input,
experimental.executions.map executes the translate workflow created
previously.
YAML
main:
steps:
- init:
assign:
- workflow_id: "translate"
- texts_to_translate:
- text: "hello world!"
source: "en"
target: "fr"
- text: "你好 世界！"
source: "zh-CN"
target: "en"
- text: "No hablo español!"
source: "es"
target: "en"
- translate_texts:
call: experimental.executions.map
args:
workflow_id: ${workflow_id}
arguments: ${texts_to_translate}
result: translated
- return:
return: ${translated}
JSON
{
"main": {
"steps": [
{
"init": {
"assign": [
{
"workflow_id": "translate"
},
{
"texts_to_translate": [
{
"text": "hello world!",
"source": "en",
"target": "fr"
},
{
"text": "你好 世界！",
"source": "zh-CN",
"target": "en"
},
{
"text": "No hablo español!",
"source": "es",
"target": "en"
}
]
}
]
}
},
{
"translate_texts": {
"call": "experimental.executions.map",
"args": {
"workflow_id": "${workflow_id}",
"arguments": "${texts_to_translate}"
},
"result": "translated"
}
},
{
"return": {
"return": "${translated}"
}
}
]
}
}
The output should resemble the following:
[
{
"data": {
"translations": [
{
"translatedText": "Bonjour le monde!"
}
]
}
},
{
"data": {
"translations": [
{
"translatedText": "Hello world!"
}
]
}
},
{
"data": {
"translations": [
{
"translatedText": "I don't speak Spanish!"
}
]
}
}
]
Replace experimental.executions.map with a for:in loop
Instead of using the experimental function, you can use a parallel for:in loop
to translate the text. In the following example, the secondary workflow,
translate, can be used as is and the output should remain unchanged. You also
have the option of starting other secondary workflow executions in
parallel branches.
A shared variable,
translated, is used to store the results and is populated with empty strings
to enable static array indexing. If ordering is not required, you can use
list.concat to append the
results. All assignments in parallel steps are atomic.
YAML
JSON
Replace experimental.executions.map with a for:range loop
Instead of using the experimental function, you can use a parallel for:range
loop to translate the text. By using a for:range loop, you can specify
the beginning and end of an iteration range. The output should remain unchanged.
YAML
JSON
Inline the workflow source code
If the secondary workflow is relatively brief, you might want to include it
directly within the main workflow for easier readability. For example, in the
following workflow, the source code for the translate workflow has been
inlined.