ArangoDB Maintainers Manual =========================== This file contains documentation about the build process and unittests. Put short: if you want to hack parts of arangod this could be interesting for you. For the documentation about the documentation system and process see the [docs repository](https://github.com/arangodb/docs#readme) instead. Main sections: - [Source Code](#source-code) - [Building](#building) - [Running](#running) - [Debugging](#debugging) - [Linux Core Dumps](#linux-core-dumps) - [Windows Core Dumps](#windows-core-dumps) - [Unittests](#unittests) --- Source Code ----------- ### Git Setting up git for automatically merging certain automatically generated files in the ArangoDB source tree: git config --global merge.ours.driver true ### Style Guide See [Documentation/StyleGuide/StyleGuide.pdf](Documentation/StyleGuide/StyleGuide.pdf) for code formatting rules and naming conventions. ### Unique Log Ids We have unique log ids in order to allow for easy locating of code producing errors. LOG_TOPIC("2dead", ....) To ensure that the ids are unique we run the script `./utils/checkLogIds.py` during CI runs. The script will fail with a non-zero status if id collisions are found. You can use `openssl rand -hex 3 | sed 's/.//;s/\(.*\)/"\1"/'` or anything that suits you to generate a **5 hex digit log** id. ### JSLint We switched to eslint a while back, but it is still named jslint for historical reasons. #### Checker Script Use: ./utils/gitjslint.sh to lint your modified files. ./utils/jslint.sh to find out whether all of your files comply to jslint. This is required to make continuous integration work smoothly. If you want to add new files / patterns to this make target, edit the respective shell scripts. To be safe from committing non-linted stuff add **.git/hooks/pre-commit** with: ./utils/jslint.sh #### Use jslint standalone for your js file If you want to search errors in your js file, jslint is very handy - like a compiler is for C/C++. You can invoke it like this: bin/arangosh --jslint js/client/modules/@arangodb/testing.js --- Building -------- ### CMake ArangoDB uses [CMake](https://cmake.org/) for build configuration and packaging. Essentially, you can compile ArangoDB from source by issuing the following commands from a clone of the source repository: mkdir build cd build cmake .. cmake --build . cd .. The first `cmake` command is a configure and generation run and needs to be pointed to the source tree. You can specify a generator like `-G `, e.g. `-G "Visual Studio 15 2017 Win64"` if you want to use a different toolchain than the platform's default (CMake would favor `Visual Studio 16 2019` under Windows if available, but its compiler is not supported by ArangoDB yet). The default under Linux is `-G "Unix Makefiles"`. The second `cmake` command invokes the compiler based on the selected generator / toolchain, which is equivalent to running `make` for Makefiles and the MSVC compiler for a Visual Studio Solution (.sln). For concurrent compilation you may use `cmake --build . -j ` to specify the number of compiler processes (like `make -j`). This requires CMake version 3.12 or higher. You can use `cmake --build . -- -j` in older versions for Unix Makefiles. After that, the binaries will reside in `build/bin` or `build/bin/` in case of a multi-configuration project (supported by Visual Studio, can be `Debug`, `Release`, `RelWithDebInfo`, `MinSizeRel` and passed to CMake like `cmake --config RelWithDebInfo --build .`). To quickly start up your compiled ArangoDB, simply do: build/bin/arangod -c etc/relative/arangod.conf data Under Windows: build\bin\\arangod -c etc\relative\arangod.conf data This will use a configuration file that is included in the source repository. ### CMake Flags These flags can be set in the first call to `cmake`: - `-DUSE_MAINTAINER_MODE=1` - Generate lex/yacc and errors files - `-DUSE_BACKTRACE=1` - Add backtraces to native code asserts & exceptions - `-DUSE_FAILURE_TESTS=1` - Adds JavaScript hook to crash the server for data integrity tests - `-DUSE_GOOGLE_TESTS=On` (default is On so this is set unless you explicitly disable it) Example flags for Windows: - Configure ``` cmake .. -DSTATIC_EXECUTABLE=ON -DOPENSSL_USE_STATIC_LIBS=ON -T "v141,host=x64" -G "Visual Studio 15 2017 Win64" -DUSE_ENTERPRISE=OFF ``` - Build ``` cmake --build . --config RelWithDebInfo --target arangod ``` ### CFLAGS Add backtraces to cluster requests so you can easily track their origin: -DDEBUG_CLUSTER_COMM V8 Special flags: -DENABLE_GDB_JIT_INTERFACE (enable (broken) GDB integration of JIT) At runtime arangod needs to be started with these options: --javascript.v8-options="--gdbjit_dump" --javascript.v8-options="--gdbjit_full" ### Build with AddressSanitizer (or ASan) -DUSE_JEMALLOC=Off -DBASE_LD_FLAGS="-fsanitize=address" -DBASE_CXX_FLAGS="-fsanitize=address -fno-omit-frame-pointer" ### Debugging the build process If the compile goes wrong for no particular reason, appending 'verbose=' adds more output. For some reason V8 has VERBOSE=1 for the same effect. ### Errors in ArangoDB If one changes any error in the ArangoDB system, then one has to: 1. Only touch `lib/Basics/errors.dat` and not the files which are automatically generated from it (`lib/Basics/voc-errors.h`, `lib/Basics/voc-errors.cpp` and `js/common/bootstrap/errors.js`) 2. Always do a full build with `USE_MAINTAINER_MODE` switched ON afterwards, *before* you commit the change. 3. A `make arangod` is not enough! Since it will not recreate these files! *Reason*: These files are only built in maintainer mode, we want that a build in non-maintainer-mode works from every commit. If you only change the generated files, the next build with maintainer mode will delete your changes. ### Building the Web Interface To build Web UI, also known as frontend or *Aardvark*, use CMake in the build directory: cmake --build . --target frontend To remove all available node modules and start a clean installation run: cmake --build . --target frontend_clean The frontend can also be built using these commands: cd /js/apps/system/_admin/aardvark/APP/ npm install grunt deploy For development purposes, go to `js/apps/system/_admin/aardvark/APP/` and open `manifest.json`. Then apply the following change: ``` "/app.js": { - "path": "frontend/build/app.min.js", - "gzip": true + "path": "frontend/build/app.js", + "gzip": false }, ``` Then run `grunt`, `grunt deploy` and `grunt watch`. This should make every change in the code available after a reload for the browser. It is faster this way because the minification step is skipped. Note: You might need to do the same for other files. Usually the change for `app` should suffice however. #### NPM Dependencies To add new NPM dependencies switch into the `js/node` folder and install them with npm using the following options: `npm install [<@scope>/] --global-style --save --save-exact` or simply `npm install [<@scope>/] --global-style -s -E` The `save` and `save-exact` options are necessary to make sure the `package.json` file is updated correctly. The `global-style` option prevents newer versions of npm from unrolling nested dependencies inside the `node_modules` folder. Omitting this option results in exposing *all* dependencies of *all* modules to ArangoDB users. Finally add the module's licensing information to `LICENSES-OTHER-COMPONENTS.md`. When updating dependencies make sure that any mocked dependencies (like `glob` for `mocha`) match the versions required by the updated module and delete any duplicated nested dependencies if necessary (e.g. `mocha/node_modules/glob`) to make sure the global (mocked) version is used instead. --- Running ------- ### Temporary files and temp directories Depending on the native way ArangoDB tries to locate the temporary directory. - Linux/Mac: the environment variable `TMPDIR` is evaluated. - Windows: the [W32 API function GetTempPath()](https://msdn.microsoft.com/en-us/library/windows/desktop/aa364992%28v=vs.85%29.aspx) is called - all platforms: `--temp.path` overrules the above system provided settings. ### Local Cluster Startup The scripts `scripts/startLocalCluster` helps you to quickly fire up a testing cluster on your local machine. `scripts/stopLocalCluster` stops it again. `scripts/startLocalCluster [numDBServers numCoordinators [mode]]` Without arguments it starts 2 DBServers and 1 Coordinator in the background, running on ports 8629, 8630 and 8530 respectively. The agency runs on port 4001. Mode: - `C`: Starts the first Coordinator with `--console` in a separate window (using an `xterm`). - `D`: Starts all DBServers in the GNU debugger in separate windows (using `xterm`s). Hit *ENTER* in the original terminal where the script runs to continue once all processes have been started up in the debugger. --- Debugging --------- ### Runtime - start arangod with `--console` to get a debug console - Cheapen startup for valgrind: `--server.rest-server false --javascript.gc-frequency 1000000 --javascript.gc-interval 65536 --scheduler.threads=1 --javascript.v8-contexts=1` - to have backtraces output set this on the prompt: `ENABLE_NATIVE_BACKTRACES(true)` ### Startup Arangod has a startup rc file: `~/.arangod.rc`. It's evaled as JavaScript. A sample version to help working with the arangod rescue console may look like that: