DEVPROD-8413 Make ps logging configurable #9750

malikchaya2 · 2026-01-28T22:18:03Z

DEVPROD-8413

Description

This PR introduces two things:

The option to specify the ps command at a project, task and bv level (similar to exec_timeout_secs). This is described in more detail in the docs change in this PR.
A feature flag that disables default logging. When set to true, we will no longer run ps automatically and it will only run if specified (as described above).

Testing

This was tested on staging:

with ps logging disabled and nothing specified - this correctly runs the ps stats collector with no ps.
with custom ps logging - it correctly runs ps aux which was specified with ps: "ps aux" at the task level.

UI PR

1336

ablack12 · 2026-02-03T14:08:55Z

agent/agent.go

+		opts.expansionsAndVars.Expansions.Put("ps", "ps")
+	}
+	// Project and task settings can override the default.
+	if opts.project.Ps != "" {


nit: Can we either make this PS, or elsewhere have the flag be Ps?

ablack12 · 2026-02-03T14:10:54Z

model/project.go

 	if bvt.Stepback == nil {
 		bvt.Stepback = pt.Stepback
 	}
+	if bvt.Ps == nil && pt.Ps != "" {


Do we want the task version of this to also be a pointer, such that it can override behavior? (Not sure if that actually happens, seems consistent with the bool flags though)

ablack12 · 2026-02-03T14:12:10Z

config_serviceflags.go

 			debugSpawnHostDisabledKey:          c.DebugSpawnHostDisabled,
 			s3LifecycleSyncDisabledKey:         c.S3LifecycleSyncDisabled,
 			useGitForGitHubFilesDisabledKey:    c.UseGitForGitHubFilesDisabled,
+			psLoggingDisabledKey:               c.PSLoggingDisabled,


If we aren't putting this on the admin page, then we probably don't want to set this here, since we'll just override whatever is set if we make any other changes. (If its temporary it could be okay to just set via DB)

I already added it to graphql (in this PR) and I plan to open a UI pr to add it to the admin page. It won't add too much work and it'll make the migration easier.

ablack12 · 2026-02-03T14:13:30Z

agent/agent.go

 		"uptime",
 		"df -h",
-		"${ps|ps}",
+		// The empty fallback is needed to make ps opt-in so that if thee ps expansion is not set,


nit: thee -> the

ablack12 · 2026-02-03T14:14:31Z

agent/agent.go

+		opts.expansionsAndVars.Expansions.Put("ps", opts.project.Ps)
+	}
+	if projectTask := opts.project.FindProjectTask(opts.task.DisplayName); projectTask != nil && projectTask.Ps != "" {
+		opts.expansionsAndVars.Expansions.Put("ps", projectTask.Ps)


I think if we're using expansions for this feature, it would also make sense to add this to the Default Expansions section.

quick update: After some more testing and investigation into our current configurations (I can explain more offline) I decided to refactor this to not use expansions because I want to stop defaulting to distro level ps expansions unless specifically specified with ps: ${ps}. I'm working on that refactor and will re-request review once it's ready.

ablack12 · 2026-02-03T14:14:43Z

agent/agent.go

 	// parameters, so load them from the project.
+	// If PSLoggingDisabled is false, default to "ps" command.
+	if !a.opts.SetupData.PSLoggingDisabled {
+		opts.expansionsAndVars.Expansions.Put("ps", "ps")


can the "ps" expansion be a constant? Also perhaps this section can be modularized out to a helper.

ablack12 · 2026-02-03T14:17:26Z

docs/Project-Configuration/Project-Configuration-Files.md

+```yaml
+tasks:
+  - name: task_with_custom_ps
+    ps: "ps -o pid,tty,time,comm,args" # Custom ps command for this task


sorry if i missed where we did this, but can we add these to the list of available task and variant fields in the docs as well?

We don't have a consolidated list of task fields (I can create a ticket to add it if you'd like).

The Build Variants Fields section is for fields that can be set directly on the build variant itself (like name, display_name, run_on, etc). This can only be set on the BuildVariantTaskUnit, so I instead added a mention to the tasks field in that list.

Ah gotcha. What's the logic for not having this set at the variant level, out of curiosity, just not needed, or bc we want to reduce how often we're doing overrides?

love the big new example also!

Just to reduce how often we're doing overrides, we can add it later if there is interest.

ablack12 · 2026-02-05T22:06:49Z

agent/task_context.go

+	}
+
+	// For backward compatibility: when PSLoggingDisabled=false, fall back to ps expansion.
+	// This allows distro/build variant expansions to work for existing projects.


wait sorry just to clarify my understanding -- when we do disable ps logging, does that mean we won't be accepting distro-level expansions anymore?

Correct, once it's disabled, there will be no more automatic ps logging, including not accepting distro-level expansions. Users will have to set ps to ${ps | ps} to get what the default is now.

ablack12 · 2026-02-05T22:07:21Z

model/project_parser.go

 			GitTagOnly:      pt.GitTagOnly,
 			Stepback:        pt.Stepback,
 			MustHaveResults: pt.MustHaveResults,
+			Ps:              pt.Ps,


nit: can we also change this to be PS to be consistent with Project?

add custom ps

f314287

malikchaya2 force-pushed the ps branch from 0bc112e to f314287 Compare January 28, 2026 22:20

malikchaya2 requested a review from a team January 28, 2026 22:20

ablack12 requested changes Feb 3, 2026

View reviewed changes

malikchaya2 added 4 commits February 3, 2026 11:37

cr

ff2a6e5

Merge branch 'main' into ps

9263540

gqlgen

9d0a42c

fix verify-merge-function-update

ab5a013

malikchaya2 mentioned this pull request Feb 3, 2026

DEVPROD-8413 Add psLoggingDisabled flag evergreen-ci/ui#1336

Merged

malikchaya2 added 4 commits February 3, 2026 15:48

fix priority and add more clarification to docs

ca54309

don't use expansions

031f347

better docs

3289093

cleanup

801923a

malikchaya2 requested a review from ablack12 February 4, 2026 17:21

ablack12 approved these changes Feb 5, 2026

View reviewed changes

malikchaya2 and others added 4 commits February 6, 2026 12:09

Ps --> PS

da7a9b0

Merge branch 'main' into ps

4ea5355

Merge branch 'main' into ps

b39c49b

empty commit

0871c23

malikchaya2 merged commit 98ebc16 into evergreen-ci:main Feb 9, 2026
12 checks passed

malikchaya2 deleted the ps branch February 9, 2026 19:34

DEVPROD-8413 Make ps logging configurable #9750

DEVPROD-8413 Make ps logging configurable #9750

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malikchaya2 commented Jan 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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malikchaya2 commented Jan 28, 2026 •

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