refactor input/output and commands

cmd/flamegraph

@@ -5,24 +5,16 @@
  */
 
 var mod_bunyan = require('bunyan');
-
-var mod_input_common = require('../lib/input-common');
-var mod_input_collapsed = require('../lib/input-collapsed');
-var mod_output_flamegraph = require('../lib/output-flamegraph-svg');
+var mod_stackvis = require('../lib/stackvis');
 
 var log = new mod_bunyan({
     'name': 'flamegraph',
     'stream': process.stderr
 });
 
-var reader = new mod_input_collapsed.reader(process.stdin, log);
-
-mod_input_common.collapseStacks(reader, function (err, stacks) {
-	mod_output_flamegraph.emit({
-	    'stacks': stacks,
-	    'output': process.stdout,
-	    'log': log
-	}, function () {});
-});
+var reader = new mod_stackvis.readerLookup('collapsed');
+var writer = new mod_stackvis.writerLookup('flamegraph-svg');
 
+mod_stackvis.pipeStacks(log, process.stdin, reader, writer, process.stdout,
+    function () {});
 process.stdin.resume();

cmd/stackcollapse

@@ -4,20 +4,17 @@
  * cmd/stackcollapse: emit collapsed stack traces from DTrace output
  */
 
-var mod_input_common = require('../lib/input-common');
-var mod_input_dtrace = require('../lib/input-dtrace');
 var mod_bunyan = require('bunyan');
+var mod_stackvis = require('../lib/stackvis');
 
 var log = new mod_bunyan({
     'name': 'stackcollapse',
     'stream': process.stderr
 });
 
-var reader = new mod_input_dtrace.reader(process.stdin, log);
-mod_input_common.collapseStacks(reader, function (err, stacks) {
-	stacks.eachStackByCount(function (frames, count) {
-		process.stdout.write(frames.join(',') + ' ' + count + '\n');
-	});
-});
+var reader = mod_stackvis.readerLookup('dtrace');
+var writer = mod_stackvis.writerLookup('collapsed');
 
+mod_stackvis.pipeStacks(log, process.stdin, reader, writer, process.stdout,
+    function () {});
 process.stdin.resume();

lib/output-collapsed.js

@@ -0,0 +1,27 @@
+/*
+ * lib/output-collapsed.js: emits StackSets in collapsed format, compatible with
+ * Brendan Gregg's FlameGraph tool.
+ */
+
+var mod_assert = require('assert');
+
+/*
+ * Arguments:
+ *
+ *    stacks	StackSet		Stacks to visualize
+ *
+ *    output	WritableStream		Output file
+ */
+exports.emit = function emitCollapsed(args, callback)
+{
+	mod_assert.ok(args.stacks && args.stacks.constructor &&
+	    args.stacks.constructor.name == 'StackSet',
+	    'required "stacks" argument must be a StackSet');
+	mod_assert.ok(args.output && args.output.write &&
+	    typeof (args.output.write) == 'function',
+	    'required "output" argument must be a function');
+
+	args.stacks.eachStackByCount(function (frames, count) {
+		process.stdout.write(frames.join(',') + ' ' + count + '\n');
+	});
+};

lib/input-common.js → lib/stackvis.js

@@ -1,9 +1,29 @@
 /*
- * lib/input-common.js: common routines for importing stacks
+ * lib/stackvis.js: Stackvis library interface
  */
 
 var mod_assert = require('assert');
 
+exports.readerLookup = readerLookup;
+exports.writerLookup = writerLookup;
+exports.pipeStacks = pipeStacks;
+
+function moduleLookup(type, name)
+{
+	var filename = './' + type + '-' + name;
+	return (require(filename));
+}
+
+function readerLookup(name)
+{
+	return (moduleLookup('input', name).reader);
+}
+
+function writerLookup(name)
+{
+	return (moduleLookup('output', name));
+}
+
 function StackSet()
 {
 	this.ss_counts = {};	/* maps serialized stack -> count */
@@ -49,7 +69,7 @@ StackSet.prototype.eachStackByStack = function (callback)
 	});
 };
 
-exports.collapseStacks = function (reader, callback)
+function collapseStacks(reader, callback)
 {
 	var stacks = new StackSet();
 
@@ -58,4 +78,27 @@ exports.collapseStacks = function (reader, callback)
 	});
 
 	reader.on('end', function () { callback(null, stacks); });
-};
+}
+
+/*
+ * This is *not* a stable interface yet. This will be changed in the future to
+ * support multiple stage pipelines.
+ */
+/* XXX use args for argument. */
+function pipeStacks(log, instream, readercons, writer, outstream, callback)
+{
+	var reader = new readercons(instream, log);
+
+	collapseStacks(reader, function (err, stacks) {
+		if (err) {
+			log.error(err);
+			return;
+		}
+
+		writer.emit({
+			'stacks': stacks,
+			'output': outstream,
+			'log': log
+		}, callback);
+	});
+}