add availability_zones field to ClusterConfiguration

I was also going to use it, but then I noticed that test.Setup does
not validate the test configurations, and then the commit got rather
large as it is.

docs/operators/config.md

@@ -54,6 +54,10 @@ Limes logs all quota changes at the domain and project level in an Open Standard
 A configuration file in YAML format must be provided that describes things like the set of available backend services and the quota/capacity scraping behavior. A minimal config file could look like this:
 
 ```yaml
+availability_zones:
+  - east-1
+  - west-1
+  - west-2
 services:
   - type: compute
   - type: network
@@ -75,6 +79,7 @@ The following fields and sections are supported:
 
 | Field | Required | Description |
 | --- | --- | --- |
+| `availability_zones` | yes | List of availability zones in this cluster. |
 | `catalog_url` | no | URL of Limes API service as it appears in the Keystone service catalog for this cluster. This is only used for version advertisements, and can be omitted if no client relies on the URLs in these version advertisements. |
 | `discovery.method` | no | Defines which method to use to discover Keystone domains and projects in this cluster. If not given, the default value is `list`. |
 | `discovery.except_domains` | no | May contain a regex. Domains whose names match the regex will not be considered by Limes. |

internal/api/api_test.go

@@ -49,6 +49,7 @@ import (
 // as possible
 const (
 	testConfigYAML = `
+		availability_zones: [ az-one, az-two ]
 		discovery:
 			method: --test-static
 		services:

internal/api/inconsistencies_test.go

@@ -29,6 +29,7 @@ import (
 
 const (
 	inconsistenciesTestConfigYAML = `
+		availability_zones: [ az-one, az-two ]
 		discovery:
 			method: --test-static
 		services:

internal/api/removed_test.go

@@ -31,6 +31,7 @@ import (
 func TestForbidClusterIDHeader(t *testing.T) {
 	s := test.NewSetup(t,
 		test.WithConfig(`
+			availability_zones: [ az-one, az-two ]
 			discovery:
 				method: --test-static
 			services:

internal/collector/capacity_scrape_test.go

@@ -36,6 +36,7 @@ import (
 
 const (
 	testScanCapacityConfigYAML = `
+		availability_zones: [ az-one, az-two ]
 		discovery:
 			method: --test-static
 		services:

internal/collector/keystone_test.go

@@ -34,6 +34,7 @@ import (
 
 const (
 	testKeystoneConfigYAML = `
+		availability_zones: [ az-one, az-two ]
 		discovery:
 			method: --test-static
 		services:

internal/collector/ratescrape_test.go

@@ -39,6 +39,7 @@ import (
 
 const (
 	testRateScrapeBasicConfigYAML = `
+		availability_zones: [ az-one, az-two ]
 		discovery:
 			method: --test-static
 			params:

internal/collector/scrape_test.go

@@ -87,6 +87,7 @@ func prepareDomainsAndProjectsForScrape(t *testing.T, s test.Setup) {
 
 const (
 	testScrapeBasicConfigYAML = `
+		availability_zones: [ az-one, az-two ]
 		discovery:
 			method: --test-static
 			params:
@@ -436,6 +437,7 @@ func Test_ScrapeFailure(t *testing.T) {
 
 const (
 	testScrapeCentralizedConfigYAML = `
+		availability_zones: [ az-one, az-two ]
 		discovery:
 			method: --test-static
 			params:
@@ -547,6 +549,7 @@ func Test_ScrapeCentralized(t *testing.T) {
 
 const (
 	testAutoApprovalConfigYAML = `
+		availability_zones: [ az-one, az-two ]
 		discovery:
 			method: --test-static
 			params:
@@ -611,6 +614,7 @@ func Test_AutoApproveInitialQuota(t *testing.T) {
 
 const (
 	testNoopConfigYAML = `
+		availability_zones: [ az-one, az-two ]
 		discovery:
 			method: --test-static
 			params:

internal/core/config.go

@@ -21,7 +21,6 @@ package core
 
 import (
 	"fmt"
-	"os"
 
 	"github.com/sapcc/go-api-declarations/limes"
 	limesrates "github.com/sapcc/go-api-declarations/limes/rates"
@@ -37,10 +36,11 @@ import (
 // cluster. It is instantiated from YAML and then transformed into type
 // Cluster during the startup phase.
 type ClusterConfiguration struct {
-	CatalogURL string                   `yaml:"catalog_url"`
-	Discovery  DiscoveryConfiguration   `yaml:"discovery"`
-	Services   []ServiceConfiguration   `yaml:"services"`
-	Capacitors []CapacitorConfiguration `yaml:"capacitors"`
+	AvailabilityZones []string                 `yaml:"availability_zones"`
+	CatalogURL        string                   `yaml:"catalog_url"`
+	Discovery         DiscoveryConfiguration   `yaml:"discovery"`
+	Services          []ServiceConfiguration   `yaml:"services"`
+	Capacitors        []CapacitorConfiguration `yaml:"capacitors"`
 	//^ Sorry for the stupid pun. Not.
 	Subresources             map[string][]string               `yaml:"subresources"`
 	Subcapacities            map[string][]string               `yaml:"subcapacities"`
@@ -158,20 +158,13 @@ func (c QuotaDistributionConfiguration) InitialProjectQuota() uint64 {
 	}
 }
 
-// NewConfiguration reads and validates the given configuration file.
-// Errors are logged and will result in
-// program termination, causing the function to not return.
-func NewConfiguration(path string) (cluster *Cluster, errs errext.ErrorSet) {
-	//read config file
-	configBytes, err := os.ReadFile(path)
-	if err != nil {
-		errs.Addf("read configuration file: %s", err.Error())
-		return nil, errs
-	}
+// NewClusterFromYAML reads and validates the configuration in the given YAML document.
+// Errors are logged and will result in program termination, causing the function to not return.
+func NewClusterFromYAML(configBytes []byte) (cluster *Cluster, errs errext.ErrorSet) {
 	var config ClusterConfiguration
-	err = yaml.UnmarshalStrict(configBytes, &config)
+	err := yaml.UnmarshalStrict(configBytes, &config)
 	if err != nil {
-		errs.Addf("parse configuration: %s", err.Error())
+		errs.Addf("parse configuration: %w", err)
 		return nil, errs
 	}
 
@@ -196,6 +189,9 @@ func (cluster ClusterConfiguration) validateConfig() (errs errext.ErrorSet) {
 		errs.Addf("missing configuration value: %s", key)
 	}
 
+	if len(cluster.AvailabilityZones) == 0 {
+		missing("availability_zones[]")
+	}
 	if len(cluster.Services) == 0 {
 		missing("services[]")
 	}

internal/test/setup.go

@@ -158,13 +158,7 @@ func initDatabase(t *testing.T, fixtureFile string) *gorp.DbMap {
 }
 
 func initCluster(t *testing.T, configYAML string) *core.Cluster {
-	var cfg core.ClusterConfiguration
-	err := yaml.UnmarshalStrict([]byte(configYAML), &cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	cluster, errs := core.NewCluster(cfg)
+	cluster, errs := core.NewClusterFromYAML([]byte(configYAML))
 	if errs.IsEmpty() {
 		errs = cluster.Connect(nil, gophercloud.EndpointOpts{})
 	}

main.go

@@ -92,7 +92,7 @@ func main() {
 	}
 
 	//load configuration and connect to cluster
-	cluster, errs := core.NewConfiguration(configPath)
+	cluster, errs := core.NewClusterFromYAML(must.Return(os.ReadFile(configPath)))
 	errs.LogFatalIfError()
 	errs = cluster.Connect(provider, eo)
 	errs.LogFatalIfError()