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History of a bug

Introscope & SAML (saml.jsp)

Rédigé par gorki Aucun commentaire

Problem :

I tried to connect Broadcom Introscope 10.7 and SAML given by Keycloak.

Based on these documents : 

Well not enough to make it works.

Solution :

Thanks to remote debug mode, the key is that the callback URL is : 

https://<webview url>/saml.jsp

Search for saml.jsp + introscope on google. Good luck.

Here are the steps (assuming that you already have a keycloak realm up and ready) : 

Step 1 : IntroscopeEnteprise.properties

introscope.saml.enable=true
introscope.saml.request.binding=POST
introscope.saml.idpUrl=<URL_KEYCLOAK>/realms/<your realm>/protocol/saml
introscope.saml.issuer=com.ca.apm.webview.serviceprovider
introscope.saml.webstart.issuer=com.ca.apm.webstart.serviceprovider
introscope.saml.em.issuer=com.ca.apm.em.serviceprovider
introscope.saml.principalAttributeName=principalName
introscope.saml.groupsAttributeName=groups
introscope.saml.webstart.tokenTimeoutInSeconds=60
introscope.saml.internalIdp.enable=false
# introscope.saml.internalIdpUrl=http://localhost:8080/idp/profile/SAML2/POST/SSO

Step 2 : Keycloak configuration

  1. Create a client named as introscope.saml.issuer so in our case :  com.ca.apm.webstart.serviceprovider
  2. Enter the callback URL in Master SAML Processing URL : https://<webview url>/saml.jsp

Step 3 : Certificates

You should secure you communication between Introscope and Keycloak : 

  1. Provide HTTPS for Keycloak
  2. Provide HTTPS for Introscope
  3. Sign information in Keycloak client
  4. Import Keycloak key in a JKS truststore for Java (Webview part). Keycloak client certificate are in the client definition, tab “Keys”.
    1. Follow Official guide to create the JKS
  5. Point to this truststore (example : spprivatekey.jks) - next steps.

Step 4 : IntroscopeWebview.properties:

apm.webview.saml.sp.truststore=/path/to/spprivatekey.jks

Introscope & Unsupported major.minor version 52.0

Rédigé par gorki Aucun commentaire

Problem :

Launching a JVM with Introscope agent on a old JVM 1.7 result in : 

A problem occurred while attempting to create the delegate agent 
[IntroscopeAgent] Agent Unavailable 

Well, as the agent is heavily customized, removing customization was the first step. It starts. 
OK, a few lambda removing alter, I recompiled everything with Java 1.7 target.. And still the same message. 

Solution : 

After a hours ... 

Step 1 : 

  • Decompile
    • com.wily.introscope.agent.AgentShim
  • Add more logs, it confirms this is a class loading problem with major/minor version. I finally get the class name 

Step 2 : 

  • After checking X times my maven settings, I finally used : *
    • javap -v | grep version
    • to check if it was ok or not. 
  • and surprisingly, the generated class was OK ! 
  • but I used also assembly plugin 

Step 3 : 

  • The cause was that I recompile some classes of an old jar and rebuild it 
  • I tracked the faulty classes version in the different repositories  The root cause was that I installed in a local repository the old jar without the modified classes with the command : 
plaintext mvn install:install-file -DcreateChecksum=true -Dfile=./agent/wily/Agent.jar -DgroupId=com.ca.agent -DartifactId=javaagent -Dversion=10.0.7SP3 -Dpackaging=jar -DlocalRepositoryPath=local-maven-repo

which install it also after build in the global repository... 

And assembly plugin use in priority the global repository. 

Well I didn't take time to understand why maven do not use only my local repository for this jar. 

I just add : rm -rf ~/.m2/repository/com/ca/agent/sqlagent in the beginning of my install script  ! 

Well a few hours lost again here...

React and events

Rédigé par gorki Aucun commentaire

Problème :

J'utilise React pour développer une application frontend et j'utilise les méthodes de base Javascsript pour gérer les événements venant du serveur ou en interne Front.

J'ai trouvé sur internet quelques fonctions utiles pour gérer les événements (je n'ai pas retrouvé où !) :

  • on : abonnement
  • off : désabonnement
  • trigger : déclencher un évenement

Pour mon usage, j'ai customisé ces fonctions en ajoutant une callback en paramètre. Résultat j'ai ce code : 

function on(eventType:string, state:any, listener:(detail:MyEvent) => void) {
    const resultFunction = function(event:any) {
        listener(event.detail)
    };
    document.addEventListener(eventType, resultFunction);

Cela me permet de gérer des événements qui héritent de MyEvent.

Le problème est que, ce faisant, je crée une fonction anonyme à chaque souscription et que du coup il est impossible d'utiliser removeEventListener lorsque le composant se démonte.

Solution :

Indirectement c'est ce guide qui m'a aidé : https://dev.to/marcostreng/how-to-really-remove-eventlisteners-in-react-3och

L'idée était donc bien de garder la référence à la fonction anonyme créée (qui me permet de gérer des callbacks génériques), mais comment simplifier l'usage pour éviter de devoir faire stocker la référence à cette fonction anonyme par tous les composants ?

