feat: command flag to override parallel pool size

server/events/apply_command_runner.go

@@ -158,7 +158,11 @@ func (a *ApplyCommandRunner) Run(ctx *command.Context, cmd *CommentCommand) {
 	var result command.Result
 	if a.isParallelEnabled(projectCmds) {
 		ctx.Log.Info("Running applies in parallel")
-		result = runProjectCmdsParallelGroups(ctx, projectCmds, a.prjCmdRunner.Apply, a.parallelPoolSize)
+		parallelPoolSize := a.parallelPoolSize
+		if cmd.ParallelPoolSize > 0 {
+			parallelPoolSize = cmd.ParallelPoolSize
+		}
+		result = runProjectCmdsParallelGroups(ctx, projectCmds, a.prjCmdRunner.Apply, parallelPoolSize)
 	} else {
 		result = runProjectCmds(projectCmds, a.prjCmdRunner.Apply)
 	}

server/events/comment_parser.go

@@ -47,6 +47,8 @@ const (
 	verboseFlagShort             = ""
 	clearPolicyApprovalFlagLong  = "clear-policy-approval"
 	clearPolicyApprovalFlagShort = ""
+	ParallelPoolSizeFlagLong     = "parallel-pool-size"
+	ParallelPoolSizeFlagShort    = "P"
 )
 
 // multiLineRegex is used to ignore multi-line comments since those aren't valid
@@ -232,6 +234,7 @@ func (e *CommentParser) Parse(rawComment string, vcsHost models.VCSHostType) Com
 	var verbose bool
 	var autoMergeDisabled bool
 	var autoMergeMethod string
+	var parallelPoolSize int
 	var flagSet *pflag.FlagSet
 	var name command.Name
 
@@ -245,6 +248,7 @@ func (e *CommentParser) Parse(rawComment string, vcsHost models.VCSHostType) Com
 		flagSet.StringVarP(&dir, dirFlagLong, dirFlagShort, "", "Which directory to run plan in relative to root of repo, ex. 'child/dir'.")
 		flagSet.StringVarP(&project, projectFlagLong, projectFlagShort, "", "Which project to run plan for. Refers to the name of the project configured in a repo config file. Cannot be used at same time as workspace or dir flags.")
 		flagSet.BoolVarP(&verbose, verboseFlagLong, verboseFlagShort, false, "Append Atlantis log to comment.")
+		flagSet.IntVarP(&parallelPoolSize, ParallelPoolSizeFlagLong, ParallelPoolSizeFlagShort, 0, "Override default parallel pool size for this command")
 	case command.Apply.String():
 		name = command.Apply
 		flagSet = pflag.NewFlagSet(command.Apply.String(), pflag.ContinueOnError)
@@ -255,6 +259,7 @@ func (e *CommentParser) Parse(rawComment string, vcsHost models.VCSHostType) Com
 		flagSet.BoolVarP(&autoMergeDisabled, autoMergeDisabledFlagLong, autoMergeDisabledFlagShort, false, "Disable automerge after apply.")
 		flagSet.StringVarP(&autoMergeMethod, autoMergeMethodFlagLong, autoMergeMethodFlagShort, "", "Specifies the merge method for the VCS if automerge is enabled. (Currently only implemented for GitHub)")
 		flagSet.BoolVarP(&verbose, verboseFlagLong, verboseFlagShort, false, "Append Atlantis log to comment.")
+		flagSet.IntVarP(&parallelPoolSize, ParallelPoolSizeFlagLong, ParallelPoolSizeFlagShort, 0, "Override default parallel pool size for this command")
 	case command.ApprovePolicies.String():
 		name = command.ApprovePolicies
 		flagSet = pflag.NewFlagSet(command.ApprovePolicies.String(), pflag.ContinueOnError)
@@ -335,8 +340,13 @@ func (e *CommentParser) Parse(rawComment string, vcsHost models.VCSHostType) Com
 		}
 	}
 
+	if parallelPoolSize < 0 {
+		err := fmt.Sprintf("invalid value for --%s: %d, must be >= 0", ParallelPoolSizeFlagLong, parallelPoolSize)
+		return CommentParseResult{CommentResponse: e.errMarkdown(err, cmd, flagSet)}
+	}
+
 	return CommentParseResult{
-		Command: NewCommentCommand(dir, extraArgs, name, subName, verbose, autoMergeDisabled, autoMergeMethod, workspace, project, policySet, clearPolicyApproval),
+		Command: NewCommentCommand(dir, extraArgs, name, subName, verbose, autoMergeDisabled, autoMergeMethod, workspace, project, parallelPoolSize, policySet, clearPolicyApproval),
 	}
 }
 

