GitLab Duo Workflow

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Status Authors Coach DRIs Owning Stage Created
ongoing DylanGriffith mikolaj_wawrzyniak devops create 2024-05-17

Execution Environment

Executive Summary

The functionality to support Duo Workflow needs to be able to execute arbitrary code which effectively means “untrusted” code. This means that they cannot just run like any other service we deploy and specifically they cannot just run inside the Duo Workflow Service or AI Gateway.

In order to address this the Duo Workflow functionality will be comprised of 2 separate components:

  1. The Duo Workflow Service, which is a Python service we run in our infrastructure. The Workflow Service is built on top of LangGraph.
  2. The Duo Worklow Executor, which is a Go binary that communicates via long running gRPC connection to the Duo Workflow Service and executes the arbtitrary commands. It will be possible for users to run this locally or in CI pipelines.

In our first release we will support 2 execution modes:

  1. Local Executor: which will run commands and edit files locally in a sandboxed Docker container on the developer machine. They will be able to see the files being edited live and it will be interactive
  2. CI Executor: All non-local use-cases of Duo Workflow (for example: issue/epic based workflows) will be triggered by the GitLab UI and will create a CI Pipeline to run the Duo Workflow Executor

Our architecture will also support mixed deployments for self-managed such that some features of Duo Workflow will be available using a cloud-hosted AI Gateway.

Detailed plan

We plan on building this feature set with 3 independent components that can be run in multiple runtimes:

  1. The Duo Workflow Web UI. This will be web UI built into GitLab that manages the creation and interaction of all workflows. There may be many interaction points in the GitLab application but there should be a central workflow UI with reusable components (e.g. Vue components) that could be embedded into our editor extensions
  2. The Duo Workflow Service. This is a Python-based service we deploy with a gRPC API. The only interface to this is the gRPC interface, which is called from the Duo Workflow Executor. Internally, this will use LangGraph to execute the workflows. For reasons why LangGraph was chosen, see this work item. The Workflow Service will not have any persisted state but the state of running workflows will be kept in memory and periodically checkpointed in GitLab. The Workflow Service is built in its own codebase and will have its own deployment but the codebase may be merged with the AI Gateway codebase in the future
  3. The Duo Workflow Executor. This is being written in Go for easy installation in development containers. This component will run in CI jobs or on a user’s local workstation. In the local workstation it will run sandboxed in a Docker container with the working directory optionally mounted by the user for a live pairing experience. It will only be responsible for opening a gRPC connection to Duo Workflow Service and executing the commands it is told to.

The following are important constraints of the architecture:

  1. All state management for workflows will be inside GitLab.
  2. Duo Workflow Service is expected to periodically checkpoint its state in GitLab
  3. Duo Workflow Service in-memory state can be dropped/lost at any time so checkpointing will be the only guaranteed point that can be returned to
  4. If a local Duo Workflow Executor drops the connection, the Duo Workflow Service will checkpoint and shutdown the state as soon as it runs into something where it is waiting on the executor
  5. In order to avoid multiple Duo Workflow Service instances running on the same workflow, the Duo Workflow Service will always acquire a lock with GitLab before it starts running. When it suspends, it will release the lock and similarly there will be a timeout state if it has not checkpointed in the last 60 seconds. GitLab will not accept checkpoints from a timed out run of the Duo Workflow Service.
  6. Each time a Duo Workflow Service resumes a workflow it gets a new ID and this is sent when checkpointing so that GitLab can drop/ignore zombie services running the workflow and inform the zombie service to shutdown.
  7. Code is checkpointed by the executor pushing hidden Git refs to the GitLab instance. This will be happening on the same frequency as other checkpoints.
  8. For local execution Duo Workflows are initiated using the Duo Workflow Executor directly calling Duo Workflow Service
  9. For workflows triggered via the UI that don’t require a Duo Workflow Executor GitLab can call the Duo Workflow Service directly
  10. All API calls from Duo Workflow Service to GitLab that access private data or update data will be authenticated on behalf of the user that created the worklow. Duo Workflow Service should not need privileged access to GitLab

CI pipelines have been chosen as the hosted runtime option for Duo Workflow Executor because it is the only infrastructure we have available today to run untrusted customer workloads with stability, support, security, abuse prevention and a billing model. In the short term for early customers we may rely on the existing compute minutes for CI pipelines but in the long run we may want to deploy dedicated runners and introduce a billing model specific for Duo Workflow.

