lib/promscrape/discovery/openstack: code prettifying after cbe3cf683b

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/728

lib/promscrape/discovery/openstack/api.go

@@ -16,27 +16,22 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
 )
 
-const authHeaderName = "X-Auth-Token" // for making requests to openstack api
-
 var configMap = discoveryutils.NewConfigMap()
 
 // apiCredentials can be refreshed
 type apiCredentials struct {
-	// computeURL obtained from auth response and maybe changed
 	computeURL *url.URL
-	// value of authHeaderName
 	token      string
 	expiration time.Time
 }
 
 type apiConfig struct {
-	// client may use tls
 	client *http.Client
 	port   int
-	// tokenLock - guards creds refresh
+	// tokenLock guards creds refresh
 	tokenLock sync.Mutex
 	creds     *apiCredentials
-	// authTokenReq - request for apiCredentials
+	// authTokenReq contins request body for apiCredentials
 	authTokenReq []byte
 	// keystone endpoint
 	endpoint   *url.URL
@@ -50,19 +45,17 @@ func (cfg *apiConfig) getFreshAPICredentials() (*apiCredentials, error) {
 	cfg.tokenLock.Lock()
 	defer cfg.tokenLock.Unlock()
 
-	if time.Until(cfg.creds.expiration) > 10*time.Second {
-
+	if cfg.creds != nil && time.Until(cfg.creds.expiration) > 10*time.Second {
 		// Credentials aren't expired yet.
 		return cfg.creds, nil
 	}
 	newCreds, err := getCreds(cfg)
 	if err != nil {
-		return nil, fmt.Errorf("failed token refresh: %w", err)
+		return nil, fmt.Errorf("cannot refresh OpenStack api token: %w", err)
 	}
-	logger.Infof("refreshed, next : %v", cfg.creds.expiration.String())
 	cfg.creds = newCreds
-
-	return cfg.creds, nil
+	logger.Infof("successfully refreshed OpenStack api token; next expiration: %s", newCreds.expiration)
+	return newCreds, nil
 }
 
 func getAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
@@ -75,22 +68,20 @@ func getAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 
 func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	cfg := &apiConfig{
-		client:       discoveryutils.GetHTTPClient(),
+		client:       &http.Client{},
 		availability: sdc.Availability,
 		region:       sdc.Region,
 		allTenants:   sdc.AllTenants,
 		port:         sdc.Port,
 	}
-
 	if sdc.TLSConfig != nil {
 		config, err := promauth.NewConfig(baseDir, nil, "", "", sdc.TLSConfig)
 		if err != nil {
 			return nil, err
 		}
-		tr := &http.Transport{
+		cfg.client.Transport = &http.Transport{
 			TLSClientConfig: config.NewTLSConfig(),
 		}
-		cfg.client.Transport = tr
 	}
 	// use public compute endpoint by default
 	if len(cfg.availability) == 0 {
@@ -100,7 +91,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	// create new variable to prevent side effects
 	sdcAuth := *sdc
 	// special case if identity_endpoint is not defined
-	if len(sdc.IdentityEndpoint) == 0 {
+	if len(sdcAuth.IdentityEndpoint) == 0 {
 		// override sdc
 		sdcAuth = readCredentialsFromEnv()
 	}
@@ -115,19 +106,15 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 		return nil, err
 	}
 	cfg.authTokenReq = tokenReq
-	token, err := getCreds(cfg)
-	if err != nil {
-		return nil, err
-	}
-	cfg.creds = token
+	// cfg.creds is populated at getFreshAPICredentials
 
 	return cfg, nil
 }
 
-// getCreds - make call to openstack keystone api and retrieves token and computeURL
-// https://docs.openstack.org/api-ref/identity/v3/
+// getCreds makes a call to openstack keystone api and retrieves token and computeURL
+//
+// See https://docs.openstack.org/api-ref/identity/v3/
 func getCreds(cfg *apiConfig) (*apiCredentials, error) {
-
 	apiURL := *cfg.endpoint
 	apiURL.Path = path.Join(apiURL.Path, "auth", "tokens")
 
