Refactor Nomad policy parsing and add tests

CHANGELOG.md

@@ -1,5 +1,8 @@
 ## UNRELEASED
 
+__BACKWARDS INCOMPATIBILITIES:__
+ * agent: configuration `scan_interval` renamed to `default_evaluation_interval` [[GH-114](https://github.com/hashicorp/nomad-autoscaler/pull/114)]
+
 FEATURES:
  * agent: allow policies to specify `evaluation_interval` [[GH-30](https://github.com/hashicorp/nomad-autoscaler/pull/30)]
 

agent/agent.go

@@ -54,7 +54,10 @@ func (a *Agent) Run(ctx context.Context) error {
 	a.healthServer = healthServer
 	go a.healthServer.run()
 
-	source := nomadpolicy.NewNomadSource(a.logger, a.nomadClient)
+	sourceConfig := &nomadpolicy.SourceConfig{
+		DefaultEvaluationInterval: a.config.DefaultEvaluationInterval,
+	}
+	source := nomadpolicy.NewNomadSource(a.logger, a.nomadClient, sourceConfig)
 	manager := policy.NewManager(a.logger, source, a.pluginManager)
 
 	policyEvalCh := make(chan *policy.Evaluation, 10)

agent/config/config.go

@@ -35,10 +35,10 @@ type Agent struct {
 	// PluginDir is the directory that holds the autoscaler plugin binaries.
 	PluginDir string `hcl:"plugin_dir,optional"`
 
-	// ScanInterval is the time duration interval at which the autoscaler runs
-	// evaluations.
-	ScanInterval    time.Duration
-	ScanIntervalHCL string `hcl:"scan_interval,optional" json:"-"`
+	// DefaultEvaluationInterval is the time duration interval used when
+	// `evaluation_interval` is not defined in a policy.
+	DefaultEvaluationInterval    time.Duration
+	DefaultEvaluationIntervalHCL string `hcl:"default_evaluation_interval,optional" json:"-"`
 
 	// HTTP is the configuration used to setup the HTTP health server.
 	HTTP *HTTP `hcl:"http,block"`
@@ -124,9 +124,9 @@ const (
 	// defaultHTTPBindPort is the default port used for the HTTP health server.
 	defaultHTTPBindPort = 8080
 
-	// defaultScanInterval is the default value for the ScaInterval in nano
-	// seconds.
-	defaultScanInterval = time.Duration(10000000000)
+	// defaultEvaluationInterval is the default value for the
+	// DefaultEvaluationInterval in nano seconds.
+	defaultEvaluationInterval = time.Duration(10000000000)
 
 	// defaultPluginDirSuffix is the suffix appended to the PWD when building
 	// the PluginDir default value.
@@ -152,9 +152,9 @@ func Default() (*Agent, error) {
 	}
 
 	return &Agent{
-		LogLevel:     defaultLogLevel,
-		PluginDir:    pwd + defaultPluginDirSuffix,
-		ScanInterval: defaultScanInterval,
+		LogLevel:                  defaultLogLevel,
+		PluginDir:                 pwd + defaultPluginDirSuffix,
+		DefaultEvaluationInterval: defaultEvaluationInterval,
 		HTTP: &HTTP{
 			BindAddress: defaultHTTPBindAddress,
 			BindPort:    defaultHTTPBindPort,
@@ -181,8 +181,8 @@ func (a *Agent) Merge(b *Agent) *Agent {
 	if b.PluginDir != "" {
 		result.PluginDir = b.PluginDir
 	}
-	if b.ScanInterval != 0 {
-		result.ScanInterval = b.ScanInterval
+	if b.DefaultEvaluationInterval != 0 {
+		result.DefaultEvaluationInterval = b.DefaultEvaluationInterval
 	}
 
 	if b.HTTP != nil {
@@ -349,12 +349,12 @@ func parseFile(file string, cfg *Agent) error {
 		return err
 	}
 