For many development use cases we expect developers may prefer to run Duo Workflow Executor locally as it can operate on a locally mounted directory and allow the user to more easily watch changes as they happen.

GitLab.com architecture

Duo Workflow Architecture gitlab-com

  1. Initially we focus on running locally and in CI pipelines with all inputs as environment variables
  2. State stored in GitLab so it can be accessed from the web UI and through IDE extensions

With Local (IDE) execution

sequenceDiagram
   participant user as User
   participant ide as IDE
   participant executor as Duo Workflow Executor
   participant gitlab_rails as GitLab Rails
   box AI-gateway service
     participant duo_workflow_service as Duo Workflow Service
     participant ai_gateway as AI Gateway
   end
   participant llm_provider as LLM Provider
   ide->>gitlab_rails: Request AI Gateway JWT using OAuth token or PAT
   ide->>executor: start executor with JWT
   user->>ide: trigger workflow from IDE
   executor->>+duo_workflow_service: Solve this issue (open grpc connection auth'd with AI Gateway JWT)
   duo_workflow_service->>gitlab_rails: Request ai_workflow scoped OAuth token using AI Gateway JWT
   duo_workflow_service->>gitlab_rails: Create the workflow (auth'd with ai_workflow OAuth token)
   duo_workflow_service->>llm_provider: Ask LLM what to do
   llm_provider->>duo_workflow_service: Run rails new my_new_app
   duo_workflow_service->>executor: execute `rails new my_new_app`
   executor->>duo_workflow_service: result `rails new my_new_app`
   duo_workflow_service->>gitlab_rails: Save checkpoint
   duo_workflow_service->>llm_provider: What's next?
   llm_provider->>duo_workflow_service: You're finished
   duo_workflow_service->>gitlab_rails: Save checkpoint and mark completed
   duo_workflow_service->>gitlab_rails: Revoke ai_workflow scoped OAuth token
   deactivate duo_workflow_service
   gitlab_rails->>user: Workflow done!

With Remote (CI pipeline) execution

sequenceDiagram
   participant user as User
   participant gitlab_rails as GitLab Rails
   box CI-Runner
      participant executor as Duo Workflow Executor
   end
   box AI-gateway service
     participant duo_workflow_service as Duo Workflow Service
     participant ai_gateway as AI Gateway
   end
   participant llm_provider as LLM Provider

   user->>gitlab_rails: trigger workflow from Web UI
   gitlab_rails->>executor: start executor (sends AI Gateway JWT with request)
   executor->>+duo_workflow_service: Solve this issue (open grpc connection auth'd with AI Gateway JWT)
   duo_workflow_service->>gitlab_rails: Request ai_workflow scoped OAuth token using AI Gateway JWT
   duo_workflow_service->>gitlab_rails: Create the workflow (auth'd with ai_workflow OAuth token)
   duo_workflow_service->>llm_provider: Ask LLM what to do
   llm_provider->>duo_workflow_service: Run rails new my_new_app
   duo_workflow_service->>executor: execute `rails new my_new_app`
   executor->>duo_workflow_service: result `rails new my_new_app`
   duo_workflow_service->>gitlab_rails: Save checkpoint
   duo_workflow_service->>llm_provider: What's next?
   llm_provider->>duo_workflow_service: You're finished
   duo_workflow_service->>gitlab_rails: Save checkpoint and mark completed
   duo_workflow_service->>gitlab_rails: Revoke ai_workflow scoped OAuth token
   deactivate duo_workflow_service
   gitlab_rails->>user: Workflow done!