@@ -143,23 +130,19 @@ func getCreds(cfg *apiConfig) (*apiCredentials, error) {
 	if resp.StatusCode != http.StatusCreated {
 		return nil, fmt.Errorf("auth failed, bad status code: %d, want: 201", resp.StatusCode)
 	}
-
 	at := resp.Header.Get("X-Subject-Token")
 	if len(at) == 0 {
 		return nil, fmt.Errorf("auth failed, response without X-Subject-Token")
 	}
-
 	var ar authResponse
 	if err := json.Unmarshal(r, &ar); err != nil {
 		return nil, fmt.Errorf("cannot parse auth credentials response: %w", err)
 	}
-
 	computeURL, err := getComputeEndpointURL(ar.Token.Catalog, cfg.availability, cfg.region)
 	if err != nil {
-		return nil, fmt.Errorf("cannot get computeEndpoint, account doesn't have enough permissions,"+
-			" availability: %s, region: %s", cfg.availability, cfg.region)
+		return nil, fmt.Errorf("cannot get computeEndpoint, account doesn't have enough permissions, "+
+			"availability: %s, region: %s; error: %w", cfg.availability, cfg.region, err)
 	}
-
 	return &apiCredentials{
 		token:      at,
 		expiration: ar.Token.ExpiresAt,
@@ -167,7 +150,7 @@ func getCreds(cfg *apiConfig) (*apiCredentials, error) {
 	}, nil
 }
 
-// readResponseBody - reads body from http.Response.
+// readResponseBody reads body from http.Response.
 func readResponseBody(resp *http.Response, apiURL string) ([]byte, error) {
 	data, err := ioutil.ReadAll(resp.Body)
 	_ = resp.Body.Close()
@@ -178,26 +161,24 @@ func readResponseBody(resp *http.Response, apiURL string) ([]byte, error) {
 		return nil, fmt.Errorf("unexpected status code for %q; got %d; want %d; response body: %q",
 			apiURL, resp.StatusCode, http.StatusOK, data)
 	}
-
 	return data, nil
 }
 
-// getAPIResponse - makes api call to openstack and returns response body
-func getAPIResponse(href string, cfg *apiConfig) ([]byte, error) {
-	token, err := cfg.getFreshAPICredentials()
+// getAPIResponse calls openstack apiURL and returns response body.
+func getAPIResponse(apiURL string, cfg *apiConfig) ([]byte, error) {
+	creds, err := cfg.getFreshAPICredentials()
 	if err != nil {
-		return nil, fmt.Errorf("failed refresh api credentials: %w", err)
+		return nil, err
 	}
-	req, err := http.NewRequest("GET", href, nil)
+	req, err := http.NewRequest("GET", apiURL, nil)
 	if err != nil {
-		return nil, fmt.Errorf("cannot create new request for openstack api href: %s, err: %w", href, err)
+		return nil, fmt.Errorf("cannot create new request for openstack api url %s: %w", apiURL, err)
 	}
-	req.Header.Set(authHeaderName, token.token)
+	req.Header.Set("X-Auth-Token", creds.token)
 	resp, err := cfg.client.Do(req)
 	if err != nil {
-		return nil, fmt.Errorf("failed query openstack api, href: %s, err : %w", href, err)
+		return nil, fmt.Errorf("cannot query openstack api url %s: %w", apiURL, err)
 	}
-
-	return readResponseBody(resp, href)
+	return readResponseBody(resp, apiURL)
 
 }

lib/promscrape/discovery/openstack/auth.go

@@ -8,8 +8,9 @@ import (
 	"time"
 )
 
-// authResponse - identity api response
-// https://docs.openstack.org/api-ref/identity/v3/?expanded=create-credential-detail,password-authentication-with-unscoped-authorization-detail#authentication-and-token-management
+// authResponse represents identity api response
+//
+// See https://docs.openstack.org/api-ref/identity/v3/#authentication-and-token-management
 type authResponse struct {
 	Token struct {
 		ExpiresAt time.Time     `json:"expires_at,omitempty"`
@@ -24,7 +25,8 @@ type catalogItem struct {
 }
 
