feat(lb): add support for configuring backend servers max connections

docs/resources/lb_backend.md

@@ -62,6 +62,8 @@ The following arguments are supported:
 e.g. 'failover-website.s3-website.fr-par.scw.cloud' if your bucket website URL is 'https://failover-website.s3-website.fr-par.scw.cloud/'.
 - `ssl_bridging`                - (Default: `false`) Enables SSL between load balancer and backend servers.
 - `ignore_ssl_server_verify`    - (Default: `false`) Specifies whether the Load Balancer should check the backend server’s certificate before initiating a connection.
+- `max_connections`             - (Optional) Maximum number of connections allowed per backend server.
+- `timeout_queue`               - (Optional) Maximum time for a request to be left pending in queue when `max_connections` is reached. (e.g.: `1s`)
 
 ### Health Check arguments
 

go.mod

@@ -16,7 +16,7 @@ require (
 	github.com/nats-io/jwt/v2 v2.4.1
 	github.com/nats-io/nats.go v1.26.0
 	github.com/robfig/cron/v3 v3.0.1
-	github.com/scaleway/scaleway-sdk-go v1.0.0-beta.17.0.20230619154501-6a12f2ddaa47
+	github.com/scaleway/scaleway-sdk-go v1.0.0-beta.17.0.20230626132518-b0dfa1defaaf
 	github.com/stretchr/testify v1.8.4
 )
 

go.sum

@@ -253,8 +253,8 @@ github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:
 github.com/robfig/cron/v3 v3.0.1 h1:WdRxkvbJztn8LMz/QEvLN5sBU+xKpSqwwUO1Pjr4qDs=
 github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzGIFLtro=
 github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
-github.com/scaleway/scaleway-sdk-go v1.0.0-beta.17.0.20230619154501-6a12f2ddaa47 h1:eGARFgFhRDgxFF6QwimHe+MV21xhuPKLPNhJyML3JkA=
-github.com/scaleway/scaleway-sdk-go v1.0.0-beta.17.0.20230619154501-6a12f2ddaa47/go.mod h1:fCa7OJZ/9DRTnOKmxvT6pn+LPWUptQAmHF/SBJUGEcg=
+github.com/scaleway/scaleway-sdk-go v1.0.0-beta.17.0.20230626132518-b0dfa1defaaf h1:df06kcC2caUTghLW6aTSyL3GUeM79BPvbtMyng187aE=
+github.com/scaleway/scaleway-sdk-go v1.0.0-beta.17.0.20230626132518-b0dfa1defaaf/go.mod h1:fCa7OJZ/9DRTnOKmxvT6pn+LPWUptQAmHF/SBJUGEcg=
 github.com/sergi/go-diff v1.1.0/go.mod h1:STckp+ISIX8hZLjrqAeVduY0gWCT9IjLuqbuNXdaHfM=
 github.com/sergi/go-diff v1.2.0 h1:XU+rvMAioB0UC3q1MFrIQy4Vo5/4VsRDQQXHsEya6xQ=
 github.com/shopspring/decimal v1.2.0/go.mod h1:DKyhrW/HYNuLGql+MJL6WCR6knT2jwCFRcu2hWCYk4o=

scaleway/resource_lb_backend.go

@@ -2,6 +2,8 @@ package scaleway
 
 import (
 	"context"
+	"math"
+	"time"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
@@ -274,6 +276,18 @@ E.g. 'failover-website.s3-website.fr-par.scw.cloud' if your bucket website URL i
 				Optional:    true,
 				Default:     false,
 			},
+			"max_connections": {
+				Type:         schema.TypeInt,
+				Optional:     true,
+				ValidateFunc: validation.IntBetween(0, math.MaxInt32),
+				Description:  "Maximum number of connections allowed per backend server",
+			},
+			"timeout_queue": {
+				Type:         schema.TypeString,
+				Optional:     true,
+				ValidateFunc: validateDuration(),
+				Description:  "Maximum time (in seconds) for a request to be left pending in queue when `max_connections` is reached",
+			},
 		},
 	}
 }
@@ -352,6 +366,17 @@ func resourceScalewayLbBackendCreate(ctx context.Context, d *schema.ResourceData
 		IgnoreSslServerVerify: expandBoolPtr(getBool(d, "ignore_ssl_server_verify")),
 	}
 