Self-managed architecture

With local Duo Workflow Service

When customers are running the Duo Workflow Service locally the architecture will be very similar to GitLab.com . This will also allow them to use whatever customer models they configure in their Duo Workflow Service.

Duo Workflow Self managed full

With cloud Duo Workflow Service

In order to allow self-managed customers to trial and rapidly adopt Duo Workflow without running all Duo Workflow Service components this architecture will supported a mixed deployment mode. In this case we assume that the cloud AI Gateway will not have access to the customers GitLab instance but we can make use of the local executor (on the user’s machine or in a CI runner) to proxy all interactions with GitLab.

Duo Workflow Self managed mixed

Running without the Executor

As described above there are 2 reasons we need the Duo Workflow Executor:

  1. We need a sandboxed environment to safely execute arbitrary commands generated by the AI
  2. We need a path to proxy requests to self-managed GitLab instances that may not be visible to our cloud Duo Workflow Service

But we will have a subset of use cases for Duo Workflow where these conditions will not apply. Specifically we expect to have “non-code” workflows (e.g. review this merge request) where we just need to interact between LLM and GitLab APIs. And if the customer is using GitLab.com or a self-hosted AI Gateway that has access to their GitLab instance then we can safely run all of this inside the Duo Workflow Service making API calls to the GitLab instance.

This architecture unlocks a considerable advantage as we expect the cost of running workloads in CI pipelines is quite high (and indeed wasteful) and the effort to get a local Executor running is also quite high and it may limit the value for simple non-code workflows if these were a requirement. Additionally we get quite significant scaling advantages if we never have to create a CI pipeline to do some of these non-code workflows as starting up a pipeline and keeping it running for the duration of a workflow is a large overhead.

Duo Workflow without executor

We may choose to support this architecture later but it will depend on the following design decisions:

  1. The workflow should know how to call GitLab directly for several API calls and especially checkpointing
  2. Proxying to GitLab via the Executor should be designed as an optional proxy where the Duo Workflow Service constructs the full HTTP request, but under certain configurations, will choose to pass the HTTP request to the executor instead of calling GitLab directly
  3. The Duo Workflow Executor is optional for workflows. The workflow should only suspend when the workflow depends on an executor and one is not present. When the workflow suspends it should know to checkpoint in GitLab before shutting down.
  4. The Duo Workflow Service will need to acquire some kind of “lease” from the GitLab instance while it is running to prevent the possibility of 2 instances of the same workflow running concurrently or to prevent a crashed workflow from being indefinitely locked up and cannot be resumed. Leases should timeout and API calls to checkpoint (or perform other operations) may be rejected if they come from an instance of the workflow with an expired lease.

Data flow

The below diagram shows what happens when the user is triggering workflows from their IDE using a local executor. The architecture will be similar when triggering from the GitLab UI using CI pipelines except that GitLab will start a CI pipeline to create run the Duo Workflow Executor and create the workflow.

sequenceDiagram
   participant user as User
   participant ide as IDE
   participant executor as Duo Workflow Executor
   participant gitlab_rails as GitLab Rails
   participant duo_workflow_service as Duo Workflow Service
   participant llm_provider as LLM Provider
   user->>ide: trigger workflow from IDE
   ide->>executor: start executor
   executor->>+duo_workflow_service: Solve this issue
   duo_workflow_service->>gitlab_rails: Create the workflow
   duo_workflow_service->>llm_provider: Ask LLM what to do
   llm_provider->>duo_workflow_service: Need the file list
   duo_workflow_service->>executor: execute `ls`
   duo_workflow_service->>gitlab_rails: Save checkpoint
   executor->>duo_workflow_service: result `ls`
   duo_workflow_service->>llm_provider: What's next?
   llm_provider->>duo_workflow_service: Here's a patch
   duo_workflow_service->>executor: execute `git apply`
   duo_workflow_service->>gitlab_rails: Save checkpoint
   duo_workflow_service->>executor: execute `poetry run pytest`
   duo_workflow_service->>gitlab_rails: Save checkpoint
   executor->>duo_workflow_service: result `poetry run pytest`
   duo_workflow_service->>llm_provider: fix the tests
   llm_provider->>duo_workflow_service: Here's a patch
   duo_workflow_service->>executor: execute `git apply`
   duo_workflow_service->>gitlab_rails: Save checkpoint
   duo_workflow_service->>executor: execute `poetry run pytest`
   executor->>duo_workflow_service: result `poetry run pytest`
   duo_workflow_service->>executor: Next step?
   executor->>gitlab_rails: Check in & Next step?
   gitlab_rails->>executor: Last step!
   executor->>duo_workflow_service: Done!
   deactivate duo_workflow_service
   gitlab_rails->>user: Workflow done!