ENABLE_NATIVE_BACKTRACES(true); internal = require("internal"); fs = require("fs"); db = internal.db; time = internal.time; timed = function (cb) { var s = time(); cb(); return time() - s; }; print = internal.print; HINT: You shouldn't lean on these variables in your Foxx services. ### Debugging AQL execution blocks To debug AQL execution blocks, two steps are required: - turn on logging for queries using `--extraArgs:log.level queries=info` - send queries enabling block debugging: `db._query('RETURN 1', {}, { profile: 4 })` You now will get log-entries with the contents being passed between the blocks. ### Core Dumps A core dump consists of the recorded state of the working memory of a process at a specific time. Such a file can be created on a program crash to analyze the cause of the unexpected termination in a debugger. #### Linux Core Dumps ##### Linux Core Dump Generation Generally core dumps have to be enabled using: ulimit -c unlimited You should then see: ulimit -a core file size (blocks, -c) unlimited for each shell and its subsequent processes. Hint: on Ubuntu the `apport` package may interfere with this; however you may use the `systemd-coredump` package which automates much of the following: So that the unit testing framework can autorun gdb it needs to reliably find the corefiles. In Linux this is configured via the `/proc` filesystem, you can make this reboot permanent by creating the file `/etc/sysctl.d/corepattern.conf` (or add the following lines to `/etc/sysctl.conf`) # We want core files to be located in a central location # and know the PID plus the process name for later use. kernel.core_uses_pid = 1 kernel.core_pattern = /var/tmp/core-%e-%p-%t to reload the above settings most systems support: sudo sysctl -p Note that the `proc` paths translate sub-directories to dots. The non permanent way of doing this in a running system is: echo 1 > /proc/sys/kernel/core_uses_pid echo '/var/tmp/core-%e-%p-%t' > /proc/sys/kernel/core_pattern (you may also inspect these files to validate the current settings) More modern systems facilitate [`systemd-coredump`](https://www.freedesktop.org/software/systemd/man/systemd-coredump.html) (via a similar named package) to control core dumps. On most systems it will put compressed core dumps to `/var/lib/systemd/coredump`. In order to use automatic core dump analysis with the unittests you need to configure `/etc/systemd/coredump.conf` and set `Compress=no` - so instant analysis may take place. Please note that we can't support [Ubuntu Apport](https://wiki.ubuntu.com/Apport). Please use `apport-unpack` to send us the bare core dumps. In order to get core dumps from binaries changing their UID the system needs to be told that its allowed to write cores from them. Default ArangoDB installations will do exactly that, so the following is necessary to make the system produce core dumps from production ArangoDB instances: Edit `/etc/security/limits.conf` to contain: ``` arangodb - core infinity ``` Edit the systemd unit file `/lib/systemd/system/arangodb3.service` (USE infinity!!!): ``` ## setting for core files # Any dir that is writable by the user running arangod WorkingDirectory=/var/lib/arangodb3 # core limit - set this to infinity to enable cores LimitCORE=0 ``` Enable new systemd settings: `systemctl daemon-reload && systemctl restart arangodb3.service` Enable suid process dumping: `echo 1 >/proc/sys/fs/suid_dumpable` Make the above change permanent: `echo "sys.fs.suid_dumpable = 1" >> /etc/sysctl.d/99-suid-coredump.conf` **Please note that GDB 8 is required for ArangoDB 3.4 and later; GDB7 won't see threads** You can also generate core dumps from running processes without killing them by using gdb: # sleep 100000 & [2] 6942 # gdb /bin/sleep 6942 ... 0x00007faaa7abd4e4 in __GI___nanosleep (requested_time=0x7ffd047c9940, remaining=0x0) at ../sysdeps/unix/sysv/linux/nanosleep.c:28 gdb> gcore Saved corefile core.6942 gdb> quit Detaching from program: /bin/sleep, process 6942 # ls -l core* -rw-r--r-- 1 me users 352664 Nov 27 10:48 core.6942 ##### Analyzing Core Dumps on Linux We offer debug packages containing the debug symbols for your binaries. Please install them if you didn't compile yourselves. Given you saw in the log of the arangod with the PID `25216` that it died, you should then find `/var/tmp/core-V8 WorkerThread-25216-1490887259` with this information. We may now start GDB and inspect whats going on: gdb /usr/sbin/arangod /var/tmp/*25216* These commands give usefull information about the incident: backtrace full thread apply all bt The first gives the full stacktrace including variables of the last active thread, the later one the stacktraces of