Merge pull request #1177 from dmattia/dmattia/concurrency_flag

Added configurable parallelism pool size

cmd/server.go

@@ -68,6 +68,7 @@ const (
 	GitlabWebhookSecretFlag    = "gitlab-webhook-secret" // nolint: gosec
 	HidePrevPlanComments       = "hide-prev-plan-comments"
 	LogLevelFlag               = "log-level"
+	ParallelPoolSize           = "parallel-pool-size"
 	AllowDraftPRs              = "allow-draft-prs"
 	PortFlag                   = "port"
 	RepoConfigFlag             = "repo-config"
@@ -101,6 +102,7 @@ const (
 	DefaultGHHostname       = "github.com"
 	DefaultGitlabHostname   = "gitlab.com"
 	DefaultLogLevel         = "info"
+	DefaultParallelPoolSize = 15
 	DefaultPort             = 4141
 	DefaultTFDownloadURL    = "https://releases.hashicorp.com"
 	DefaultTFEHostname      = "app.terraform.io"
@@ -331,6 +333,10 @@ var boolFlags = map[string]boolFlag{
 	},
 }
 var intFlags = map[string]intFlag{
+	ParallelPoolSize: {
+		description:  "Max size of the wait group that runs parallel plans and applies (if enabled).",
+		defaultValue: DefaultParallelPoolSize,
+	},
 	PortFlag: {
 		description:  "Port to bind to.",
 		defaultValue: DefaultPort,
@@ -553,6 +559,9 @@ func (s *ServerCmd) setDefaults(c *server.UserConfig) {
 	if c.LogLevel == "" {
 		c.LogLevel = DefaultLogLevel
 	}
+	if c.ParallelPoolSize == 0 {
+		c.ParallelPoolSize = DefaultParallelPoolSize
+	}
 	if c.Port == 0 {
 		c.Port = DefaultPort
 	}

cmd/server_test.go

@@ -80,6 +80,7 @@ var testFlags = map[string]interface{}{
 	LogLevelFlag:               "debug",
 	AllowDraftPRs:              true,
 	PortFlag:                   8181,
+	ParallelPoolSize:           100,
 	RepoAllowlistFlag:          "github.com/runatlantis/atlantis",
 	RequireApprovalFlag:        true,
 	RequireMergeableFlag:       true,

runatlantis.io/docs/server-configuration.md

@@ -335,6 +335,12 @@ Values are chosen in this order:
   ```
   Log level. Defaults to `info`.
 
+* ### `--parallel-pool-size`
+  ```bash
+  atlantis server --parallel-pool-size=100
+  ```
+  Max size of the wait group that runs parallel plans and applies (if enabled). Defaults to `15`
+
 * ### `--port`
   ```bash
   atlantis server --port=8080

server/events/command_runner.go

@@ -82,6 +82,9 @@ type DefaultCommandRunner struct {
 	Logger                   logging.SimpleLogging
 	// AllowForkPRs controls whether we operate on pull requests from forks.
 	AllowForkPRs bool
+	// ParallelPoolSize controls the size of the wait group used to run
+	// parallel plans and applies (if enabled).
+	ParallelPoolSize int
 	// AllowForkPRsFlag is the name of the flag that controls fork PR's. We use
 	// this in our error message back to the user on a forked PR so they know
 	// how to enable this functionality.
@@ -402,7 +405,7 @@ func (c *DefaultCommandRunner) runProjectCmdsParallel(cmds []models.ProjectComma
 	var results []models.ProjectResult
 	mux := &sync.Mutex{}
 
-	wg := sizedwaitgroup.New(15)
+	wg := sizedwaitgroup.New(c.ParallelPoolSize)
 	for _, pCmd := range cmds {
 		pCmd := pCmd
 		var execute func()

server/server.go

@@ -370,6 +370,7 @@ func NewServer(userConfig UserConfig, config Config) (*Server, error) {
 		SilenceVCSStatusNoPlans:  userConfig.SilenceVCSStatusNoPlans,
 		DisableApplyAll:          userConfig.DisableApplyAll,
 		DisableAutoplan:          userConfig.DisableAutoplan,
+		ParallelPoolSize:         userConfig.ParallelPoolSize,
 		ProjectCommandBuilder: &events.DefaultProjectCommandBuilder{
 			ParserValidator:    validator,
 			ProjectFinder:      &events.DefaultProjectFinder{},

server/user_config.go

@@ -38,6 +38,7 @@ type UserConfig struct {
 	GitlabWebhookSecret        string `mapstructure:"gitlab-webhook-secret"`
 	HidePrevPlanComments       bool   `mapstructure:"hide-prev-plan-comments"`
 	LogLevel                   string `mapstructure:"log-level"`
+	ParallelPoolSize           int    `mapstructure:"parallel-pool-size"`
 	PlanDrafts                 bool   `mapstructure:"allow-draft-prs"`
 	Port                       int    `mapstructure:"port"`
 	RepoConfig                 string `mapstructure:"repo-config"`