CI Pipeline architecture

We don’t want users to have to configure a specific .gitlab-ci.yml in order to support Duo Workflow. In order to avoid this we’ll use the same approach as that used by DAST site validations which dynamically constructs a pipeline configuration in GitLab and triggers the pipeline without using any .gitlab-ci.yml.

CI Pipelines also must be run inside a project. There will be some usecases of Duo Workflow where there is no appropriate project in which to run the pipeline (e.g. bootstrapping a new project). For these workflows we will:

  1. Initially require the user to have a default Workflow project created. It can just be any empty project and we’ll automatically run the pipeline there.
  2. If this proves to be too much setup we’ll automate the creation of a default Duo Workflow project for you
  3. If the UX is poor over time we might abstract the user away from the existence of the Project altogether and make this an implementation detail. This will be considered a last resort because it could be quite a wide impacting change to GitLab as projects are a central part of GitLab.

Considerations for CI Runners and Infrastructure

  1. Our Duo Workflow rollout may involve substantial increases to our CI runner usage
  2. Duo Workflow will likely involve running long running CI pipelines that use very little CPU. Mostly what they will be doing is communicating back and forth with the LLMs and users in a long running gRPC connection.
  3. Users will expect very low latency for CI Runner startup
    1. We should determine if there are ways to have preloaded VMs with our Docker images running ready to start a pipeline when it a workflow is triggered
  4. We likely want a set of CI Runners that are just for Duo Workflow. This may mean enabling the runners to a subset of customers or just using appropriate job labeling/runner matching to only use these runners for Duo Workflow
  5. It might be possible to roll out some Duo Workflow features on our existing runner fleets but we believe there will be enough benefits to invest in segregating these runners.

State checkpointing

The Duo Workflow state will be persisted in GitLab-Rails as the Duo Workflow Service works. There are 2 components to state:

  1. The State object being managed by Langgraph. This includes all prompt history between user and agents and any other metadata created by the LangGraph graph
  2. The working directory where the agent is writing code.
  3. We will have data retention limits on all state. We will use PostgreSQL partitioning to drop old workflow data after some time and we will also drop old Git refs after some time.

We will be persisting the LangGraph state object using APIs in GitLab to persist this state to PostgreSQL as it goes. The API will use similar LangGraph conventions to identify all checkpoints with a thread_ts as implemented in the POC https://gitlab.com/gitlab-org/gitlab/-/merge_requests/153551.

For the current working directory which contains the code the agent has written so far we will store this by pushing hidden Git refs to GitLab for the checkpoint. Each checkpoint will have an associated ref and a checkpoint naming convention (or something stored in PostgreSQL) will allow us to identify the appropriate Git ref for the state checkpoint.

Storing in Git has the advantage that we don’t need to build any new API for storing artifacts and it’s very easy for the user to access the code by just checking out that SHA. It also has huge storage savings where a workflow is working on an existing large project. Ultimately we expect code changes end up being pushed to Git anyway so this is the simplest solution.

Some Duo Workflows do not have an existing project (e.g. bootstrapping a project). Even those workflows will need to be triggered from some project (as explained in the section about CI piplelines). As such we can use the workflow project as a temporary repository to store the snapshots of code generated by the workflow.