+	if maxConn, ok := d.GetOk("max_connections"); ok {
+		createReq.MaxConnections = expandInt32Ptr(maxConn)
+	}
+	if timeoutQueue, ok := d.GetOk("timeout_queue"); ok {
+		timeout, err := time.ParseDuration(timeoutQueue.(string))
+		if err != nil {
+			return diag.FromErr(err)
+		}
+		createReq.TimeoutQueue = &scw.Duration{Seconds: int64(timeout.Seconds())}
+	}
+
 	// deprecated attribute
 	createReq.SendProxyV2 = expandBoolPtr(getBool(d, "send_proxy_v2"))
 
@@ -416,6 +441,11 @@ func resourceScalewayLbBackendRead(ctx context.Context, d *schema.ResourceData,
 	_ = d.Set("failover_host", backend.FailoverHost)
 	_ = d.Set("ssl_bridging", flattenBoolPtr(backend.SslBridging))
 	_ = d.Set("ignore_ssl_server_verify", flattenBoolPtr(backend.IgnoreSslServerVerify))
+	_ = d.Set("max_connections", flattenInt32Ptr(backend.MaxConnections))
+
+	if backend.TimeoutQueue != nil {
+		_ = d.Set("timeout_queue", flattenDuration(backend.TimeoutQueue.ToTimeDuration()))
+	}
 
 	_, err = waitForLB(ctx, lbAPI, zone, backend.LB.ID, d.Timeout(schema.TimeoutRead))
 	if err != nil {
@@ -480,6 +510,15 @@ func resourceScalewayLbBackendUpdate(ctx context.Context, d *schema.ResourceData
 		FailoverHost:             expandStringPtr(d.Get("failover_host")),
 		SslBridging:              expandBoolPtr(getBool(d, "ssl_bridging")),
 		IgnoreSslServerVerify:    expandBoolPtr(getBool(d, "ignore_ssl_server_verify")),
+		MaxConnections:           expandInt32Ptr(d.Get("max_connections")),
+	}
+
+	if timeoutQueue, ok := d.GetOk("timeout_queue"); ok {
+		timeoutQueueParsed, err := time.ParseDuration(timeoutQueue.(string))
+		if err != nil {
+			return diag.FromErr(err)
+		}
+		req.TimeoutQueue = &scw.Duration{Seconds: int64(timeoutQueueParsed.Seconds())}
 	}
 
 	// deprecated

scaleway/resource_lb_backend_test.go

@@ -86,6 +86,8 @@ func TestAccScalewayLbBackend_Basic(t *testing.T) {
 						on_marked_down_action = "shutdown_sessions"
 						ssl_bridging = "true"
 						ignore_ssl_server_verify = "true"
+						max_connections = 42
+						timeout_queue = "4s"
 					}
 				`,
 				Check: resource.ComposeTestCheckFunc(
@@ -99,6 +101,8 @@ func TestAccScalewayLbBackend_Basic(t *testing.T) {
 					resource.TestCheckResourceAttr("scaleway_lb_backend.bkd01", "on_marked_down_action", "shutdown_sessions"),
 					resource.TestCheckResourceAttr("scaleway_lb_backend.bkd01", "ssl_bridging", "true"),
 					resource.TestCheckResourceAttr("scaleway_lb_backend.bkd01", "ignore_ssl_server_verify", "true"),
+					resource.TestCheckResourceAttr("scaleway_lb_backend.bkd01", "max_connections", "42"),
+					resource.TestCheckResourceAttr("scaleway_lb_backend.bkd01", "timeout_queue", "4s"),
 				),
 			},
 		},