run web server:
./app.py
To learn better run
python tests/test_simple.py
- in the first step you should define a workflow to server to define new workflow call below address using standard HTTP call:
http POST http://server_address/wf/{workflow name:string}/{workflow version:number}
- content must be a json which defines our workflow. for example:
http POST http://server_address/wf/my_test_workflow/1
- json which sends to server must have below schema:
{
"name" : "workflow name",
"steps":[
{type= "taskcall", taskname="taskname to call in this step", params = [parameters to pass to task]}
...
or
{
type="eval",
params = [ ''' string to evaluate ''']
}
...
http POST http://server_address/wf/my_test_workflow/1
{
"name":"my_test_workflow",
"steps":[
{
"type":"taskcall",
"taskname":"test_task_add_two_number",
"params":[12,13,"c"]
}
]
}
this sample defines a simple workflow that add two number. test_task_add_two_number is a task which defined in our workflow server as below:
def test_task_add_two_number(a,b,
result_var_name):
def l(obj,eng):
obj[result_var_name]=a+b
return l
as you see, our function has 3 parameter that pass to it using params section of task call in our json. all tasks must defined to our workflow server
To run this workflow :
POST http://server_address/run/{workflow name}/{workflow version}/{customer id}
And Body:
json that initialize workflow variables
customer id is an identifcation number which specifies this wf(workflow) instance
in the case of VAS service it is user mobile number that this wf runs for. to run pervious workflow:
http POST http://server_address/run/my_test_workflow/1/242233
Content-Type: application/json
To get variables from workflow after its run we should defines which variables we need, see below:
http POST http://server_address/run/my_test_workflow/1/123232
{
"__rtn_vars__":["c"]
}
above says to workflow engine (WE) runs my_test_workflow for customer id 123232 and returns variable c. as you know c must be 25 (12+13)
to improve our understanding see this example:
{
"name":"simple_login"
"steps":[
{
"taskname":"IF_ELSE",
"type":"taskcall",
"params":[
{
"type":"eval",
"params":[
" lambda obj,eng: obj['username']=='gholi' and obj['password']=='gholi' "
]
},
{
"taskname":"task_exec",
"type":"taskcall"
"params":[
"
def l(obj,eng):
obj['rtn']= 'hello dear '+obj['username']
obj['user_login']=True
",
"l"
],
},
{
"taskname":"task_exec",
"type":"taskcall"
"params":[
"
def l(obj,eng):
obj['rtn']='failed to Login'\n obj['user_login']=False
",
"l"
],
}
],
}
],
}
Explanation:
-
this example created by 1 task, it is
IF_ELSEtask,IF_ELSEtask has 3 arguments -
first is condition which is a lambda expression to determine
TrueofFalse. -
second parameter is list of tasks if condition was
True. -
Thrid parameter is list of tasks if condition was
False. -
As you see first parameter of
IF_ELSEtask is:
{
"type":"eval",
"params":[
" lambda obj,eng: obj['username']=='gholi' and obj['password']=='gholi' "
]
}
which defines an eval task that compiles to :
lambda obj,eng: obj['username']=='gholi' and obj['password']=='gholi'
that compare username and password to gholi
and if both of them are gholi returns True else returns False.
- the second parameter is (True Branch of IF_ELSE [can be list of tasks]):
{
"taskname":"task_exec",
"type":"taskcall",
"params":[
'''
def l(obj,eng):
obj['rtn']= 'hello dear '
+obj['username']
obj['user_login']=True
''',
"l"
],
}
it is a task_exec which exec string in server, task_exec has two parameters:
task_exec(code_string,function_name_string)
code_string can be full Python Module but at final should define a function that has two parameter (obj,eng) that returns from it.
as you see this Task sets rtn variable of WF to "hello dear {username}" and
sets user_login variable to True
to run this WF we call run method using:
POST http://server_address/wf/run/simple_login/1/12344
{
'__rtn_vars__':['rtn','user_login'],
'username':'gholi',
'password':'jafar'
}
above call sets username and password variable of workflow to 'gholi' and 'jafar' and says to workflow returns rtn,user_login variables from workflow.
Sometimes we need call external web-api and interact with them to do this we do below steps: 1. define web url and its type to server using below call:
POST http://server_address/wf/define/task
{
"task_name":"task name which use in WF to specifies this web task",
"task_type":"can be sync or async"
"url":"url of server method"
}
sync tasks wait to get response from server and workflow waits for the result async tasks halts workflow and wait to call from web server to callbacked
for example:
POST http://server_address/wf/define/task
{
"task_name":"reg_user",
"task_type":"sync",
"url":"http://127.0.0.1:8282/mockservice/user"
}
2. To use in our wf we should define a task as below:
{
"type":"taskcall",
"taskname":"task_dynamic_task",
params=[
"web task name",
"prefix of return result",
{
web_call_param1:{type='var or value',var_name='variable name' or value = "direct value"},
....
}]
}
For example:
{
type='taskcall',
taskname='task_dynamic_task',
params=[
'reg_user',
'ru',
{
username:{type:'var',var_name:'username'},
password:{type:'var',var_name:'password'},
req_date:{type:'value',value:13931413},
from_service_name:{type:'value',value:'simple test to farsheed!'}
}
]
}
in this sample WF calls reg_user web task which defined before and add ru prefix in the head of its returns json
for example if this web call returns json as below:
{userid:12,status:'ok'}
the wf add re as prefix to them and add them to wf variables, re_userid=12 and re_status='ok' added to wf variables
last parameter is a dictionary which pass as parameter to web call
username variable from workflow pass to web call as username in json body
password variable from wf pass to web-call as password in json body
req_date as direct value 13931413 pass to web-call as req_date and so on.