Consideration should also be made to cleanup Git refs over time after some workflow expiration period.

Authentication

Duo Workflow requires several authentication flows.

In this section, each connection that requires authentication is listed and the authentication mechanism is discussed.

Duo Workflow Auth

Local Duo Workflow Executor -> Duo Workflow Service

When a Duo Workflow starts, the Duo Workflow Executor must connect to the Duo Workflow Service.

To authenticate this connection:

  1. The IDE will use the OAuth token of Personal Access Token (PAT) that the user generated while setting up the GitLab editor extension.
  2. The IDE uses that token to authenticate a request to a GitLab Rails API endpoint to obtain a short-lived user- and system-scoped JWT.
  3. When the GitLab Rails instance receives this request, it loads its instance-scoped JWT (synced daily from CustomersDot) and contacts the AI gateway to swap this instance token for the above-mentioned user-scoped token (also cryptographically signed)
  4. GitLab Rails returns this JWT to the IDE.
  5. The IDE passes on this JWT to the local Duo Workflow Executor component.
  6. The Duo Workflow Executor uses this JWT to authenticate the Duo Workflow Service gRPC connection.

This flow mimics the token flow that allows IDEs to connect direct to the AI Gateway.

CI Duo Workflow Executor -> Duo Workflow Service

When a Duo Workflow is executed by a CI Runner, the Duo Workflow Executor must connect to the Duo Workflow Service.

A CI Pipeline is created by GitLab, so there is no need to query a GitLab Rails API endpoint to obtain a short-lived user- and system-scoped JWT. Instead, in the process of creating the CI pipeline, GitLab Rails will:

  1. Generate the user-scoped JWT.
  2. Inject the JWT as an environment variable (for example: DUO_WORKFLOW_TOKEN) in the CI pipeline.
  3. The Duo Workflow Executor running inside the CI job uses this environment variable value to authenticate the Duo Workflow Service gRPC connection.

Duo Workflow Service -> GitLab Rails API

Reasons that the Duo Workflow Service must be able to authenticate requests to the GitLab Rails API:

  1. The Duo Workflow Service will need to periodically make requests to GitLab Rails to sync workflow state. This means that the Duo Workflow Service must be able to authenticate these requests.
  2. Duo Workflow may need to make other GitLab Rails API queries to gather context. For example, a Duo Workflow for “solve issue with code” would require an API request to retrieve the issue content.
  3. The end state of a Duo Workflow may take the form of a generated artifact (for example, Git commit or pull request) on the GitLab platform. To generate this artifact, the Duo Workflow Service must be able to make API requests to GitLab Rails.

Requirements for the token used to authenticate requests from the Duo Workflow Service to the GitLab Rails API:

  1. Any artifacts created by a Duo Workflow must be auditable in order to maintain transparency about AI-generated activities on the GitLab platform.
  2. The token’s access level must match the access level of the user who initiated the Workflow to ensure that there is no privilege escalation.
  3. We must have the ability to block read/write for all resources that belong to instances/projects/groups with duo_features_enabled set to false.
  4. Token must be valid for as long as it takes an agent to execute or be refreshable by the Duo Workflow Service. Workflow execution may take several hours.

The JWT that the Workflow Executor uses to authenticate to the Duo Workflow Service could potentially be adapted to also work for this use-case but has some problems:

  1. Need to update GitLab Rails to accept this type of token for API authentication.
  2. JWTs are not revocable; what if we need to cut off an agent’s access?
  3. Need to build token rotation. How would the Duo Workflow Service authenticate an API request to generate a new token if the old JWT is already expired?

For these reasons, OAuth is a better protocol for this use-case. OAuth tokens:

  1. Are only valid for 2 hours.
  2. Can be revoked.
  3. Have a built-in refresh flow.
  4. Are an established authentication pattern for federating access between services.