Eh bien en la stockant moi-même directement dans le state !

Sur le désabonnement, je vais chercher dans le state, la référence à la fonction anonyme stockée pour mon type d'événement.


function buildKey(eventType: string) {
    return 'clientside-events.listener.' + eventType;
}

function on(eventType:string, state:any, listener:(detail:MyEvent) => void) {
    const resultFunction = function(event:any) {
        listener(event.detail)
    };
    document.addEventListener(eventType, resultFunction);
    if (state !== null) {
        if (!state.listeners) {
            state.listeners = new Map();
        }
        state.listeners.set(buildKey(eventType), resultFunction);
    }
    return resultFunction;
}

function off(eventType:string, state:any) {
    if (state !== null && state.listeners) {
        document.removeEventListener(eventType, state.listeners.get(buildKey(eventType)));
    } else {
        console.warn('Trying to remove a listener but not found for ' + eventType)
    }
}

function trigger(eventType:string, message:ShaanEvent) {
    const event = new CustomEvent(eventType, { detail: message });
    document.dispatchEvent(event);
}

export { on, off, trigger };

 

Cannot create GC thread but a lot of memory

Rédigé par gorki Aucun commentaire

Problem :

Launching a JVM I have the message : "Cannot create GC thread. Out of system resources"

  • Enough memory
  • Enough swap
  • Enough ulimit
  • Enough threads-max
  • Enough CPU

Event extend the PID limit...

Important (at the end) : debian version = 10.11

Solution :

After a hours of googling, I found :

But none of these solutions works and none was matching the number I had :

  • number of open files < ulimit -n
  • maximum process/tasks < ulimit -u

But in a thread, I found something that was working : UserTasksMax.
I'm running SystemD, I have around 10805 task running for my user.
And from : https://manpages.debian.org/stretch/systemd/logind.conf.5.en.html

UserTasksMax=

Sets the maximum number of OS tasks each user may run concurrently. This controls the TasksMax= setting of the per-user slice unit, see systemd.resource-control(5) for details. If assigned the special value "infinity", no tasks limit is applied. Defaults to 33%, which equals 10813 with the kernel's defaults on the host, but might be smaller in OS containers.

For my suspect PID (a lot of files) :

  • cat /proc/21890/status | grep Thread => 1 thread
  • ls /proc/21890/task | wc
  • confirmed by the usual command : ps -eLf | grep calrisk | wc

I have around 10805 threads running for a given JVM very close to the limit.

Complete guide :

https://www.journaldufreenaute.fr/nombre-maximal-de-threads-par-processus-sous-linux/

Parameters not present in all man page, it could grown up to 12288 on latest version.

To be check !

 

 

How-to extend Angular mat-table

Rédigé par gorki Aucun commentaire

Problem :

I would like to have a common table component that makes :

  • table, multicolumn
  • customize row renderer
  • sort
  • pagination
  • export
  • filtering

Well I'm using angular-material, not bad and with mat-table out of the box :

  • sorting : MatSort
  • pagination : MatPaginator
  • export : MatExporter with this extension

But integrate a filter (I try from the same author this one) was not as good as I wanted.

Solution :

After a few hours of googling, I found :

  • An extension : https://github.com/kerrexwong/ExtendedMatTable
    • But there wasn't the possibility to customize the content of the column
    • It was the source of the idea
  • A few stackoverflow talk about the same idea, but nothing working easily in Angular 11 or easy to use
    • https://stackoverflow.com/questions/62961776/is-it-possible-to-create-an-angular-material-mat-table-component-with-extra-dire
    • https://betterprogramming.pub/angular-material-build-your-own-generic-mattable-a49ba68a375a
  • Tried to copy MatTable and extends CDKTable but
    • _headerRowOutlet was always undefined in my copy

Finally from a more standard way :

  1. Create your own component
  2. It takes a few arguments :
    • functionalName : a functional name for the export. I put it in the filename, nothing to do with the display
    • datasource : not a MatTableDataSource, just an array of object
    • headers : the headers, an array of string, one per column
    • Sort must be at this level... Because the ng-container describing the column contains mat-sort-header for sorting... So we'll pass the the sort to the generic table.
<app-hpa-table [functionalName]="'a comprehensive name for export'" [dataSource]="array of object" [headers]="an array of string" [parentSort]="sort" matSort matSortActive="weight">
  1. A list of column definition. "name" is in the array 'headers'. Element comes from the array of objects.
        <ng-container matColumnDef="name">
            <th mat-header-cell *matHeaderCellDef mat-sort-header> Name </th>
            <td mat-cell *matCellDef="let element"><div class="widget-list-name-column">{{element.name}}</div></td>
        </ng-container>
  1. The typescript part of the parent component
    1. ViewChild for sort should be static
@ViewChild(MatSort, {static: true}) sort: MatSort;
  1. The array of objects should be set in one line (not append object by object) to avoid to many update of the generic table

A bit long, I'll describe the generic component another time and try to make an online example.

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