Use of LicenseManager with FlexLM

Question

I am developing a plug-in for a third-party application which requires to use a System.LicenseProvider.

The License File itself is FlexLM generated.

so I have:

[LicenseProvider(typeof(LicFileLicenseProvider))]
public class MyLicensedModule
{
    protected System.ComponentModel.License thisLicense;
    protected ModuleFlexFeature thisfeature;

    public bool LicenseCheck()
    {
        bool isLicensed = LicenseManager.IsLicensed(typeof(ModuleFlexFeature)); //returns TRUE
        if(thisFeature==null) thisFeature = new ModuleFlexFeature();
        thisLicense = LicenseManager.Validate(typeof(ModuleFlexFeature),thisFeature);
        //no thrown exception
        return (thisLicense != null); //thisLicense is always null
    }

    public void Dispose()
    {
        if (thisLicense!=null)
        {
            thisLicense.Dispose();
            thisLicense = null;
        }
    }
}

(+ other irrelevant methods), using:

internal class ModuleFlexFeature
{
    public ModuleFlexFeature() { }
    public string FeatureName { get { return "myFlexLMFeature"; } }
    public float FeatureVersion { get { return 2016.0f; } }
}

Using the LMTOOLS by Flexera, I can get the License Server Status (I am running on 7507@mypcname, 0 out of 1 license for myFlexLMFeature is used).

Then I can add 7507@mypcname in the extra servers to be used by the third party app, but:

isLicensed returns true (expected)
LicenseManager.Validate() does not throw exception (expected)
thisLicense is null (not expected)

I've tried to use

LicenseManager.IsValid(typeof(ModuleFlexFeature),new ModuleFlexFeature(), out thisLicense);

but both have similar results (code seems to work but thisLicense is null)

Am I doing anything wrong ? is LicenseManager compatible with FlexLM ? or is there a bug on the third-party app which runs my plug-in (somehow does not connect to the license server properly)? How to check?

Thanks

score 1 · Answer 1 · edited Jun 20 '20 at 09:12

OK, After some more investigation:

You cannot use a LicFileProvider to read FlexLMFiles

You have to create your own LicenseProvider and implement getLicense. To do this, you have to know where the file is / may be, and use lmutil. So first, you need to check if a license is available.

Inspired from this previous question, I have been able to get the following code to check if a license is valid or not (and detect, when several lm servers are used, which one to use):

//get the potential file candidates
string file = Environment.GetEnvironmentVariable("LM_LICENSE_FILE");
List<string> candidates = new List<string>(file.Split(';'));
foreach (string filecan in candidates)
{
    //read the lm stats for this
    string args = "lmstat -f " + MyFeatureName + " -c " + file;
    ProcessStartInfo info = new ProcessStartInfo(@"lmutil.exe", args);
    Process lmutil = Process.Start(info);
    string output = lmutil.StandardOutput.ReadToEnd();

    //now get the line
    string matchPattern = @"Users of (\w+):.*Total of (\d+) license.*Total of (\d+) license";
    MatchCollection matches = Regex.Matches(output, matchPattern);
    foreach(Match m in matches)
    {
        //are only returned: m.Succes = true and m.Groups[1].Value = MyFeatureName
        int value;
        int total = Int32.TryParse(m.Groups[2].Value, out value) ? value : 0;
        int used = Int32.TryParse(m.Groups[3].Value, out value) ? value : 0;
        if (total - used > 0) return true;
    }
}
return false;

This works fine... BUT this does not generate a license (this only checks if I can reasonably hope for one or not).

I've investigated lmborrow but it does not seem to generate a token either. Do you have any idea?

Use of LicenseManager with FlexLM

1 Answers1