 // openstack api endpoint
-// https://docs.openstack.org/api-ref/identity/v3/?expanded=create-credential-detail,password-authentication-with-unscoped-authorization-detail,token-authentication-with-scoped-authorization-detail#list-endpoints
+//
+// See https://docs.openstack.org/api-ref/identity/v3/#list-endpoints
 type endpoint struct {
 	RegionID   string `json:"region_id"`
 	RegionName string `json:"region_name"`
@@ -34,33 +36,30 @@ type endpoint struct {
 	Interface  string `json:"interface"`
 }
 
-// getComputeEndpointURL extracts compute url endpoint with given filters from keystone catalog
+// getComputeEndpointURL extracts compute endpoint url with given filters from keystone catalog
 func getComputeEndpointURL(catalog []catalogItem, availability, region string) (*url.URL, error) {
 	for _, eps := range catalog {
-		if eps.Type == "compute" {
-			for _, ep := range eps.Endpoints {
-				if ep.Interface == availability && (len(region) == 0 || region == ep.RegionID || region == ep.RegionName) {
-					return url.Parse(ep.URL)
-				}
+		if eps.Type != "compute" {
+			continue
+		}
+		for _, ep := range eps.Endpoints {
+			if ep.Interface == availability && (len(region) == 0 || region == ep.RegionID || region == ep.RegionName) {
+				return url.Parse(ep.URL)
 			}
 		}
 	}
-	return nil, fmt.Errorf("cannot excract compute url from catalog, availability: %s, region: %s ", availability, region)
+	return nil, fmt.Errorf("cannot find compute url for the given availability: %q, region: %q", availability, region)
 }
 
-// buildAuthRequestBody - builds request for authentication.
+// buildAuthRequestBody builds request for authentication
 func buildAuthRequestBody(sdc *SDConfig) ([]byte, error) {
-
-	// fast path
 	if len(sdc.Password) == 0 && len(sdc.ApplicationCredentialID) == 0 && len(sdc.ApplicationCredentialName) == 0 {
-		return nil, fmt.Errorf("password and application credentials is missing")
+		return nil, fmt.Errorf("password and application credentials are missing")
 	}
-
 	type domainReq struct {
 		ID   *string `json:"id,omitempty"`
 		Name *string `json:"name,omitempty"`
 	}
-
 	type userReq struct {
 		ID       *string    `json:"id,omitempty"`
 		Name     *string    `json:"name,omitempty"`
@@ -68,34 +67,28 @@ func buildAuthRequestBody(sdc *SDConfig) ([]byte, error) {
 		Passcode *string    `json:"passcode,omitempty"`
 		Domain   *domainReq `json:"domain,omitempty"`
 	}
-
 	type passwordReq struct {
 		User userReq `json:"user"`
 	}
-
 	type tokenReq struct {
 		ID string `json:"id"`
 	}
-
 	type applicationCredentialReq struct {
 		ID     *string  `json:"id,omitempty"`
 		Name   *string  `json:"name,omitempty"`
 		User   *userReq `json:"user,omitempty"`
 		Secret *string  `json:"secret,omitempty"`
 	}
-
 	type identityReq struct {
 		Methods               []string                  `json:"methods"`
 		Password              *passwordReq              `json:"password,omitempty"`
 		Token                 *tokenReq                 `json:"token,omitempty"`
 		ApplicationCredential *applicationCredentialReq `json:"application_credential,omitempty"`
 	}
-
 	type authReq struct {
 		Identity identityReq            `json:"identity"`
 		Scope    map[string]interface{} `json:"scope,omitempty"`
 	}
-
 	type request struct {
 		Auth authReq `json:"auth"`
 	}
@@ -118,84 +111,62 @@ func buildAuthRequestBody(sdc *SDConfig) ([]byte, error) {
 				ID:     &sdc.ApplicationCredentialID,
 				Secret: &sdc.ApplicationCredentialSecret,
 			}
-
-			// fast path unscoped
 			return json.Marshal(req)
 		}
 