server/events/comment_parser_test.go

@@ -750,6 +750,78 @@ func TestParse_Parsing(t *testing.T) {
 	}
 }
 
+func TestParse_ParallelPoolSize(t *testing.T) {
+	cases := []struct {
+		command         command.Name
+		flags           string
+		expParallelSize int
+		expError        string
+	}{
+		// Test flag works for plan/apply
+		{
+			command:         command.Plan,
+			flags:           "-P 5",
+			expParallelSize: 5,
+		},
+		{
+			command:         command.Plan,
+			flags:           "--parallel-pool-size 10",
+			expParallelSize: 10,
+		},
+		{
+			command:         command.Apply,
+			flags:           "-P 3",
+			expParallelSize: 3,
+		},
+		{
+			command:         command.Apply,
+			flags:           "--parallel-pool-size 8",
+			expParallelSize: 8,
+		},
+		// Test flag is ignored for other commands
+		{
+			command:  command.ApprovePolicies,
+			flags:    "-P 5",
+			expError: fmt.Sprintf("```\nError: unknown shorthand flag: 'P' in -P.\n%s```", ApprovePolicyUsage),
+		},
+		{
+			command:  command.ApprovePolicies,
+			flags:    "-p project --parallel-pool-size 5",
+			expError: fmt.Sprintf("```\nError: unknown flag: --parallel-pool-size.\n%s```", ApprovePolicyUsage),
+		},
+		// // Test invalid values
+		{
+			command:  command.Plan,
+			flags:    "-P fail",
+			expError: fmt.Sprintf("```\nError: invalid argument \"fail\" for \"-P, --parallel-pool-size\" flag: strconv.ParseInt: parsing \"fail\": invalid syntax.\n%s```", PlanUsage),
+		},
+		{
+			command:  command.Apply,
+			flags:    "--parallel-pool-size -1",
+			expError: fmt.Sprintf("```\nError: invalid value for --parallel-pool-size: -1, must be >= 0.\n%s```", ApplyUsage),
+		},
+	}
+
+	for _, test := range cases {
+		comment := fmt.Sprintf("atlantis %s %s", test.command.String(), test.flags)
+		t.Run(comment, func(t *testing.T) {
+			r := commentParser.Parse(comment, models.Github)
+
+			if test.expError != "" {
+				Equals(t, test.expError, r.CommentResponse)
+				return
+			}
+
+			Assert(t, r.CommentResponse == "",
+				"expected no error but got %q for comment %q",
+				r.CommentResponse, comment)
+			Assert(t, test.expParallelSize == r.Command.ParallelPoolSize,
+				"exp parallel pool size to equal %v but was %v for comment %q",
+				test.expParallelSize, r.Command.ParallelPoolSize, comment)
+		})
+	}
+}
+
 func TestBuildPlanApplyVersionComment(t *testing.T) {
 	cases := []struct {
 		repoRelDir        string
@@ -1048,13 +1120,14 @@ func TestParse_VCSUsername(t *testing.T) {
 }
 
 var PlanUsage = `Usage of plan:
-  -d, --dir string         Which directory to run plan in relative to root of repo,
-                           ex. 'child/dir'.
-  -p, --project string     Which project to run plan for. Refers to the name of the
-                           project configured in a repo config file. Cannot be used
-                           at same time as workspace or dir flags.
-      --verbose            Append Atlantis log to comment.
-  -w, --workspace string   Switch to this Terraform workspace before planning.
+  -d, --dir string               Which directory to run plan in relative to root of
+                                 repo, ex. 'child/dir'.
+  -P, --parallel-pool-size int   Override default parallel pool size for this command
+  -p, --project string           Which project to run plan for. Refers to the name
+                                 of the project configured in a repo config file.
+                                 Cannot be used at same time as workspace or dir flags.
+      --verbose                  Append Atlantis log to comment.
+  -w, --workspace string         Switch to this Terraform workspace before planning.
 `
 
 var ApplyUsage = `Usage of apply:
@@ -1064,6 +1137,7 @@ var ApplyUsage = `Usage of apply:
                                    for GitHub)
   -d, --dir string                 Apply the plan for this directory, relative to
                                    root of repo, ex. 'child/dir'.
+  -P, --parallel-pool-size int     Override default parallel pool size for this command
   -p, --project string             Apply the plan for this project. Refers to the
                                    name of the project configured in a repo config
                                    file. Cannot be used at same time as workspace or

server/events/event_parser.go

@@ -140,6 +140,8 @@ type CommentCommand struct {
 	// project specified in an atlantis.yaml file.
 	// If empty then the comment specified no project.
 	ProjectName string
+	// ParallelPoolSize allows changing parallel pool size for a plan/apply specific command.
+	ParallelPoolSize int
 	// PolicySet is the name of a policy set to run an approval on.
 	PolicySet string
 	// ClearPolicyApproval is true if approvals should be cleared out for specified policies.
@@ -184,7 +186,7 @@ func (c CommentCommand) String() string {
 }
 
