Tech Notes

IPC communication between Docker containers

Have you seen Shared Memory with Docker containers (docker version 1.4.1)? It sounds like you need to share the volume where the IPC lives and also set --ipc host. In your example, it would be something like:

# Container #1
docker run -it --name c1 -v /tmp:/tmp --ipc=host container1

# Container #2
docker run -it --name c2 -v /tmp:/tmp --ipc=host container2

I have 3 containers, 2 containers share data to another container, what worked for me is:

# container 1
docker run -it --ipc=shareable -v ///tmp --network=host --name node container1

# container 2
docker run -it --ipc=container:node --volumes-from node --network=host --name mdns container2

# container 3
docker run -it --ipc=container:node --volumes-from node --network=host --name connection container3

container1 can get pid of processes running in container2 and container3 and hence get data from the containers.

IPC communication between Docker containers

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bootstrap modal not working at all

Check the version of bootstrap. Take attention that in bootstrap 5 changed data-toggle to data-bs-toggle and data-target to data-bs-target

have you used the cdn or file popper.js
If you not include popper.js file you wont be able to see your modal windows
check the below cdn and put below jquery.js and bootstrap.js as follows below

<script src=https://code.jquery.com/jquery-3.2.1.slim.min.js integrity=sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN crossorigin=anonymous></script>
<script src=https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.3/umd/popper.min.js integrity=sha384-vFJXuSJphROIrBnz7yo7oB41mKfc8JzQZiCq4NCceLEaO4IHwicKwpJf9c9IpFgh crossorigin=anonymous></script>
<script src=https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/js/bootstrap.min.js integrity=sha384-alpBpkh1PFOepccYVYDB4do5UnbKysX5WZXm3XxPqe5iKTfUKjNkCk9SaVuEZflJ crossorigin=anonymous></script>

Now it will work 100% if not I have another solution
copy the below code and check it

<button type=button class=btn btn-primary data-toggle=modal data-target=#exampleModal>
  Launch demo modal
</button>

<div class=modal fade id=exampleModal tabindex=-1 role=dialog aria-labelledby=exampleModalLabel aria-hidden=true>
  <div class=modal-dialog role=document>
    <div class=modal-content>
      <div class=modal-header>
        <h5 class=modal-title id=exampleModalLabel>Modal title</h5>
        <button type=button class=close data-dismiss=modal aria-label=Close>
          <span aria-hidden=true>&times;</span>
        </button>
      </div>
      <div class=modal-body>
        ...
      </div>
      <div class=modal-footer>
        <button type=button class=btn btn-secondary data-dismiss=modal>Close</button>
        <button type=button class=btn btn-primary>Save changes</button>
      </div>
    </div>
  </div>
</div>

bootstrap modal not working at all

Add this line to Javascript file

  $(document).ready(function() {
    $(#MyModal).modal();
  });

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Visual Studio Code how to resolve merge conflicts with git?

With VSCode you can find the merge conflicts easily with the following UI.

(if you do not have the topbar, set editor.codeLens: true in User Preferences)

It indicates the current change that you have and incoming change from the server. This makes it easy to resolve the conflicts – just press the buttons above <<<< HEAD.

If you have multiple changes and want to apply all of them at once – open command palette (View -> Command Palette) and start typing merge – multiple options will appear including Merge Conflict: Accept Incoming, etc.

After trial and error I discovered that you need to stage the file that had the merge conflict, then you can commit the merge.

Visual Studio Code how to resolve merge conflicts with git?

For those who are having a hard time finding the merge buttons.

The little lightbulb icon with the merge options only shows up if you click precisely on the merge conflict marker:

<<<<<<<

Steps (in VS Code 1.29.x):

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java – Void methods cannot return a value

You should be defining your method outside of main, like:

public class YourClass
{
    public static void main(String... args)
    {

    }

    public char yourMethod()
    {
         //...
    }
}

Java does not support nested methods; however, there are workarounds, but they are not what youre looking for.

