Add transport implementation for agent

Makefile

@@ -27,6 +27,7 @@ KUSTOMIZE 		:= $(GO) run sigs.k8s.io/kustomize/kustomize/v4@v4.5
 SETUP_ENVTEST   := $(GO) run sigs.k8s.io/controller-runtime/tools/setup-envtest@v0.0.0-20220304125252-9ee63fc65a97
 GOLANGCI_LINT	:= $(GO) run github.com/golangci/golangci-lint/cmd/golangci-lint@v1.52
 YAMLFMT			:= $(GO) run github.com/google/yamlfmt/cmd/yamlfmt@v0.6
+MOQ				:= $(GO) run github.com/matryer/moq@v0.3
 
 # Installed tools
 PROTOC_GEN_GO_GRPC 	:= google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.2
@@ -94,11 +95,18 @@ e2e-test: ## Run e2e tests
 	$(SETUP_ENVTEST) use
 	source <($(SETUP_ENVTEST) use -p env) && $(GO) test -v ./internal/e2e/... -tags=e2e
 
+mocks:
+	$(MOQ) -fmt goimpots -rm -out ./internal/proto/workflow/v2/mock.go ./internal/proto/workflow/v2 WorkflowServiceClient WorkflowService_GetWorkflowsClient
+	$(MOQ) -fmt goimports -rm -out ./internal/agent/transport/mock.go ./internal/agent/transport WorkflowHandler
+	$(MOQ) -fmt goimports -rm -out ./internal/agent/mock.go ./internal/agent Transport ContainerRuntime
+	$(MOQ) -fmt goimports -rm -out ./internal/agent/event/mock.go ./internal/agent/event Recorder
+
 .PHONY: generate-proto
 generate-proto: buf.gen.yaml buf.lock $(shell git ls-files '**/*.proto') _protoc
 	$(BUF) mod update
 	$(BUF) generate
 	$(GOFUMPT) -w internal/proto/*.pb.*
+	$(GOFUMPT) -w internal/proto/workflow/v2/*.pb.*
 
 .PHONY: generate
 generate: generate-proto generate-go generate-manifests ## Generate code, manifests etc.
@@ -241,4 +249,4 @@ yamllint: $(YAMLLINT_BIN)
 .PHONY: _protoc ## Install all required tools for use with this Makefile.
 _protoc:
 	GOBIN=$${PWD}/bin $(GO) install $(PROTOC_GEN_GO)
-	GOBIN=$${PWD}/bin $(GO) install $(PROTOC_GEN_GO_GRPC)
+	GOBIN=$${PWD}/bin $(GO) install $(PROTOC_GEN_GO_GRPC)

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/go-logr/zerologr v1.2.3
 	github.com/google/go-cmp v0.5.9
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
+	github.com/kr/pretty v0.3.1
 	github.com/onsi/ginkgo/v2 v2.11.0
 	github.com/onsi/gomega v1.27.8
 	github.com/opencontainers/image-spec v1.1.0-rc.3
@@ -78,6 +79,7 @@ require (
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/kr/text v0.2.0 // indirect
 	github.com/magiconair/properties v1.8.7 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mattn/go-colorable v0.1.12 // indirect
@@ -94,6 +96,7 @@ require (
 	github.com/prometheus/client_model v0.4.0 // indirect
 	github.com/prometheus/common v0.42.0 // indirect
 	github.com/prometheus/procfs v0.10.1 // indirect
+	github.com/rogpeppe/go-internal v1.10.0 // indirect
 	github.com/spf13/afero v1.9.5 // indirect
 	github.com/spf13/cast v1.5.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect

go.sum

@@ -600,6 +600,7 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pretty v0.2.0/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/pty v1.1.5/go.mod h1:9r2w37qlBe7rQ6e1fg1S/9xpWHSnaqNdHD3WcMdbPDA=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
@@ -692,6 +693,7 @@ github.com/pelletier/go-toml/v2 v2.0.8/go.mod h1:vuYfssBdrU2XDZ9bYydBu6t+6a6PYNc
 github.com/peterbourgon/diskv v2.0.1+incompatible/go.mod h1:uqqh8zWWbv1HBMNONnaR/tNboyR3/BZd58JJSHlUSCU=
 github.com/pierrec/lz4 v1.0.2-0.20190131084431-473cd7ce01a1/go.mod h1:3/3N9NVKO0jef7pBehbT1qWhCMrIgbYNnFAZCqQ5LRc=
 github.com/pierrec/lz4 v2.6.1+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
@@ -740,7 +742,9 @@ github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475/go.mod h1:bCqn
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=
 github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
+github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
+github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/rs/xid v1.4.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
 github.com/rs/zerolog v1.29.1 h1:cO+d60CHkknCbvzEWxP0S9K6KqyTjrCNUy1LdQLCGPc=
 github.com/rs/zerolog v1.29.1/go.mod h1:Le6ESbR7hc+DP6Lt1THiV8CQSdkkNrd3R0XbEgp3ZBU=

internal/agent/agent.go

@@ -3,6 +3,7 @@ package agent
 import (
 	"context"
 	"errors"
+	"sync"
 