 // NewCommentCommand constructs a CommentCommand, setting all missing fields to defaults.
-func NewCommentCommand(repoRelDir string, flags []string, name command.Name, subName string, verbose, autoMergeDisabled bool, autoMergeMethod string, workspace string, project string, policySet string, clearPolicyApproval bool) *CommentCommand {
+func NewCommentCommand(repoRelDir string, flags []string, name command.Name, subName string, verbose, autoMergeDisabled bool, autoMergeMethod string, workspace string, project string, parallelPoolSize int, policySet string, clearPolicyApproval bool) *CommentCommand {
 	// If repoRelDir was empty we want to keep it that way to indicate that it
 	// wasn't specified in the comment.
 	if repoRelDir != "" {
@@ -203,6 +205,7 @@ func NewCommentCommand(repoRelDir string, flags []string, name command.Name, sub
 		AutoMergeDisabled:   autoMergeDisabled,
 		AutoMergeMethod:     autoMergeMethod,
 		ProjectName:         project,
+		ParallelPoolSize:    parallelPoolSize,
 		PolicySet:           policySet,
 		ClearPolicyApproval: clearPolicyApproval,
 	}

server/events/event_parser_test.go

@@ -751,14 +751,14 @@ func TestNewCommand_CleansDir(t *testing.T) {
 
 	for _, c := range cases {
 		t.Run(c.RepoRelDir, func(t *testing.T) {
-			cmd := events.NewCommentCommand(c.RepoRelDir, nil, command.Plan, "", false, false, "", "workspace", "", "", false)
+			cmd := events.NewCommentCommand(c.RepoRelDir, nil, command.Plan, "", false, false, "", "workspace", "", 0, "", false)
 			Equals(t, c.ExpDir, cmd.RepoRelDir)
 		})
 	}
 }
 
 func TestNewCommand_EmptyDirWorkspaceProject(t *testing.T) {
-	cmd := events.NewCommentCommand("", nil, command.Plan, "", false, false, "", "", "", "", false)
+	cmd := events.NewCommentCommand("", nil, command.Plan, "", false, false, "", "", "", 0, "", false)
 	Equals(t, events.CommentCommand{
 		RepoRelDir:  "",
 		Flags:       nil,
@@ -770,15 +770,16 @@ func TestNewCommand_EmptyDirWorkspaceProject(t *testing.T) {
 }
 
 func TestNewCommand_AllFieldsSet(t *testing.T) {
-	cmd := events.NewCommentCommand("dir", []string{"a", "b"}, command.Plan, "", true, false, "", "workspace", "project", "policyset", false)
+	cmd := events.NewCommentCommand("dir", []string{"a", "b"}, command.Plan, "", true, false, "", "workspace", "project", 5, "policyset", false)
 	Equals(t, events.CommentCommand{
-		Workspace:   "workspace",
-		RepoRelDir:  "dir",
-		Verbose:     true,
-		Flags:       []string{"a", "b"},
-		Name:        command.Plan,
-		ProjectName: "project",
-		PolicySet:   "policyset",
+		Workspace:        "workspace",
+		RepoRelDir:       "dir",
+		Verbose:          true,
+		Flags:            []string{"a", "b"},
+		Name:             command.Plan,
+		ProjectName:      "project",
+		PolicySet:        "policyset",
+		ParallelPoolSize: 5,
 	}, *cmd)
 }
 

server/events/plan_command_runner.go

@@ -249,7 +249,11 @@ func (p *PlanCommandRunner) run(ctx *command.Context, cmd *CommentCommand) {
 	var result command.Result
 	if p.isParallelEnabled(projectCmds) {
 		ctx.Log.Info("Running plans in parallel")
-		result = runProjectCmdsParallelGroups(ctx, projectCmds, p.prjCmdRunner.Plan, p.parallelPoolSize)
+		parallelPoolSize := p.parallelPoolSize
+		if cmd.ParallelPoolSize > 0 {
+			parallelPoolSize = cmd.ParallelPoolSize
+		}
+		result = runProjectCmdsParallelGroups(ctx, projectCmds, p.prjCmdRunner.Plan, parallelPoolSize)
 	} else {
 		result = runProjectCmds(projectCmds, p.prjCmdRunner.Plan)
 	}