all threads. #### Windows Core Dumps For the average \*nix user windows debugging has some awkward methods. ##### Windows Core Dump Generation Core dumps can be created using the task manager; switch it to detail view, the context menu offers to *create dump file*; the generated file ends in a directory that explorer hides from you - AppData - you have to type that in the location bar. This however only for running processes which is not as useful as having dumps of crashing processes. While it is a common feature to turn on core dumps with the system facilities on \*nix systems, it is not as easy in Windows. You need an external program from the *Sysinternals package*: [ProcDump](https://technet.microsoft.com/en-us/sysinternals/dd996900.aspx). First look up the PID of arangod, you can find it in the brackets in the ArangoDB logfile. Then invoke *procdump* like this: procdump -accepteula -e -ma It will keep on running and monitor arangod until eventually a crash happens. You will then get a core dump if an incident occurs or *Dump count not reached.* if nothing happened, *Dump count reached.* if a dump was written - the filename will be printed above. ##### Windows Debugging Symbols Releases are supported by a public symbol server so you will be able to debug cores. Please replace `XX` with the major and minor release number (e.g. `35` for v3.5). Note that you should run the latest version of a release series before reporting bugs. Either [WinDbg](https://docs.microsoft.com/de-de/windows-hardware/drivers/debugger/debugger-download-tools) or Visual Studio support setting the symbol path via the environment variable or in the menu. Given we want to store the symbols on `E:\symbol_cache` we add the ArangoDB symbolserver like this: set _NT_SYMBOL_PATH=SRV*e:\symbol_cache\arango*https://download.arangodb.com/symsrv_arangodbXX/;SRV*e:\symbol_cache\ms*http://msdl.microsoft.com/download/symbols You then will be able to see stack traces in the debugger. You may also try to download the symbols manually using: symchk.exe arangod.exe /s SRV*e:/symbol_cache/cache*https://download.arangodb.com/symsrv_arangodbXX/ The symbolserver over at https://download.arangodb.com/symsrv_arangodbXX/ is browseable; thus you can easily download the files you need by hand. It contains of a list of directories corresponding to the components of ArangoDB: - arango - the basic arangodb library needed by all components - arango_v8 - the basic V8 wrappers needed by all components - arangod - the server process - the client utilities: - arangob - arangobench - arangoexport - arangoimp - arangorestore - arangosh - arangovpack In these directories you will find subdirectories with the hash corresponding to the id of the binaries. Their date should corrospond to the release date of their respective arango release. This means i.e. for ArangoDB 3.1.11: https://download.arangodb.com/symsrv_arangodb31/arangod.pdb/A8B899D2EDFC40E994C30C32FCE5FB346/arangod.pd_ This file is a microsoft cabinet file, which is a little bit compressed. You can extract it by invoking `cabextract` or dismantle it so the Windows Explorer offers you its proper handler by renaming it to .cab; click on the now named `arangod.cab`, copy the contained arangod.pdb into your symbol path. ##### Widnows Core Dump Analysis While Visual studio may cary a nice shiny GUI, the concept of GUI fails miserably e.g. in test automation. Getting an overview over all running threads is a tedious task with it. Here the commandline version of [WinDbg](http://www.windbg.org/) cdb comes to the aid. `testing.js` utilizes it to obtain automatical stack traces for crashes. We run it like that: cdb -z -c 'kp; ~*kb; dv; !analyze -v; q' These commands for `-c` mean: kp print curren threads backtrace with arguments ~*kb print all threads stack traces dv analyze local variables (if) !analyze -v print verbose analysis q quit the debugger If you don't specify them via `-c` you can also use them in an interactive manner. Alternatively you can also directly specify the symbol path via the `-y` parameter (replace XX): cdb -z -y 'SRV*e:\symbol_cache*https://download.arangodb.com/symsrv_arangodbXX;SRV*e:\symbol_cache\ms*http://msdl.microsoft' and use the commands above to obtain stacktraces. --- Unittests --------- ### Dependencies - *Ruby*, *rspec*, *httparty*; to install the required dependencies run the following commands in the source root: ``` gem install bundler cd tests/rb/HttpInterface bundler ``` - *Google Test* (compile time, shipped in the 3rdParty directory) ### Folder Locations There are several major places where unittests live: | Path | Description |:-----------------------------|:----------------------------- | `tests/js/server/` | JavaScript tests, runnable on the server | `tests/js/common/` | JavaScript tests, runnable on the server & via arangosh | `tests/js/common/test-data/` | Mock data used for the JavaScript tests | `tests/js/client/` | JavaScript tests, runnable via arangosh | `tests/rb/` | rspec tests (Ruby) | `tests/rb/HttpInterface/` | rspec tests using the plain RESTful interface of ArangoDB. Include invalid HTTP requests and error handling checks for the server. | `tests/` (remaining) | Google Test unittests ### Filename conventions Special patterns in the test filenames are used to select tests to be executed or skipped depending on parameters: | Substring | Description |:----------------|:---------------- | `-cluster` | These tests will only run if clustering is tested (option 'cluster' needs to be true). | `-noncluster` | These tests will only run if no cluster is used (option 'cluster' needs to be false) | `-timecritical` | These tests are critical to execution time - and thus may fail if arangod is to slow. This may happen i.e. if you run the tests in valgrind, so you want to avoid them since they will fail anyways. To skip them, set the option `skipTimeCritical` to *true*. | `-disabled` | These tests are disabled. You may however want to run them by hand. | `-spec` | These tests are run using the mocha framework instead of jsunity. | `-nightly` | These tests produce a certain thread on infrastructure or the test system, and therefore should only be executed once per day. | `-grey` | These tests are currently listed as "grey", which means that they are known to be unstable or broken. These tests will not be executed by the testing framework if the option `--skipGrey` is given. If `--onlyGrey` option is given then non-"grey" tests are skipped. See `tests/Greylist.txt` for up-to-date information about greylisted tests. Please help to keep this file up to date. ### Javascript Framework Since several testing technologies are utilized, and different ArangoDB startup options may be required (even different compilation options may be required) the framework is split into testsuites. Get a list of the available testsuites and options by invoking: ./scripts/unittest To locate the suite(s) associated with a specific test file use: ./scripts/unittest find --test tests/js/common/shell/shell-aqlfunctions.js Run all suite(s) associated with a specific test file: ./scripts/unittest auto --test tests/js/common/shell/shell-aqlfunctions.js Run all tests: scripts/unittest all `scripts/unittest` is only a wrapper for the most part, the backend functionality lives in `js/client/modules/@arangodb/` (`testing.js`, `process-utils.js`, `test-utils.js`). The actual testsuites are located in the `testsuites` subfolder. #### Passing Options The first parameter chooses the facility to execute. Available choices include: - **all**: This target is utilized by most of the Jenkins builds invoking unit tests (calls multiple) - **single_client**: (see [Running a single unittest suite](#running-a-single-unittest-suite)) - **single_server**: (see [Running a single unittest suite](#running-a-single-unittest-suite)) Different facilities may take different options. The above mentioned usage output contains the full detail. Instead of starting its own instance, `unittest` can also make use of a previously started arangod instance. You can launch the instance as you want including via a debugger or `rr` and prepare it for what you want to test with it. You then launch the test on it like this (assuming the default endpoint): ./scripts/unittest http_server --server tcp://127.0.0.1:8529/ A commandline for running a single test (-> with the facility 'single_server') using valgrind could look like this. Options are passed as regular long values in the syntax --option value --sub:option value. Using Valgrind could look like this: ./scripts/unittest single_server --test tests/js/server/aql/aql-escaping.js \ --extraArgs:server.threads 1 \ --extraArgs:scheduler.threads 1 \ --extraArgs:javascript.gc-frequency 1000000 \ --extraArgs:javascript.gc-interval 65536 \ --extraArgs:log.level debug \ --extraArgs:log.force-direct true \ --javascript.v8-contexts 2 \ --valgrind /usr/bin/valgrind \ --valgrindargs:log-file /tmp/valgrindlog.