To use OAuth, we will:

  1. Create a new token scope called ai_workflows (related issue)
  2. When the IDE requests the Duo Workflow Service User JWT from GitLab Rails, we will also generate and return an OAuth token with the ai_workflows scope.
  3. Duo Workflow executor will send that OAuth token, along with the base_url of the GitLab Rails instance, as metadata when the Duo Workflow Service when the gRPC connection is opened.
  4. The Duo Workflow Service will use the OAuth token for any GitLab Rails API Requests to read or write data for a Workflow.

Options we’ve considered and pros/cons

Delegate only unsafe execution to local/CI pipelines

This was the option we chose. It attempts to keep as much of the functionality as possible in services we run while delegating the unsafe execution to Duo Workflow Executor which can run locally or in CI pipelines.

Pros:

  1. Running the infrastructure ourselves gives us more control over the versions being rolled out
  2. There is less dependencies the user needs to install for local usage
  3. It offers a rapid onboarding experience for self-managed customers to try Duo Workflow without deploying any new GitLab components

Cons

  1. We need to deploy and maintain new infrastructure which has different scaling characteristics to other services we run duo to long running execution

Run it locally

Pros:

  1. This keeps developers in their local environment where most of them work
  2. Compute is absorbed by the local developer so they don’t have to worry about being billed per minute
  3. Low latency for user interaction especially where the user needs to review/edit code while the agent is working

Cons:

  1. There are more risks running it locally unless you have an isolated development environment as commands have full access to your computer. This can be mitigated by UX that limits what commands the agent can run without user confirmation.
  2. This approach will require some local developer setup and may not be suited to tasks that users are expecting to kick off from the web UI (e.g. issue/epic planning)

CI pipelines (on CI runners)

See https://gitlab.com/gitlab-org/gitlab/-/issues/457959 for a POC and investigation.

Pros:

  1. CI pipelines are the only pre-configured infrastructure we have that can run untrusted workflows
  2. We have an established billing model for CI minutes

Cons:

  1. CI pipelines are slow to start up and this might mean that iteration and incremental AI development might be slow if the pipelines need to be restarted while timing out waiting for user input
  2. CI minutes will need to be consumed while the agent is awaiting for user input. This will likely require a timeout mechanism and as such if the user returns we’ll need to restart a new pipeline when they give input
  3. CI pipelines run in a difficult to access environment (ie. you cannot SSH it or introspect it live) and as such it may make it difficult for users to interact with code that is being built out live in front of them without
  4. CI pipelines require there to be some project to run in. This is not likely something we can overcome but we may be able to simplify the setup process by automatically creating you a “workflow project” for your workflow pipelines to run in
  5. When we implement non-code workflows (e.g. reviewing MRs) there is no need for an isolated compute environment but we’ll still be forcing customers to use compute minutes. We’ve seen this is not a good experience in other cases like X-Ray reports

GitLab workspaces (remote development)

See https://gitlab.com/gitlab-org/gitlab/-/issues/458339 for a POC and investigation.

Pros:

  1. This has the fastest iteration cycle as the agent is working locally in your development environment and can interact with you and you can even see and edit the same files live as them
  2. Customers can run it on their own infrastructure and this gives them control over efficient resource usage

Cons:

  1. Today we only support customers bringing their own infrastructure (K8s cluster) and this means that the barrier to getting started is to bring your own K8s cluster and this is a fairly significant effort
  2. If we wanted to build out infrastructure on GitLab.com to save customers having to bring their own K8s cluster this would be a fairly large effort from a security and infrastructure perspective. It’s possible but to deal with all the complexities of security, abuse and billing would require many teams involvement in both initial development and sustained maintenance.

Security

Threat modeling

See https://gitlab.com/gitlab-com/gl-security/product-security/appsec/threat-models/-/issues/46.

Security considerations for local execution

Local execution presents the highest value opportunity for developers but also comes with the greatest risk that a bug or mistake from an LLM could lead to causing significant harm to a user’s local development environment or compromise confidential information.