-	if cfg.ScanIntervalHCL != "" {
-		d, err := time.ParseDuration(cfg.ScanIntervalHCL)
+	if cfg.DefaultEvaluationIntervalHCL != "" {
+		d, err := time.ParseDuration(cfg.DefaultEvaluationIntervalHCL)
 		if err != nil {
 			return err
 		}
-		cfg.ScanInterval = d
+		cfg.DefaultEvaluationInterval = d
 	}
 	return nil
 }

agent/config/config_test.go

@@ -18,7 +18,7 @@ func Test_Default(t *testing.T) {
 	assert.False(t, def.LogJson)
 	assert.Equal(t, def.LogLevel, "info")
 	assert.True(t, strings.HasSuffix(def.PluginDir, "/plugins"))
-	assert.Equal(t, def.ScanInterval, time.Duration(10000000000))
+	assert.Equal(t, def.DefaultEvaluationInterval, time.Duration(10000000000))
 	assert.Equal(t, def.Nomad.Address, "http://127.0.0.1:4646")
 	assert.Equal(t, "127.0.0.1", def.HTTP.BindAddress)
 	assert.Equal(t, 8080, def.HTTP.BindPort)
@@ -31,8 +31,8 @@ func TestAgent_Merge(t *testing.T) {
 	assert.Nil(t, err)
 
 	cfg1 := &Agent{
-		PluginDir:    "/opt/nomad-autoscaler/plugins",
-		ScanInterval: 5000000000,
+		PluginDir:                 "/opt/nomad-autoscaler/plugins",
+		DefaultEvaluationInterval: 5000000000,
 		HTTP: &HTTP{
 			BindAddress: "scaler.nomad",
 		},
@@ -49,10 +49,10 @@ func TestAgent_Merge(t *testing.T) {
 	}
 
 	cfg2 := &Agent{
-		LogLevel:     "trace",
-		LogJson:      true,
-		PluginDir:    "/var/lib/nomad-autoscaler/plugins",
-		ScanInterval: 10000000000,
+		LogLevel:                  "trace",
+		LogJson:                   true,
+		PluginDir:                 "/var/lib/nomad-autoscaler/plugins",
+		DefaultEvaluationInterval: 10000000000,
 		HTTP: &HTTP{
 			BindPort: 4646,
 		},
@@ -90,10 +90,10 @@ func TestAgent_Merge(t *testing.T) {
 	}
 
 	expectedResult := &Agent{
-		LogLevel:     "trace",
-		LogJson:      true,
-		PluginDir:    "/var/lib/nomad-autoscaler/plugins",
-		ScanInterval: 10000000000,
+		LogLevel:                  "trace",
+		LogJson:                   true,
+		PluginDir:                 "/var/lib/nomad-autoscaler/plugins",
+		DefaultEvaluationInterval: 10000000000,
 		HTTP: &HTTP{
 			BindAddress: "scaler.nomad",
 			BindPort:    4646,
@@ -149,7 +149,7 @@ func TestAgent_Merge(t *testing.T) {
 	assert.Equal(t, expectedResult.LogLevel, actualResult.LogLevel)
 	assert.Equal(t, expectedResult.Nomad, actualResult.Nomad)
 	assert.Equal(t, expectedResult.PluginDir, actualResult.PluginDir)
-	assert.Equal(t, expectedResult.ScanInterval, actualResult.ScanInterval)
+	assert.Equal(t, expectedResult.DefaultEvaluationInterval, actualResult.DefaultEvaluationInterval)
 	assert.ElementsMatch(t, expectedResult.APMs, actualResult.APMs)
 	assert.ElementsMatch(t, expectedResult.Targets, actualResult.Targets)
 	assert.ElementsMatch(t, expectedResult.Strategies, actualResult.Strategies)
@@ -181,11 +181,11 @@ func TestAgent_parseFile(t *testing.T) {
 	// Write some valid content, and ensure this is read and parsed.
 	cfg := &Agent{}
 
