finished aggregate file example

examples/aggregatedFileExample.cpp

@@ -16,6 +16,13 @@ telemetry::Content returnValue(int value) {
     return telemetry::Scalar(value);
 }
 
+telemetry::Content returnValueDict(int value) {
+    telemetry::Dict dict;
+    dict["1"] = telemetry::Scalar(value*2);
+
+    return dict;
+}
+
 int main() {
     // Same as basic example
     std::shared_ptr<telemetry::Directory> telemetryRootNode;
@@ -26,31 +33,74 @@ int main() {
     telemetry::appFs::AppFsFuse fuse = telemetry::appFs::AppFsFuse(telemetryRootNode, fusePath, true, true);
 	fuse.start();
 
+    // We create two fileops that just return a constant value
     const telemetry::FileOps fileOps1
         = {[]() { return returnValue(2); }, nullptr};
 
     const telemetry::FileOps fileOps2
         = {[]() { return returnValue(5); }, nullptr};
 
+
+    // It is better to keep the files in another directory and not 
+    // aggregate them straight from root dir.
     auto aggFileDir = telemetryRootNode->addDir("aggDir");
     auto file1 = aggFileDir->addFile("file1", fileOps1);
     auto file2 = aggFileDir->addFile("file2", fileOps2);
 
-    const telemetry::AggOperation aggOp  = {telemetry::AggMethodType::JOIN, "", "1"};
+    // Here we init three different aggregation operations.
+    // One of them is join meaning it will add values from all files into an array.
+    // The two arguments after the method type are source dict field name and result dict field name
+    // If they are left empty ("") the values are taken directly from file->read() and 
+    // directly returned as telemetry::Scalar, telemetry::Array, ...
+    // The result here is 1 : [2, 5].
+    const telemetry::AggOperation aggOp0  = {telemetry::AggMethodType::JOIN, "", "1"};
+
+    // Average of read from files in aggfile if there are different types of Scalar(WithUnit)s the return 
+    // type is same as in cpp meaning avg of uint64_t, int64_t and double the result is double.
     const telemetry::AggOperation aggOp1 = {telemetry::AggMethodType::AVG};
+    // Sum of read from files in aggfile
     const telemetry::AggOperation aggOp2 = {telemetry::AggMethodType::SUM};
 
-
-    std::vector<telemetry::AggOperation> aggOps  = {aggOp};
+    // We have to add these aggregation operations into a vector.
+    std::vector<telemetry::AggOperation> aggOps0 = {aggOp0};
     std::vector<telemetry::AggOperation> aggOps1 = {aggOp1};
     std::vector<telemetry::AggOperation> aggOps2 = {aggOp2};
 
-    auto aggFile  = aggFileDir->addAggFile("aggFile", "file[0-9]+", aggOps);
+    // The method for creating an aggregated file is addAggFile
+    // You can specify which of the files from a directory are picked
+    // by regex.
+    auto aggFile0 = aggFileDir->addAggFile("aggFile", "file[0-9]+", aggOps0);
     auto aggFile1 = aggFileDir->addAggFile("aggFile1", "file[0-9]+", aggOps1);
     auto aggFile2 = aggFileDir->addAggFile("aggFile2", "file[0-9]+", aggOps2);
 
-
-    std::cout << telemetry::contentToString(aggFile->read()) << "\n";
+    // Just for showing the results to terminal. The same results will be in the
+    // actual filesystem.
+    std::cout << "Single aggregation operations: \n";
+    std::cout << telemetry::contentToString(aggFile0->read()) << "\n";
     std::cout << telemetry::contentToString(aggFile1->read()) << "\n";
     std::cout << telemetry::contentToString(aggFile2->read()) << "\n";
+
+    // Using two aggregation operations in a single file is only possible when
+    // the sources are dicts.
+    const telemetry::FileOps fileOpsDict1
+        = {[]() { return returnValueDict(2); }, nullptr};
+
+    const telemetry::FileOps fileOpsDict2
+        = {[]() { return returnValueDict(5); }, nullptr};
+
+    auto aggFileDirDict = telemetryRootNode->addDir("aggDirDict");
+    auto fileDict1 = aggFileDirDict->addFile("fileDict1", fileOpsDict1);
+    auto fileDict2 = aggFileDirDict->addFile("fileDict2", fileOpsDict2);
+
+    // The result dict keys have to be different. If they are the same only
+    // the first result is valid and is read.
+    const telemetry::AggOperation aggOpDict0 = {telemetry::AggMethodType::JOIN, "1", "1"};
+    const telemetry::AggOperation aggOpDict1 = {telemetry::AggMethodType::AVG, "1", "2"};
+
+    std::vector<telemetry::AggOperation> aggOpsDict = {aggOpDict0, aggOpDict1};
+
+    auto aggFileDict = aggFileDirDict->addAggFile("aggFileDict", "fileDict[0-9]+", aggOpsDict);
+
+    std::cout << "\nMultiple aggregation operations: \n";
+    std::cout << telemetry::contentToString(aggFileDict->read()) << "\n";
 }