 	"github.com/go-logr/logr"
 	"github.com/tinkerbell/tink/internal/agent/event"
@@ -27,7 +28,12 @@ type Agent struct {
 	// Runtime is the container runtime used to execute workflow actions.
 	Runtime ContainerRuntime
 
+	// sem ensure we handle a single workflow at a time.
 	sem chan struct{}
+
+	// executionContext tracks the currently executing workflow.
+	executionContext *executionContext
+	mtx              sync.RWMutex
 }
 
 // Start finalizes the Agent configuration and starts the configured Transport so it is ready
@@ -43,40 +49,94 @@ func (agent *Agent) Start(ctx context.Context) error {
 	}
 
 	if agent.Runtime == nil {
-		//nolint:stylecheck // Specifying field on data structure
+		//nolint:stylecheck // Runtime is a field of agent.
 		return errors.New("Runtime field must be set before calling Start()")
 	}
 
+	if agent.Log.GetSink() == nil {
+		agent.Log = logr.Discard()
+	}
+
 	agent.Log = agent.Log.WithValues("agent_id", agent.ID)
 
 	// Initialize the semaphore and add a resource to it ensuring we can run 1 workflow at a time.
 	agent.sem = make(chan struct{}, 1)
 	agent.sem <- struct{}{}
 
-	agent.Log.Info("Starting agent")
 	return agent.Transport.Start(ctx, agent.ID, agent)
 }
 
 // HandleWorkflow satisfies transport.
-func (agent *Agent) HandleWorkflow(ctx context.Context, wflw workflow.Workflow, events event.Recorder) error {
-	// sem isn't protected by a synchronization data structure so this is technically invoking
-	// undefined behavior - consider this a best effort to ensuring Start() has been called.
+func (agent *Agent) HandleWorkflow(ctx context.Context, wflw workflow.Workflow, events event.Recorder) {
 	if agent.sem == nil {
-		return errors.New("agent must have Start() called before calling HandleWorkflow()")
+		agent.Log.Info("Agent must have Start() called before calling HandleWorkflow()")
 	}
 
 	select {
 	case <-agent.sem:
-		// Replenish the semaphore on exit so we can pick up another workflow.
-		defer func() { agent.sem <- struct{}{} }()
-		return agent.run(ctx, wflw, events)
+		// Ensure we configure the current workflow and cancellation func before we launch the
+		// goroutine to avoid a race with CancelWorkflow.
+		agent.mtx.Lock()
+		defer agent.mtx.Unlock()
+
+		ctx, cancel := context.WithCancel(ctx)
+		agent.executionContext = &executionContext{
+			Workflow: wflw,
+			Cancel:   cancel,
+		}
+
+		go func() {
+			// Replenish the semaphore on exit so we can pick up another workflow.
+			defer func() { agent.sem <- struct{}{} }()
+
+			agent.run(ctx, wflw, events)
+
+			// Nilify the execution context after running so cancellation requests are ignored.
+			agent.mtx.Lock()
+			defer agent.mtx.Unlock()
+			agent.executionContext = nil
+		}()
 
 	default:
+		log := agent.Log.WithValues("workflow_id", wflw.ID)
+
 		reject := event.WorkflowRejected{
 			ID:      wflw.ID,
 			Message: "workflow already in progress",
 		}
-		events.RecordEvent(ctx, reject)
-		return nil
+
+		if err := events.RecordEvent(ctx, reject); err != nil {
+			log.Error(err, "Failed to record workflow rejection event")
+			return
+		}
+
+		log.Info("Workflow already executing; dropping request")
+	}
+}
+
+func (agent *Agent) CancelWorkflow(workflowID string) {
+	agent.mtx.RLock()
+	defer agent.mtx.RUnlock()
+
+	if agent.executionContext == nil {
+		agent.Log.Info("No workflow running; ignoring cancellation request", "workflow_id", workflowID)
+		return
 	}
+
+	if agent.executionContext.Workflow.ID != workflowID {
+		agent.Log.Info(
+			"Incorrect workflow ID in cancellation request; ignoring cancellation request",
+			"workflow_id", workflowID,
+			"running_workflow_id", agent.executionContext.Workflow.ID,
+		)
+		return
+	}
+
+	agent.Log.Info("Cancel workflow", "workflow_id", workflowID)
+	agent.executionContext.Cancel()
+}
+
+type executionContext struct {
+	Workflow workflow.Workflow
+	Cancel   context.CancelFunc
 }