-	if _, err := fh.WriteString("scan_interval = \"10s\"\nplugin_dir = \"/opt/nomad-autoscaler/plugins\""); err != nil {
+	if _, err := fh.WriteString("default_evaluation_interval = \"10s\"\nplugin_dir = \"/opt/nomad-autoscaler/plugins\""); err != nil {
 		t.Fatalf("err: %s", err)
 	}
 	assert.Nil(t, parseFile(fh.Name(), cfg))
-	assert.Equal(t, time.Duration(10000000000), cfg.ScanInterval)
+	assert.Equal(t, time.Duration(10000000000), cfg.DefaultEvaluationInterval)
 	assert.Equal(t, "/opt/nomad-autoscaler/plugins", cfg.PluginDir)
 }
 
@@ -198,13 +198,13 @@ func TestConfig_Load(t *testing.T) {
 	assert.Nil(t, err)
 	defer os.Remove(fh.Name())
 
-	_, err = fh.WriteString("scan_interval = \"10s\"")
+	_, err = fh.WriteString("default_evaluation_interval = \"10s\"")
 	assert.Nil(t, err)
 
 	// Works on a config file
 	cfg, err := Load(fh.Name())
 	assert.Nil(t, err)
-	assert.Equal(t, time.Duration(10000000000), cfg.ScanInterval)
+	assert.Equal(t, time.Duration(10000000000), cfg.DefaultEvaluationInterval)
 
 	dir, err := ioutil.TempDir("", "nomad-autoscaler")
 	assert.Nil(t, err)
@@ -234,7 +234,7 @@ func TestAgent_loadDir(t *testing.T) {
 	assert.Equal(t, config, &Agent{})
 
 	file1 := filepath.Join(dir, "config1.hcl")
-	assert.Nil(t, ioutil.WriteFile(file1, []byte("scan_interval = \"10s\""), 0600))
+	assert.Nil(t, ioutil.WriteFile(file1, []byte("default_evaluation_interval = \"10s\""), 0600))
 
 	file2 := filepath.Join(dir, "config2.hcl")
 	assert.Nil(t, ioutil.WriteFile(file2, []byte("plugin_dir = \"/opt/nomad-autoscaler/plugins\""), 0600))
@@ -252,7 +252,7 @@ func TestAgent_loadDir(t *testing.T) {
 	// We should now be able to load as all the configs are valid.
 	cfg, err := loadDir(dir)
 	assert.Nil(t, err)
-	assert.Equal(t, time.Duration(10000000000), cfg.ScanInterval)
+	assert.Equal(t, time.Duration(10000000000), cfg.DefaultEvaluationInterval)
 	assert.Equal(t, "/opt/nomad-autoscaler/plugins", cfg.PluginDir)
 }
 

command/agent.go

@@ -104,7 +104,7 @@ Nomad Options:
 
   -nomad-skip-verify
     Do not verify TLS certificates. This is strongly discouraged.
-  
+
 `
 	return strings.TrimSpace(helpText)
 }
@@ -165,7 +165,7 @@ func (c *AgentCommand) readConfig() *config.Agent {
 	flags.BoolVar(&cmdConfig.LogJson, "log-json", false, "")
 	flags.StringVar(&cmdConfig.PluginDir, "plugin-dir", "", "")
 	flags.Var((flaghelper.FuncDurationVar)(func(d time.Duration) error {
-		cmdConfig.ScanInterval = d
+		cmdConfig.DefaultEvaluationInterval = d
 		return nil
 	}), "scan-interval", "")
 

docs/agent/README.md

@@ -39,7 +39,7 @@ As each file is processed, its contents are merged into the existing configurati
  * `log_level` `(string: "INFO")` -  Specify the verbosity level of Nomad Autoscaler's logs. Valid values include `DEBUG`, `INFO`, and `WARN`, in decreasing order of verbosity.
  * `log_json` `(bool: false)` - Output logs in a JSON format.
  * `plugin_dir` `(string: "./plugins")` - The plugin directory used to discover Nomad Autoscaler plugins.
- * `scan_interval` `(duration: "10s")` - The time to wait between Nomad Autoscaler evaluations.
+ * `default_evaluation_interval` `(duration: "10s")` - The default time to use when a policy doesn't specify an `evaluation_interval`.
 
 ## `http` Block
 The `http` block configures the Nomad Autoscaler's HTTP health endpoint.