%p - We specify the test to execute - We specify some arangod arguments via --extraArgs which increase the server performance - We specify to run using valgrind (this is supported by all facilities) - We specify some valgrind commandline arguments - We set the log level to debug - We force the logging not to happen asynchronous - Eventually you may still add temporary `console.log()` statements to tests you debug. #### Running a Single Unittest Suite Testing a single test with the framework directly on a server: scripts/unittest single_server --test tests/js/server/aql/aql-escaping.js You can also only execute a filtered test case in a jsunity/mocha/gtest test suite (in this case `testTokens`): scripts/unittest single_server --test tests/js/server/aql/aql-escaping.js --testCase testTokens scripts/unittest shell_client --test shell-util-spec.js --testCase zip scripts/unittest gtest --testCase IResearchDocumentTest.* Testing a single test with the framework via arangosh: scripts/unittest single_client --test tests/js/client/shell/shell-transaction.js Testing a single rspec test: scripts/unittest http_server --test api-users-spec.rb Running a test against a server you started (instead of letting the script start its own server): scripts/unittest http_server --test api-batch-spec.rb --server tcp://127.0.0.1:8529 --serverRoot /tmp/123 #### Running Foxx Tests with a Fake Foxx Repo Since downloading Foxx apps from GitHub can be cumbersome with shaky DSL and DoS'ed GitHub, we can fake it like this: export FOXX_BASE_URL="http://germany/fakegit/" ./scripts/unittest single_server --test 'tests/js/server/shell/shell-foxx-manager-spec.js' ### Running jsUnity Tests Assume that you have a test file containing: ```js function exampleTestSuite () { return { testSizeOfTestCollection : function () { assertEqual(5, 5); }; } jsUnity.run(aqlTestSuite); return jsunity.done(); ``` Then you can run the test suite using `jsunity.runTest()`: ``` arangosh> require("jsunity").runTest("test.js"); 2012-01-28T19:10:23Z [10671] INFO Running aqlTestSuite 2012-01-28T19:10:23Z [10671] INFO 1 test found 2012-01-28T19:10:23Z [10671] INFO [PASSED] testSizeOfTestCollection 2012-01-28T19:10:23Z [10671] INFO 1 test passed 2012-01-28T19:10:23Z [10671] INFO 0 tests failed 2012-01-28T19:10:23Z [10671] INFO 1 millisecond elapsed ``` #### Running jsUnity Tests with arangod In (emergency) console mode (`arangod --console`): require("jsunity").runTest("tests/js/server/aql/aql-escaping.js"); Filtering for one test case (in this case `testTokens`) in console mode: require("jsunity").runTest("tests/js/server/aql/aql-escaping.js", false, "testTokens"); #### Running jsUnity Tests with arangosh client Run tests this way: require("jsunity").runTest("tests/js/client/shell/shell-client.js"); You can only run tests which are intended to be ran via arangosh. ### Mocha Tests All tests with `-spec` in their names are using the [mochajs.org](https://mochajs.org) framework. To run those tests, e.g. in the arangosh, use this: require("@arangodb/mocha-runner").runTest('tests/js/client/endpoint-spec.js', true) ### Debugging Tests This is quick introduction only. Running a single rspec test: ./scripts/unittest http_server --test api-import-spec.rb Debugging rspec with gdb: server> ./scripts/unittest http_server --test api-import-spec.rb --server tcp://127.0.0.1:7777 - or - server> ARANGO_SERVER="127.0.0.1:6666" rspec -Itests/rb/HttpInterface --format d --color tests/rb/HttpInterface/api-import-spec.rb client> gdb --args ./build/bin/arangod --server.endpoint http+tcp://127.0.0.1:6666 --server.authentication false --log.level communication=trace ../arangodb-data-test-mmfiles Debugging a storage engine: host> rm -fr ../arangodb-data-rocksdb/; gdb --args ./build/bin/arangod --console --server.storage-engine rocksdb --foxx.queues false --server.statistics false --server.endpoint http+tcp://0.0.0.0:7777 ../arangodb-data-rocksdb (gdb) catch throw (gdb) r arangod> require("jsunity").runTest("tests/js/client/shell/shell-client.js"); ### Running tcpdump / windump for the SUT Don't want to miss a beat of your test? If you want to invoke tcpdump with sudo, make sure that your current shell has sudo enabled. Try like this: sudo /bin/true; ./scripts/unittest http_server \ --sniff sudo --cleanup false The pcap file will end up in your tests temporary directory. You may need to press an additional `ctrl+c` to force stop the sudo'ed tcpdump. On Windows you can use TShark, you need a npcap enabled installation. List your devices to sniff on using the -D option: c:/Program\ Files/wireshark/tshark.exe -D 1. \Device\NPF_{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX} (Npcap Loopback Adapter) 2. \Device\NPF_{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX} (Ethernet) 3. \\.\USBPcap1 (USBPcap1) Choose the `Npcap Loopback Adapter` number - 1: ./scripts/unittest http_server \ --sniff true \ --cleanup false \ --sniffDevice 1\ --sniffProgram c:/Programm Files/wireshark/tshark.exe You can later on use Wireshark to inpsect the capture files.