agent: reload Enterprise configuration (#849)

When the Nomad agent configuration is reloaded the Enterprise license
checker must also be updated in case the Nomad token used to make API
calls changes.

Author: lgfa29

CHANGELOG.md

@@ -5,6 +5,7 @@ IMPROVEMENTS:
 
 BUG FIXES:
  * agent: Fixed a bug that caused a target in dry-run mode to scale when outside of its min/max range [[GH-845](https://github.com/hashicorp/nomad-autoscaler/pull/845)]
+ * agent: Fixed a bug that caused the Enterprise license checker to not be reloaded on `SIGHUP` [[GH-849](https://github.com/hashicorp/nomad-autoscaler/pull/849)]
 
 ## 0.4.1 (January 18, 2024)
 

GNUmakefile

@@ -5,6 +5,7 @@ GIT_COMMIT := $(shell git rev-parse --short HEAD)
 GIT_DIRTY := $(if $(shell git status --porcelain),+CHANGES)
 
 GO_LDFLAGS := "$(GO_LDFLAGS) -X github.com/hashicorp/nomad-autoscaler/version.GitCommit=$(GIT_COMMIT)$(GIT_DIRTY)"
+GO_TAGS := ""
 
 # Attempt to use gotestsum for running tests, otherwise fallback to go test.
 GO_TEST_CMD = $(if $(shell command -v gotestsum 2>/dev/null),gotestsum --,go test)
@@ -67,8 +68,9 @@ pkg/%.zip: pkg/%/nomad-autoscaler ## Build and zip Nomad Autoscaler for GOOS_GOA
 .PHONY: dev
 dev: lint ## Build for the current development version
 	@echo "==> Building autoscaler..."
-	@CGO_ENABLED=0 go build \
+	@CGO_ENABLED=0 GOPROXY=direct go build \
 		-ldflags $(GO_LDFLAGS) \
+		-tags "$(GO_TAGS)" \
 		-o ./bin/nomad-autoscaler
 	@rm -f $(BIN)/nomad-autoscaler && cp ./bin/nomad-autoscaler $(BIN)/
 	@echo "==> Done"
@@ -82,7 +84,8 @@ proto: ## Generate the protocol buffers
 .PHONY: lint
 lint: lint-tools generate-tools hclfmt ## Lint the source code
 	@echo "==> Linting source code..."
-	@golangci-lint run -j 1
+	@GOPROXY=direct \
+	golangci-lint run -j 1 --build-tags "$(GO_TAGS)"
 	@staticcheck ./...
 	@hclogvet .
 	@buf lint --config=./tools/buf/buf.yaml
@@ -129,7 +132,8 @@ check-protobuf: ## Checks the protobuf files are in-sync
 test: ## Test the source code
 	@$(MAKE) -C plugins/test
 	@echo "==> Testing source code..."
-	@$(GO_TEST_CMD) -v -race -cover ./...
+	@GOPROXY=direct \
+    	$(GO_TEST_CMD) -v -race -cover ./... -tags "$(GO_TAGS)"
 	@echo "==> Done"
 
 .PHONY: clean-plugins

agent/agent.go

@@ -39,6 +39,10 @@ type Agent struct {
 	// setting up all clients. It is the result of the Nomad api.DefaultConfig
 	// merged with the user-specified Nomad config.Nomad.
 	nomadCfg *api.Config
+
+	// entReload is used to notify the Enterprise license watcher to reload its
+	// configuration.
+	entReload chan any
 }
 
 func NewAgent(c *config.Agent, configPaths []string, logger hclog.Logger) *Agent {
@@ -47,6 +51,7 @@ func NewAgent(c *config.Agent, configPaths []string, logger hclog.Logger) *Agent
 		config:      c,
 		configPaths: configPaths,
 		nomadCfg:    nomadHelper.MergeDefaultWithAgentConfig(c.Nomad),
+		entReload:   make(chan any),
 	}
 }
 
@@ -83,7 +88,7 @@ func (a *Agent) Run(ctx context.Context) error {
 		a.config.PolicyEval.DeliveryLimit)
 	a.initWorkers(ctx)
 
-	a.initEnt(ctx)
+	a.initEnt(ctx, a.entReload)
 
 	// Launch the eval handler.
 	go a.runEvalHandler(ctx, policyEvalCh)
@@ -210,6 +215,8 @@ func (a *Agent) reload() {
 		os.Exit(1)
 	}
 
+	a.entReload <- struct{}{}
+
 	a.logger.Debug("reloading policy sources")
 	// Set new Nomad client in the Nomad policy source.
 	ps, ok := a.policySources[policy.SourceNameNomad]

agent/agent_oss.go

@@ -8,4 +8,15 @@ package agent
 
 import "context"
 
-func (a *Agent) initEnt(_ context.Context) {}
+func (a *Agent) initEnt(ctx context.Context, reload <-chan any) {
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-reload:
+				continue
+			}
+		}
+	}()
+}