Argument --settings is ineffective for Release v1.3.1-linux Blocks environment

[wangwwno1]

OS: Ubuntu 18.04
AirSim: v1.3.1-linux(release)
Python: 3.8.4
Unreal Engine: 4.24.3

This doc said I can specify customized settings.json through argument --settings or -s. However, this argument seems ineffective for the Blocks environment downloaded from the same releases page.

How to replicate:

• navigate to the Blocks package folder
• run ./Blocks.sh --settings '{"SimMode": "Multirotor"}' in the terminal console

Result: Pop-up "Choose Vehicle"window that ask to use car or quadcopter
Expect: No pop-up window

Edit: This issue disappeared after:

• pull the master branch
• rebuild and package the Blocks environment
• use pexpect.spawn to send arguments instead of the terminal console in ubuntu

Here is my python code with pexpect.spawn

import airsim
import pexpect

s = '{"SimMode": "Multirotor"}'
task = pexpect.spawn(f"/home/$USER/path/to/Blocks.sh --settings {s}", encoding="utf-8")
while line.find("LogLoad: (Engine Initialization)") == -1:
     line = task.readline()
client = airsim.MultirotorClient()
print(client.confirmConnection())

The resuslt would be:

Connected!
Client Ver:1 (Min Req: 1), Server Ver:1 (Min Req: 1)

I'm not sure the root of this problem, maybe there is something wrong in the terminal console.

Edit: Passing settings as argument to pexpect.spawn, however, is ineffective

# The setting will be ineffective
task = pexpect.spawn(f"/home/$USER/path/to/Blocks.sh", args=["--settings", s], encoding="utf-8")

[ahmed-elsaharti]

Hi @wangwwno1 , the feature was introduced in #2668 which was merged a couple of months after the 1.3.1 release. If you clone the latest repo and compile the binary through the included Blocks development environment this would probably work.

[wangwwno1]

Hi @wangwwno1 , the feature was introduced in #2668 which was merged a couple of months after the 1.3.1 release. If you clone the latest repo and compile the binary through the included Blocks development environment this would probably work.

Thanks! I'll give a try!

[wangwwno1]

Get an error during package process, just like issue #2957:
SegmentationMaterial.uasset was saved with a newer custom version than the current
Removing SegmentationMaterial.uasset can partially resolve this issue.

Current Status:
./Blocks.sh --settings '/home/$USER/path/to/settings.json' is NOT work
./Blocks.sh --settings /home/$USER/path/to/settings.json is OK(with quotation marks removed)

./Blocks.sh --settings '{ "SettingsVersion": 1.2, "SimMode": "Multirotor" }' is NOT work
./Blocks.sh --settings ' " {\"SimMode\":\"Multirotor\"} " ' is OK

[wangwwno1]

It looks like the UnrealEngine parser won't process json strings without opening and closing quote.
Therefore, to passing json text in command line, one should rewrite
'{"SettingsVersion": 1.2, "SimMode": "Multirotor"}'
into
'"{\"SettingsVersion\": 1.2, \"SimMode\":\"Multirotor\"}"'

[wangwwno1]

@ahmed-elsaharti
This issue disappeared in pexpect.spawn, so maybe there is something wrong in my ubuntu terminal console.
Could you replicate this problem in the same system? Here is the process:

• navigate to the Blocks package folder
• run ./Blocks.sh --settings '{"SimMode": "Multirotor"}' in the terminal console

Result: Pop-up "Choose Vehicle"window that ask to use car or quadcopter
Expect: No pop-up window

[ahmed-elsaharti]

I currently don't have access to my Linux system. However, I'll compile a binary using the latest repo on my Windows system and test this.
I'll report back ASAP.

[ahmed-elsaharti]

Here's what I found so far (for Windows):
Block --settings C:\Path\to\settings.json
and
Block --settings "C:\Path\to\settings.json"
work perfectly

Block --settings 'C:\Path\to\settings.json' does NOT. Neither does any form of passing the actual settings string to the parser

[wangwwno1]

Here's what I found so far (for Windows):
Block --settings C:\Path\to\settings.json
and
Block --settings "C:\Path\to\settings.json"
work perfectly

Block --settings 'C:\Path\to\settings.json' does NOT. Neither does any form of passing the actual settings string to the parser

Thanks for the response! I got similar result on Ubuntu 18.04 terminal console.
Both ./Blocks.sh --settings /home/$USER/path/to/settings.json and ./Blocks.sh --settings "/home/$USER/path/to/settings.json" are OK while ./Blocks.sh --settings '/home/$USER/path/to/settings.json' is not.

The console encoding is en_US.UTF-8, identical with the pexpect code, so the root may not be there.
Perhaps I should move on with pexpect.spawn...

[niwc-jamelc]

I was experiencing the same issue with the --settings command line launch argument not working when launching AirSim as a Standalone game from the Unreal Editor on Windows 11. Upon further investigation into the SimHud.cpp and settings.md files, I found that the bool ASimHUD::getSettingsTextFromCommandLine(std::string& settingsText) function was poorly implemented and inconsistently documented.

The function does not properly support passing a json object with --settings, and the argument fails to be read if any other command line arguments and values exists after --setting. The implementation goes against the UE4's convention for passing and reading command line launch arguments.

FParse::Param is used for reading argument flags (ex: -flag), FParse::Value is used for reading arguments that pass along a number or string (ex: -number=1 -string="I'm a string"). The only way to pass a json object with FParse::Value is to make sure the remove all the whitespace and set the bStopOnSeperators flag to false for FParse::Value (ex: {"foo1":"bar1","foo2":"bar2"})

Here is my suggested fixes to SimHud.cpp and settings.md

Change the settings command line argument from --settings to be -settings= to follow UE4 conventions.

SimHud.cpp

// Attempts to parse the settings file path or the settings text from the command line
// Looks for the flag "-settings=". If it exists, settingsText will be set to the value.
// Example (Path): AirSim.exe -settings="C:\path\to\settings.json"
// Example (Text): AirSim.exe -settings={"foo":"bar"} -> settingsText will be set to {"foo":"bar"}
// Returns true if the argument is present, false otherwise.
bool ASimHUD::getSettingsTextFromCommandLine(std::string& settingsText)
{
    const TCHAR* commandLineArgs = FCommandLine::Get();
    FString settingsJsonFString;

    if (FParse::Value(commandLineArgs, TEXT("-settings="), settingsJsonFString, false)) {
        if (readSettingsTextFromFile(settingsJsonFString, settingsText)) {
            return true;
        }
        else {
            UAirBlueprintLib::LogMessageString("Loaded settings from commandline: ", TCHAR_TO_UTF8(*settingsJsonFString), LogDebugLevel::Informational);
            settingsText = TCHAR_TO_UTF8(*settingsJsonFString);
            return true;
        }
    }

    return false;
}

settings.md

# AirSim Settings

## Where are Settings Stored?
AirSim is searching for the settings definition in the following order. The first match will be used:

1. Looking at the (absolute) path specified by the `-settings` command line argument.
For example, in Windows: `AirSim.exe -settings="C:\path\to\settings.json"`
In Linux `./Blocks.sh -settings="/home/$USER/path/to/settings.json"`

2. Looking for a json document passed as a command line argument by the `-settings` argument.
For example, in Windows: `AirSim.exe -settings={"foo":"bar"}`
In Linux `./Blocks.sh -settings={"foo":"bar"}`

....

[jonyMarino]

Thanks, @niwc-jamelc for sharing a fix. Why don't you submit a pull request?

[niwc-jamelc]

@jonyMarino Apologies for the delay. I've created a pull request.