@sap/cds-compiler/lib/base/trace.js

CDS (Core Data Services) compiler and backends

'use strict';

const shouldTraceApi = process?.env?.CDSC_TRACE_API;

/**
 * Placeholder for disabled tracing (no-op).
 */
function noOp() {
  // no-op
}

/**
 * Print trace info to stderr when calling an API function
 */
function call( apiName, options, csn, files ) {
  const { version } = require('../../package.json');
  const now = (new Date( Date.now() )).toISOString();
  const args = (files || csn)
    ? `${ optionsString( options ) } on ${ filesInfo( files ) || csnInfo( csn ) }`
    : optionsString( options );
  // eslint-disable-next-line no-console
  console.error( 'CDSC_TRACE_API: at %s, call %s() of v%s with options %s',
                 now, apiName, version, args );
}

/**
 * Print trace info to stderr when exiting an API function
 */
function exit( apiName, result ) {
  const now = (new Date( Date.now() )).toISOString();
  const info = (result?.definitions || result?.extensions)
    ? csnInfo( result )
    : `a result of type ${ typeof result }`;
  // eslint-disable-next-line no-console
  console.error( 'CDSC_TRACE_API: at %s, exit %s() and return %s',
                 now, apiName, info );
}

/**
 * Print trace info to stderr for miscellaneous use cases
 */
function log( info ) {
  const now = (new Date( Date.now() )).toISOString();
  // eslint-disable-next-line no-console
  console.error( 'CDSC_TRACE_API: at %s, %s', now, info );
}

function optionsString( obj ) {
  if (!obj || typeof obj !== 'object')
    return obj.toString();
  try {
    if (Array.isArray( obj.messages ) && obj.messages.length) {
      const messages = {};
      for (const msg of obj.messages)
        messages[msg.severity] = (messages[msg.severity] || 0) + 1;
      obj = { ...obj, messages };
    }
    return JSON.stringify( obj, null, 2 );
  }
  catch (err) {
    return err.toString();
  }
}

function filesInfo( files ) {
  if (!files)
    return files;
  if (!Array.isArray( files ))
    files = Object.keys( files );
  return files.length ? [ 'files', ...files ].join( '\n  ') : 'no files';
}

function csnInfo( csn ) {
  if (!csn || typeof csn !== 'object' || Array.isArray( csn ))
    return `some value of type ${ typeof csn }`;
  try {
    JSON.stringify( csn );
    const defs = csn.definitions ? Object.keys( csn.definitions ).length : 'no';
    const exts = csn.extensions ? csn.extensions.length : 'no';
    const flavor = csn.meta?.flavor || csn.meta?.compilerCsnFlavor || 'unknown';
    return `a CSN of flavor '${ flavor }' with ${ defs } definitions and ${ exts } extensions`;
  }
  catch (err) {
    return `a CORRUPTED CSN (${ err.toString() })`;
  }
}

module.exports = (shouldTraceApi)
  ? { call, exit, log }
  : { call: noOp, exit: noOp, log: noOp };