As for your question about args, it is simply an array of Strings that correspond to command line arguments. Consider the following:

public static void main(String... args) //alternative to String[] args
{
    for (String argument: args)
    {
        System.out.println(argument);
    }
}

Executing via java YourClass Hello, World!

Will print

Hello,
Word!

You cannot declare a method (toLower) inside another method (main).

java – Void methods cannot return a value

Yes void return type can not return any value.

It will be better if you create a separate function for this process which will return some value and call it from main().

public class Test
{
    public static void main(String[] args)
    {
        String[] a = testMethod();
    }

    public String[] testMethod()
    {
        .....
        .....
        return xx;
    }
}

Hope it will help you.

Thanks

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r – Error in Confusion Matrix : the data and reference factors must have the same number of levels

Do table(pred) and table(testing$Final). You will see that there is at least one number in the testing set that is never predicted (i.e. never present in pred). This is what is meant why different number of levels. There is an example of a custom made function to get around this problem here.

However, I found that this trick works fine:

table(factor(pred, levels=min(test):max(test)), 
      factor(test, levels=min(test):max(test)))

It should give you exactly the same confusion matrix as with the function.

I had the same issue.
I guess it happened because data argument was not casted as factor as I expected.
Try:

confusionMatrix(pred,as.factor(testing$Final))

hope it helps

r – Error in Confusion Matrix : the data and reference factors must have the same number of levels

confusionMatrix(pred,testing$Final)

Whenever you try to build a confusion matrix, make sure that both the true values and prediction values are of factor datatype.

Here both pred and testing$Final must be of type factor. Instead of check for levels, check the type of both the variables and convert them to factor if they are not.

Here testing$final is of type int. conver it to factor and then build the confusion matrix.

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javascript – Uncaught SyntaxError: Invalid or unexpected token

You should pass @item.email in quotes then it will be treated as string argument

<td><a href ="#"  onclick="Getinfo('@item.email');" >6/16/2016 2:02:29 AM</a>  </td>

Otherwise, it is treated as variable thus error is generated.

The accepted answer work when you have a single line string(the email) but if you have a

multiline string, the error will remain.

Please look into this matter:

<!-- start: definition-->
@{
    dynamic item = new System.Dynamic.ExpandoObject();
    item.MultiLineString = @"a multi-line
                             string";
    item.SingleLineString = "a single-line string";
}
<!-- end: definition-->
<a href="#" onclick="Getinfo('@item.MultiLineString')">6/16/2016 2:02:29 AM</a>
<script>
    function Getinfo(text) {
        alert(text);
    }
</script>

Change the single-quote(‘) to backtick(`) in Getinfo as bellow and error will be fixed:

<a href="#" onclick="Getinfo(`@item.MultiLineString`)">6/16/2016 2:02:29 AM</a>

javascript – Uncaught SyntaxError: Invalid or unexpected token

I also had an issue with multiline strings in this scenario. @Iman’s backtick(`) solution worked great in the modern browsers but caused an invalid character error in Internet Explorer. I had to use the following:

'@item.MultiLineString.Replace(Environment.NewLine, "<br />")'

Then I had to put the carriage returns back again in the js function. Had to use RegEx to handle multiple carriage returns.

// This will work for the following:
// "hellonworld"
// "hello<br>world"
// "hello<br />world"
$("#MyTextArea").val(multiLineString.replace(/n|<brs*/?>/gi, "r"));

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What the meaning of Bootstrap 5 class me-auto

mr-auto => bootstrap 4 margin right-auto

me-auto => bootstrap 5 margin end-auto

https://getbootstrap.com/docs/5.0/utilities/spacing/#margin-and-padding

Changing .me-auto to .ms-auto shifts it to the right.

What the meaning of Bootstrap 5 class me-auto

For ul position left to right use

<ul class=nav justify-content-end>

me-auto meening bootstrap 5 margin end-auto

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sockets – What is java.net.NoRouteToHostException: Cannot assign requested address?

hey can you check you request is use keep-Alive option? If you are doing a stress test, please try turning it off.