Some examples of risks:

  1. An AI that can make honest but significant mistakes
  2. An AI that might sometimes be adversarial
  3. The AI gateway serving the LLM responses may be compromised which would then allow shell access to all users of this tool

Sandboxing Duo Workflow Executor

One proposal here to mitigate risks would be to use some form of sandboxing where the Duo Workflow Executor is only able to run inside of an unprivileged Docker container. Such a solution would need to:

  1. Mount the local working directory into the container so it is still editing the files the user is working on in the host
  2. Install all development dependencies the user or agent would need to run the application and tests

The above option may also make use of Dev Containers.

User confirmation for commands

Another option for limiting the risk is to require the user to confirm every command the agent executes before it runs the command. We will likely be implementing this as an option anyway but given the desire for efficient development of larger workflows it might limit the efficiency of the tool if it needs to execute a lot of commands to finish a task.

We may also consider a hybrid approach where there a set of user-defined allowlisted commands (e.g. ls and cat) which allow the agent to read and learn about a project without the user needing to confirm. This approach may not solve all needs though where the user may want to allowlist commands like rspec which then effectively still allow for arbitrary code execution as the agent can put whatever they want in the spec file.

Duo Workflow UI

The Duo Workflow UI will need to be available at least in the following places:

  1. In GitLab Rails web UI
  2. In our editor extensions

The fact that we’ll need multiple UIs and also as described above we have multiple execution environments for Duo Workflow Executor have led to the following decisions.

How do we package and run the local web UI

We will build the majority of data access related to our local IDE UI into the GitLab Language Server to maximize re-use across all our editor extensions. We will also employ a mix of webviews rendered in the IDE and served by the LSP as well as native IDE UI elements. Where it doesn’t considerably limit our user experience we’ll opt to build the interface into a web page served from the LSP and then rendered in the IDE as a web view because this again maximises re-use across all our editor extensions.

How does the web UI reflect the current state live

The Duo Workflow Service will persist it’s state frequently to the main GitLab Rails application. There will be GraphQL subscriptions for streaming updates about a workflow. The UI will consume these GraphQL apis and update the UI as updates stream in.

Given that the user may be running the Duo Workflow Executor locally which may be seeing some of the state as it happens it might be reasonable to want to just live render the in-memory state of the running workflow process. We may choose this option deliberately for latency reasons, but we need to be careful to architect the frontend and Duo Workflow Executor as completely decoupled because they will not always be running together. For example users may trigger a workflow locally which runs in GitLab CI or they may be using the web UI to interact with and re-run a workflow that was initiated locally.

As such we will generally prefer not to have direct interaction between the UI and Executor, but instead all communication should be happening via GitLab. Any exceptions to this might be considered case by case, but we’ll need clear API boundaries to allow the functionality to easily be changed to consume from GitLab for the reasons described.

States

UI states are going to be driven by the server to ensure consistency and no race condition between UI state changes and API responses. This will simplify keeping data and action in sync. All possible workflow states can be seen in the WorflowStatusEnum.

New

The first UI state is when the user needs to submit a goal. This is only a client-side concern and does not translate to any server-side state.

Not started / created

After starting a workflow with a user defined goal, a Workflow is created which translates to LangGraph creating an empty checkpoint. On the API side, the workflow will be created with the NOT_STARTED state, which means that a goal has been sent, but not plan has been returned from LangGraph yet. This is the point where the client needs to start subscribing to DuoWorkflowEvent.

Planning

Once in planning, we need to start streaming Workflow responses back to the client. We are getting the checkpoint field from the DuoWorkflowEvent subscrition which is a JsonString that represents LangGraph raw response. For the first iteration, the client will rely solely on this JSON string to get all new data and drive the UI, which mean that we needto parse the JSON and account for possible parsing errors. It also mean having a very tight coupling between the UI and LangGraph, so this parsing should be abstracted away in its own functionality so that it can be easily removed.

