1888293 - Connection to agent is not re-established if agent is restarted or started after Nightly

Status: VERIFIED FIXED

(Firefox :: Data Loss Prevention, enhancement)

Description

[Haik Aftandilian [:haik]]

If the DLP agent is started after Nightly starts, the connection is not established. This includes if the agent was running when Nightly launched and is then restarted.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:handyman, could you have a look please?

For more information, please visit BugBot documentation.

Comment 2

[David Parks [:handyman]]

This seems fine but I thought the plan for this was to do nothing? The user would get DLP blocks for everything, along with a message about the agent connection having failed, until the browser was restarted.

Comment 4

[Greg Stoll :gstoll]

Attachment: Bug 1888293 part 1 - add IsRejected() method to MozPromise r=#xpcom-reviewers!

This method is used in part 2 to avoid recreating a MozPromise that
hasn't been resolved or rejected.
This change also includes some linting.

Comment 5

[Greg Stoll :gstoll]

Attachment: Bug 1888293 part 1 - make connecting to agent threadsafe, add helper CallClientWithRetry() method r=#dlp-reviewers!

The CallClientWithRetry() method encapsulates the logic for attempting
to reconnect to the client if either:

• the mCaClientPromise was rejected, so last time we failed to connect
  to the client
• the mCaClientPromise was resolved, but calling the client returns an
  error, indicating that in the meantime the DLP agent has been terminated
  (and possibly started again)

Comment 6

[Greg Stoll :gstoll]

Attachment: Bug 1888293 part 2 - make anything that uses the client go through CallClientWithRetry() r=#dlp-reviewers!

After this change the only uses of mCaClientPromise should be in creating
the client or in CallClientWithRetry(), so everything that uses the client
will go through the retry logic if the client is not connected.

Comment 7

[Greg Stoll :gstoll]

Attachment: Bug 1888293 part 3 - add gtests for reconnecting to DLP agent r=#dlp-reviewers!

I also added a few tests for GetDiagnosticInfo().

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1e50a6eb0b4b
part 1 - make connecting to agent threadsafe, add helper CallClientWithRetry() method r=dlp-reviewers,handyman
https://hg.mozilla.org/integration/autoland/rev/7f757483382e
part 2 - make anything that uses the client go through CallClientWithRetry() r=dlp-reviewers,handyman
https://hg.mozilla.org/integration/autoland/rev/9550881f6afa
part 3 - add gtests for reconnecting to DLP agent r=dlp-reviewers,handyman

Comment 9

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/1e50a6eb0b4b
https://hg.mozilla.org/mozilla-central/rev/7f757483382e
https://hg.mozilla.org/mozilla-central/rev/9550881f6afa

Comment 10

[Alexandru Trif, Desktop Test Engineering [:atrif]]

Hello! We have verified that the DLP Agent connection can be established with Firefox 137.0a1 (2025-02-20) on Windows 10x64 in the following scenarios:

• start Firefox, then start the DLP agent - test case C2749248
• stop the DLP Agent while Firefox is running then restart the DLP agent - test case C2929598
  Note that the Browser connected log output is displayed in CMD only after performing clipboard paste/ drag and drop action or printing if the agent is started/ restarted while Firefox is running.

Please let us know if the verification and test cases are correct or if anything else should be added here. Thank you!

Comment 11

[Greg Stoll :gstoll]

Great, thanks!

Those tests look good. I would recommend adding a step in both test cases to go to about:support and verify that the "Content Analysis (DLP)" section is correct, specifically:

• "Active" should be true as long as the policy is set up correctly, even if the agent isn't running
• "Connected to Agent" is true if the last time a DLP request was made it was successfully sent to the agent. (so if the agent is terminated, then a request is made from Firefox that fails, then the agent is restarted, it is OK if this value is false before another request is done)
• "Agent Path" should be the path on disk of the agent, if it is connected

It would be nice to do this:

• in C2749248 between steps 1 and 2 (before the new agent is started) and after step 3
• in C2929598 between steps 3 and 4 (after the "unable to connect to the DLP agent" message) and after step 5.

Comment 12

[Greg Stoll :gstoll]

(oh, and the "Browser connected" message not showing up until a request is sent to the agent is expected - we only try to reestablish the connection when we need to send a request, thanks!)

Comment 13

[Alexandru Trif, Desktop Test Engineering [:atrif]]

Thank you, Greg! I have updated the test cases and verified that everything works as expected on Windows10 x64 with 137.0a1 (2025-02-23).