Signals that an error occurred while attempting to connect a socket to a remote address and port. Typically, the remote host cannot be reached because of an intervening firewall, or if an intermediate router is down.
Read this Documnet

https://docs.oracle.com/javase/7/docs/api/java/net/NoRouteToHostException.html

you can also go through these answers

• How to avoid a NoRouteToHostException?
• NoRouteToHostException on client or server?

sockets – What is java.net.NoRouteToHostException: Cannot assign requested address?

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python 3.x – Virtualenv – workon command not found

So far it was working fine but I restarted the shell

The reason is because you restarted the shell.

If you want this to work with each shell, youll need to add these to your ~/.bashrc file:

export WORKON_HOME=~/.virtualenvs
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
source /usr/local/bin/virtualenvwrapper.sh

After adding this, youll want to source ~/.bashrc so the changes take effect. Youll find that you have access to virtualenvwrapper facilities in each new shell.

You need to add commands

export WORKON_HOME=~/.virtualenvs
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
source /usr/local/bin/virtualenvwrapper.sh

to your ~/.bashrc file. So that whenever you start shell these commands are loaded automatically.

For the reference.

python 3.x – Virtualenv – workon command not found

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android – ArrayAdapter requires the resource ID to be a TextView XML problems

The ArrayAdapter requires the resource ID to be a TextView XML exception means you dont supply what the ArrayAdapter expects. When you use this constructor:

new ArrayAdapter<String>(this, R.layout.a_layout_file, this.file)

R.Layout.a_layout_file must be the id of a xml layout file containing only a TextView(the TextView cant be wrapped by another layout, like a LinearLayout, RelativeLayout etc!), something like this:

<?xml version=1.0 encoding=utf-8?>
<TextView xmlns_android=http://schemas.android.com/apk/res/android
    android_layout_width=fill_parent
    android_layout_height=wrap_content 
    // other attributes of the TextView
/>

If you want your list row layout to be something a little different then a simple TextView widget use this constructor:

new ArrayAdapter<String>(this, R.layout.a_layout_file, 
   R.id.the_id_of_a_textview_from_the_layout, this.file)

where you supply the id of a layout that can contain various views, but also must contain a TextView with and id(the third parameter) that you pass to your ArrayAdapter so it can know where to put the Strings in the row layout.

Soution is here

listitem.xml

<?xml version=1.0 encoding=utf-8?>
<LinearLayout xmlns_android=http://schemas.android.com/apk/res/android
     android_layout_width=match_parent
     android_layout_height=match_parent
     android_orientation=vertical >

     <TextView
         [email protected]+id/textview
         android_layout_width=match_parent
         android_layout_height=match_parent >
     </TextView>
</LinearLayout>

Java code :

 String[] countryArray = {India, Pakistan, USA, UK};
 ArrayAdapter adapter = new ArrayAdapter<String>(this, R.layout.listitem,R.id.textview, countryArray);
 ListView listView = (ListView) findViewById(R.id.listview);
 listView.setAdapter(adapter);

android – ArrayAdapter requires the resource ID to be a TextView XML problems

If you are getting that message when you are extending an ArrayAdapter, you are getting that error because you have not provided the correct resource id to display the item. Call the super class in the constructor and pass in the resource id of the TextView:

    //Pass in the resource id:  R.id.text_view
    SpinnerAdapter spinnerAddToListAdapter = new SpinnerAdapter(MyActivity.this,
            R.id.text_view,
            new ArrayList<>());

Adapter:

public class SpinnerAdapter extends ArrayAdapter<MyEntity> {

    private Context context;
    private List<MyEntity> values;

    public SpinnerAdapter(Context context, int textViewResourceId,
                          List<MyEntity> values) {

        //Pass in the resource id:  R.id.text_view
        super(context, textViewResourceId, values);

        this.context = context;
        this.values = values;
    }

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