Important: For the first iteration, there is no way to stop or pause a Workflow and this mean that once the goal has been submitted, we will not render any button or UI interactions. The UI will “move on its own” where for example, once the PLANNING phase is over, we will automatically open the EXECUTING panel and start rendering the right information. Users do not need to confirm or interact and the Workflow should reach its final state on its own.

Executing

What should drive the progress bar is the subscription to workflowEventsUpdated and getting checkpoints streamed back to the client so that we know what progress was made in the execution and what step is currently being executed. This is where the user watches steps and progress being made.

Completed

Once all of the events are done streaming, the API should return the COMPLETED state and we can show the finished screen.

Future iterations

As of writing this documentation, there are no PENDING state as this is currently not planned for the first version of the Workflow, but it’s worth keeping in mind for future iterations. This mean that the user cannot pause execution and/or we cannot have users interact during execution. The Workflow will eventually be interactable and these interactions should be added to this documentation.

Checkpoints

Checkpoints are built on the server-side and serve as a way to resume execution from certain points. There are some interactions between checkpoints and the UI that are foundational to the experience. Checkpoint should:

  • Be streamed to the client for real time update
  • Contain the current state
  • Contain the current step being executed

Ability to load workflow from checkpoints

If a Workflow cannot reach the COMPLETED state before it stops executing, then the user should have the ability to start again only from the latest checkpoint. From a UI perspective, this mean that we need to support multiple workflow because otherwise we cannot know which workflow currently exists. This should be doable by fetching duoWorkflowWorkflows and rendering all existing workflows. For the IDEs, this mean rendering existing workflows in the sidebar.

Then when selecting a workflow, fetch information about the current workflow with how to fetch an existing workflow. Here is what should happen based on states:

  • NONE: The user will not have any state preserved, meaning that any goal typed out, but not submitted will not be kept.
  • NOT STARTED: resends the initial request to generate a plan and shows the loading state
  • PLANNING: loading the workflow should show existing proposed plan.
  • EXECUTING: Resume from the right step. In future iterations. the Workflow should probably be “stopped/paused” and then the user could resume. For this added functionality, we need the PENDING state to exists.
  • COMPLETED: Show the result of the workflow after its completion.

Duo Workflow Agent’s tools

Duo Workflow agents are, in a simplified view, a pair of: prompt and LLM. By this definition, agents on their own are not able to interact with the outside world, which significantly limits the scope of work that can be automated. To overcome this limitation, agents are being equipped with tools.

Tools are functions that agents can invoke using the function calling LLM feature. These functions perform different actions on behalf of the agent. For example, an agent might be equipped with a tool (function) that executes bash commands like ls or cat and returns the result of those bash commands back to the agent.

The breadth of the tool set available to agents defines the scope of work that can be automated. Therefore, to set up the Duo Workflow feature for success, it will be required to deliver a broad and exhaustive tool set.

Foreseen tools include:

  1. Tools to execute bash commands via the Duo Workflow Executor
  2. Tools to manipulate files (including reading and writing to files)
  3. Tools to manipulate Git VCS
  4. Tools to integrate with the GitLab HTTP API

The fact that the Duo Workflow Service is going to require Git and GitLab API tools entails that the Duo Workflow Service must have the ability to establish an SSH connection and make HTTP requests to the GitLab instance. This ability can be granted directly to the Duo Workflow Service or can be provided via the Duo Workflow Executor if a direct connection between the Duo Workflow Service and a GitLab instance is not possible due to a firewall or network partition.

Milestones

  1. All the components implemented and communicating correctly with only a trivial workflow implemented
  2. Checkpointing code as well as LangGraph state
  3. Workflow locking in GitLab to ensure only 1 concurrent instance of a workflow
  4. Add more workflows and tools
  5. Ability to resume a workflow

POC - Demos

  1. POC: Solve issue (internal only)
  2. POC: Duo Workflow in Workspaces (internal only)
  3. POC: Autograph using Docker Executor (internal only)
  4. POC: Duo Workflows in CI pipelines with timeout and restart (internal only)
Last modified August 23, 2024: Ensure frontmatter is consistent (e47101dc)