-		// application_credential_name auth
 		if len(sdc.ApplicationCredentialSecret) == 0 {
-			return nil, fmt.Errorf("application_credential_name is not empty and application_credential_secret is empty")
+			return nil, fmt.Errorf("missing application_credential_secret when application_credential_name is set")
 		}
-
 		var userRequest *userReq
-
 		if len(sdc.UserID) > 0 {
 			// UserID could be used without the domain information
 			userRequest = &userReq{
 				ID: &sdc.UserID,
 			}
 		}
-
 		if userRequest == nil && len(sdc.Username) == 0 {
-			// Make sure that Username or UserID are provided
 			return nil, fmt.Errorf("username and userid is empty")
 		}
-
 		if userRequest == nil && len(sdc.DomainID) > 0 {
 			userRequest = &userReq{
 				Name:   &sdc.Username,
 				Domain: &domainReq{ID: &sdc.DomainID},
 			}
 		}
-
 		if userRequest == nil && len(sdc.DomainName) > 0 {
 			userRequest = &userReq{
 				Name:   &sdc.Username,
 				Domain: &domainReq{Name: &sdc.DomainName},
 			}
 		}
-
-		// Make sure that domain_id or domain_name are provided among username
 		if userRequest == nil {
-			return nil, fmt.Errorf("domain_id and domain_name is empty for application_credential_name auth")
+			return nil, fmt.Errorf("domain_id and domain_name cannot be empty for application_credential_name auth")
 		}
-
 		req.Auth.Identity.Methods = []string{"application_credential"}
 		req.Auth.Identity.ApplicationCredential = &applicationCredentialReq{
 			Name:   &sdc.ApplicationCredentialName,
 			User:   userRequest,
 			Secret: &sdc.ApplicationCredentialSecret,
 		}
-
-		// fast path unscoped
 		return json.Marshal(req)
 	}
 
 	// Password authentication.
 	req.Auth.Identity.Methods = append(req.Auth.Identity.Methods, "password")
-
-	// At least one of Username and UserID must be specified.
 	if len(sdc.Username) == 0 && len(sdc.UserID) == 0 {
 		return nil, fmt.Errorf("username and userid is empty for username/password auth")
 	}
-
 	if len(sdc.Username) > 0 {
-		// If Username is provided, UserID may not be provided.
 		if len(sdc.UserID) > 0 {
 			return nil, fmt.Errorf("both username and userid is present")
 		}
-
-		// Either DomainID or DomainName must also be specified.
 		if len(sdc.DomainID) == 0 && len(sdc.DomainName) == 0 {
 			return nil, fmt.Errorf(" domain_id or domain_name is missing for username/password auth: %s", sdc.Username)
 		}
-
 		if len(sdc.DomainID) > 0 {
 			if sdc.DomainName != "" {
 				return nil, fmt.Errorf("both domain_id and domain_name is present")
 			}
-
 			// Configure the request for Username and Password authentication with a DomainID.
 			if len(sdc.Password) > 0 {
 				req.Auth.Identity.Password = &passwordReq{
@@ -207,7 +178,6 @@ func buildAuthRequestBody(sdc *SDConfig) ([]byte, error) {
 				}
 			}
 		}
-
 		if len(sdc.DomainName) > 0 {
 			// Configure the request for Username and Password authentication with a DomainName.
 			if len(sdc.Password) > 0 {
@@ -221,16 +191,13 @@ func buildAuthRequestBody(sdc *SDConfig) ([]byte, error) {
 			}
 		}
 	}
-
 	if len(sdc.UserID) > 0 {
-		// If UserID is specified, neither DomainID nor DomainName may be.
 		if len(sdc.DomainID) > 0 {
 			return nil, fmt.Errorf("both user_id and domain_id is present")
 		}
 		if len(sdc.DomainName) > 0 {
 			return nil, fmt.Errorf("both user_id and domain_name is present")
 		}
-
 		// Configure the request for UserID and Password authentication.
 		if len(sdc.Password) > 0 {
 			req.Auth.Identity.Password = &passwordReq{
@@ -251,19 +218,16 @@ func buildAuthRequestBody(sdc *SDConfig) ([]byte, error) {
 	if len(scope) > 0 {
 		req.Auth.Scope = scope
 	}
-
 	return json.Marshal(req)
 }
 
