How To Get the Code From a SAS Studio Flow and Why It Matters
SAS customers need to run a SAS Studio Flow in batch or from a CI/CD pipeline. They also need to version the flow code, possibly in a Git repository and compare the changes from one version to another. To achieve these goals, you need the SAS code behind the SAS Studio Flow. A REST API helps you generate the code. Read the post to find out more.
Why is This Important?
SAS Customers want to run SAS Studio Flows:
- In batch, from the command line.
- From a CI/CD pipeline, for example from Azure Pipelines or Jenkins.
-
From open-source programming languages, such as Python.
They also want to:
-
Version the flows in Git repositories.
-
Compare the code changes from one version to another.
The Key
To run a SAS Studio Flow in batch or in a pipeline, you need the SAS code behind the flow.
To compare two versions of the same SAS Studio Flow, you need the SAS code behind the flow.
The Answer: a REST API
To generate the SAS code, use the /studioDevelopment/code REST API. The API is also known as the "CodeGen" or the “Code Generation” API, because it “generates” the SAS code from a SAS Studio Flow file.
The studioDevelopment REST API has been available since the SAS Viya 2022.09 Long Term Support.
Practical Example
Watch the following video for an overview of the approach:
SAS Studio Flow
Suppose you developed a flow that performs a de-duplication of an existing table.
To generate the SAS code form this flow you could write a SAS program:
SAS Code Generation Program
You need to initialize several files:
- input – will be posted to the REST API endpoint. Perhaps, the most important in this JSON file is the path to your SAS Studio Flow.
- resp – has the REST API response.
- flowcode – holds the generated SAS code.
filename resp clear;
filename input clear;
filename flowcode clear;
filename input temp;
data _null_;
file input recfm=f lrecl=1;
put "{";
put """reference"": {";
put """type"": ""content"",";
put """path"": ""/Users/sasuser/My Folder/Flow.flw"",";
put """mediaType"": ""application/vnd.sas.dataflow""";
put "},";
put """initCode"": true,";
put """wrapperCode"": false";
put "}";
run;
You then POST to the studioDevelopment/code REST API the input JSON file. For Authentication, you can reuse the SAS_SERVICES token, if you are writing the program inside SAS Studio.
%let myviyaurl = %sysfunc(getoption(servicesbaseurl));
%put NOTE: &=myviyaurl;
filename resp temp;
proc http url = "&myviyaurl/studioDevelopment/code"
in=input
out= resp
method="POST"
OAUTH_BEARER=SAS_SERVICES VERBOSE;
headers
"Content-Type" = "application/json;charset=utf-8"
"Accept" = "application/json"
;
run;
libname resp clear;
libname resp json;
/* OUTPUT:
resp json
libname resp json:
ALLDATA with columns: P, P1, V, Value
ROOT with columns: ordinal_root, code
Both root.code and alldata.value = the SAS Program generated from the source FLOW */
Run Result
When you run the program and it is successful, you should see a 200 OK. It means, the REST API generated the code from the SAS Studio Flow.
You can then define a JSON library on top of the resp JSON file. From Libraries, open RESP.ROOT and notice the SAS Studio Flow code is stored in the code field.
SAS Code to a File
You can write this program to extract the code to a file called flowcode.
* Save the code in a file you want to execute:;
* The flowcode must not have references to paths unknown to the Batch service;
filename flowcode temp;
data _null_;
set resp.root;
file flowcode;
put code;
run;
quit;Save and Version the SAS Code
Alternatively, you can save the code to a SAS file, on the file system.
filename flowcode '/azuredm/gitrepo/programs/Flow.sas';
data _null_;
set resp.root;
file flowcode;
put code;
run;
quit;
You can also save it directly to a Git repository, provided you added one in SAS Studio.
Execute the SAS Code
Depending on your use case, you can execute the code, using an %include statement, effectively executing the flow code.
* Skip errors if any from the flow code;
options nosyntaxcheck;
* Execute the flow file;
%include flowcode;
quit;I also noticed that the generated code sometimes throws small errors when executed, hence the nosyntaxcheck option will help.
This is not the only way to run the SAS code. According to my colleague Alexey Vodilin, you can [use the] Compute API or Job Execution Service API depending on [your] use case. All these APIs are publicly available.
PyViyaTools
And since we are discussing Python and code generation, Gerry Nelson has just created a new pyviyatool named exportstudioflowcode.py. The nice thing about it is that it can loop through a folder and convert all the SAS Studio Flows from that folder.
# usage:
exportstudioflowcode.py [-h] -t {Flow,Folder} -n NAME -d DIRECTORY [--includeinitcode] [--includewrappercode]The pyviyatools are a set of command-line tools that call SAS Viya REST APIs from Python. These tools simplify common administration tasks, provide more complex functionality and are a great complement to the SAS Viya CLI. The tools are available on the public SAS Software GitHub.
Conclusion
The /studioDevelopment/code REST API, also known as "CodeGen" can help you generate SAS code from a SAS Studio Flow.
With the code, you can further run a SAS Studio Flow in batch or from a CI/CD pipeline. Or, you can version the flow code using Git repositories and compare the changes from one version to another.
In a next post, we will look How to Get the Code From a SAS Studio Flow Using Python.
Acknowledgements
Thank you, Alexey Vodilin, Mark Escauriaga, Patric Hamilton, Cecily Hoffritz and Bruno Mueller for helping me figure out how this SAS REST API works and suggesting code improvements.
Resources
- How to Get the Code From a SAS Studio Flow Using Python.
- pyviyatools.
- SAS.COM codeGeneration REST API.
- SAS Documentation SAS Viya 2022.09 Long Term Support.
Thank you for your time reading this post. If you liked the post, give it a thumbs up! Please comment and tell us what you think about SAS codeGen REST API. If you wish to get more information, please write me an email.
