Compute Service made easy

Introduction

In this section I discuss how to use restaflib methods to program for a typical use case of compute service. The compute service API covers many different uses. The simplest and most common use case is to run a SAS job and view the ODS output, log, listing and browse the generated tables

Methods

computeSetup

This method creates a compute service session.

Syntax

let session = await restaflib.computeSetup(store, contextName);

The parameters are:

• store - restaf store object
• contextName - (optional) If not specified the first context in the list will be used

computeRun

This method executes the specified code on the server

let computeSummary = await restaflib.computeRun(store, session, src, macros)

The parameters are:

• store - restaf store object
• session - The session object obtained thru the computeSetup method
• src - A string containing the source code to be executed.
• macros - (optional) A javascript object that is sent to the server as macros. For example if this object is {lib: 'sasuser', data: 'mydata'} the following macros are prepended to the source code

    %let lib=sasuser; 
    %let data=mydata;
  

The result from the computeRun method are used to retrieve specific results using the following methods.

computeResults

This method is used to get the ods output, log, listing and the list of tables.

Syntax

 let result = await restaflib.computeResults(store, computeSummary, type)

The parameters are:

• store - The restaf store
• computeSummary - The output from restaflib.computeRun
• type - A string with one of the following values ods|log|listing|tables. Based on this option different results are returned

The results based on the value of type are:

• ods - This will return a string that has the ODS output. This html can be passed to some component for display
• log - This will return all the log for this particular job. The content is an array of objects that follows the media type for [loglines] log lines
• listing - This will return all the listings for this particular job. This has the same format as the log
• tables - This returns an array with the names of the tables returned by the job. Use this name to retrieve the actual records using the restaflib.computeFetchData method described below

computeFetchData

Use this method to page thru the records of the tables returned by the computeRun method. This method takes advantage of the standard scrolling rels and links.

Syntax

let result = await restaflib.computeFetchData(store, computeSummary, tablename, direction);

The parameters are:

• store - restaf store
• computeSummary - the output from restaflib.computeRun
• tablename - the name of the table returned (see computeResults method above).
• direction - a string to indicate which direction to scroll and get records. If not specified the first set of records are returned. The valid values of this parameter depend on what was returned in the scrollOptions field of the result see below

The result from the computeFetchData has the following schema

{
  rows: An array of data rows - and each data row is an array of values for that row,
  columns: The standard schema for the columns
 scrollOptions: An array of strings with possible values for the next scroll. These usually are one or more of the following values: first, next, prev, last. Use this to move through the data set.
} 

Sample code

async function test_computeRun () {
let computeSession = await computeSetup(store);
/* prep input */
let macros = {maxRows: 500};
let src =  ods html style=barrettsblue; data work.dtemp1; array x{10};   do j = 1 to &maxRows;   do i = 1 to 10;   x{i} = i * 10;   end;   output;   put _ALL_;   end;   run;   proc print;run;   ods html close;;
// Run the SAS job
let computeSummary = await restaflib.computeRun(store, computeSession, src,  macros);
// Get log, listing, ods and list of tables
let log = await restaflib.computeResults(store, computeSummary, 'log');
let list = await restaflib.computeResults(store, computeSummary, 'listing');
let ods = await restaflib.computeResults(store, computeSummary, 'ods');
let tables = await restaflib.computeResults(store, computeSummary, 'tables');
// Scroll thru one of the tables
let data = await restaflib.computeFetchData(store,computeSummary, 'DTEMP1');
console.log(data.columns);
console.log(First row in set: ${data.rows[0]});
console.log(Last row in set: ${data.rows[data.rows.length-1]});
console.log(Pagination links: ${data.scrollOptions});
console.log('\n');
do {
data = await restaflib.computeFetchData(store,computeSummary, 'DTEMP1', 'next');
if (data !== null) {
// print.object(computeSummary.tables['DTEMP1'].current.raw('data', 'results','links'), 'pagination links');
console.log(First row in set: ${data.rows[0]});
console.log(Last row in set: ${data.rows[data.rows.length-1]});
console.log(Pagination links: ${data.scrollOptions});
console.log('\n');
}
} while (data != null);
// Now scroll backwards to the top
do {
data = await restaflib.computeFetchData(store,computeSummary, 'DTEMP1', 'prev');
if (data !== null) {
console.log(data.rows[0]);
console.log(JSON.stringify(data.scrollOptions, null,4));
}
} while (data != null);
// Delete session
await store.apiCall(computeSession.links('delete'));
}

Notes

The methods discussed in this blog relies on the restaf library. If you want to do more complicated operations with compute service using restaf please see the documentation on restaf.

Setup

Web Applications

Include the following two script tags.

    <script src="https://unpkg.com/@sassoftware/restaf/dist/restaf.min.js"></script>

    <script src="https://unpkg.com/@sassoftware/restaflib/dist/restaflib.min.js"></script>

Two globals restaf and restaflib will be available for use in your script tags.

Nodejs application

Install restaf and restaflib using the following command

    npm install @sassoftware/restaf @sassoftware/restaflib