-// buildScope - adds scope information into auth request
-// https://docs.openstack.org/api-ref/identity/v3/?expanded=password-authentication-with-scoped-authorization-detail#password-authentication-with-unscoped-authorization
+// buildScope adds scope information into auth request
+//
+// See https://docs.openstack.org/api-ref/identity/v3/#password-authentication-with-unscoped-authorization
 func buildScope(sdc *SDConfig) (map[string]interface{}, error) {
-
-	// fast path
 	if len(sdc.ProjectName) == 0 && len(sdc.ProjectID) == 0 && len(sdc.DomainID) == 0 && len(sdc.DomainName) == 0 {
 		return nil, nil
 	}
-
 	if len(sdc.ProjectName) > 0 {
 		// ProjectName provided: either DomainID or DomainName must also be supplied.
 		// ProjectID may not be supplied.
@@ -273,10 +237,7 @@ func buildScope(sdc *SDConfig) (map[string]interface{}, error) {
 		if len(sdc.ProjectID) > 0 {
 			return nil, fmt.Errorf("both domain_id and domain_name present")
 		}
-
 		if len(sdc.DomainID) > 0 {
-
-			// ProjectName + DomainID
 			return map[string]interface{}{
 				"project": map[string]interface{}{
 					"name":   &sdc.ProjectName,
@@ -284,10 +245,7 @@ func buildScope(sdc *SDConfig) (map[string]interface{}, error) {
 				},
 			}, nil
 		}
-
 		if len(sdc.DomainName) > 0 {
-
-			// ProjectName + DomainName
 			return map[string]interface{}{
 				"project": map[string]interface{}{
 					"name":   &sdc.ProjectName,
@@ -303,39 +261,31 @@ func buildScope(sdc *SDConfig) (map[string]interface{}, error) {
 		if len(sdc.DomainName) > 0 {
 			return nil, fmt.Errorf("both project_id and domain_name present")
 		}
-
-		// ProjectID
 		return map[string]interface{}{
 			"project": map[string]interface{}{
 				"id": &sdc.ProjectID,
 			},
 		}, nil
 	} else if len(sdc.DomainID) > 0 {
-		// DomainID provided. ProjectID, ProjectName, and DomainName may not be provided.
 		if len(sdc.DomainName) > 0 {
 			return nil, fmt.Errorf("both domain_id and domain_name present")
 		}
-
-		// DomainID
 		return map[string]interface{}{
 			"domain": map[string]interface{}{
 				"id": &sdc.DomainID,
 			},
 		}, nil
 	} else if len(sdc.DomainName) > 0 {
-
-		// DomainName
 		return map[string]interface{}{
 			"domain": map[string]interface{}{
 				"name": &sdc.DomainName,
 			},
 		}, nil
 	}
-
 	return nil, nil
 }
 
-// readCredentialsFromEnv - obtains serviceDiscoveryConfig from env variables for openstack
+// readCredentialsFromEnv obtains serviceDiscoveryConfig from env variables for openstack
 func readCredentialsFromEnv() SDConfig {
 	authURL := os.Getenv("OS_AUTH_URL")
 	username := os.Getenv("OS_USERNAME")
@@ -352,7 +302,6 @@ func readCredentialsFromEnv() SDConfig {
 	if v := os.Getenv("OS_PROJECT_ID"); v != "" {
 		tenantID = v
 	}
-
 	// If OS_PROJECT_NAME is set, overwrite tenantName with the value.
 	if v := os.Getenv("OS_PROJECT_NAME"); v != "" {
 		tenantName = v

lib/promscrape/discovery/openstack/hypervisor.go

@@ -9,7 +9,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
 )
 
-// https://docs.openstack.org/api-ref/compute/?expanded=list-servers-detailed-detail#list-hypervisors-details
+// See https://docs.openstack.org/api-ref/compute/#list-hypervisors-details
 type hypervisorDetail struct {
 	Hypervisors []hypervisor `json:"hypervisors"`
 	Links       []struct {
@@ -32,12 +32,15 @@ func parseHypervisorDetail(data []byte) (*hypervisorDetail, error) {
 	if err := json.Unmarshal(data, &hvsd); err != nil {
 		return nil, fmt.Errorf("cannot parse hypervisorDetail: %w", err)
 	}
-
 	return &hvsd, nil
 }
 
 func (cfg *apiConfig) getHypervisors() ([]hypervisor, error) {
-	computeURL := *cfg.creds.computeURL
+	creds, err := cfg.getFreshAPICredentials()
+	if err != nil {
+		return nil, err
+	}
+	computeURL := *creds.computeURL
 	computeURL.Path = path.Join(computeURL.Path, "os-hypervisors", "detail")
 	nextLink := computeURL.String()
 	var hvs []hypervisor
@@ -46,19 +49,15 @@ func (cfg *apiConfig) getHypervisors() ([]hypervisor, error) {
 		if err != nil {
 			return nil, err
 		}
-
 		detail, err := parseHypervisorDetail(resp)
 		if err != nil {
 			return nil, err
 		}
 		hvs = append(hvs, detail.Hypervisors...)
-
-		if len(detail.Links) > 0 {
-			nextLink = detail.Links[0].HREF
-			continue
+		if len(detail.Links) == 0 {
+			return hvs, nil
 		}
-
-		return hvs, nil
+		nextLink = detail.Links[0].HREF
 	}
 }
 
@@ -77,7 +76,6 @@ func addHypervisorLabels(hvs []hypervisor, port int) []map[string]string {
 		}
 		ms = append(ms, m)
 	}
-
 	return ms
 }
 
@@ -86,6 +84,5 @@ func getHypervisorLabels(cfg *apiConfig) ([]map[string]string, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot get hypervisors: %w", err)
 	}
-
 	return addHypervisorLabels(hvs, cfg.port), nil
 }

lib/promscrape/discovery/openstack/instance.go

@@ -4,11 +4,12 @@ import (
 	"encoding/json"
 	"fmt"
 	"path"
+	"sort"
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
 )
 
-// https://docs.openstack.org/api-ref/compute/?expanded=list-servers-detailed-detail#list-servers
+// See https://docs.openstack.org/api-ref/compute/#list-servers
 type serversDetail struct {
 	Servers []server `json:"servers"`
 	Links   []struct {
@@ -40,7 +41,6 @@ func parseServersDetail(data []byte) (*serversDetail, error) {
 	if err := json.Unmarshal(data, &srvd); err != nil {
 		return nil, fmt.Errorf("cannot parse serversDetail: %w", err)
 	}
-
 	return &srvd, nil
 }
 
@@ -55,13 +55,20 @@ func addInstanceLabels(servers []server, port int) []map[string]string {
 			"__meta_openstack_user_id":         server.UserID,
 			"__meta_openstack_instance_flavor": server.Flavor.ID,
 		}
-
 		for k, v := range server.Metadata {
 			m["__meta_openstack_tag_"+discoveryutils.SanitizeLabelName(k)] = v
 		}
-		for pool, addresses := range server.Addresses {
+		// Traverse server.Addresses in alphabetical order of pool name
+		// in order to return targets in deterministic order.
+		sortedPools := make([]string, 0, len(server.Addresses))
+		for pool := range server.Addresses {
+			sortedPools = append(sortedPools, pool)
+		}
+		sort.Strings(sortedPools)
+		for _, pool := range sortedPools {
+			addresses := server.Addresses[pool]
 			if len(addresses) == 0 {
-				// pool with zero addresses skip it
+				// skip pool with zero addresses
 				continue
 			}
 			var publicIP string
@@ -90,7 +97,6 @@ func addInstanceLabels(servers []server, port int) []map[string]string {
 				}
 				lbls["__address__"] = discoveryutils.JoinHostPort(ip.Address, port)
 				ms = append(ms, lbls)
-
 			}
 		}
 	}
@@ -98,7 +104,11 @@ func addInstanceLabels(servers []server, port int) []map[string]string {
 }
 
 func (cfg *apiConfig) getServers() ([]server, error) {
-	computeURL := *cfg.creds.computeURL
+	creds, err := cfg.getFreshAPICredentials()
+	if err != nil {
+		return nil, err
+	}
+	computeURL := *creds.computeURL
 	computeURL.Path = path.Join(computeURL.Path, "servers", "detail")
 	// by default, query fetches data from all tenants
 	if !cfg.allTenants {
@@ -106,28 +116,22 @@ func (cfg *apiConfig) getServers() ([]server, error) {
 		q.Set("all_tenants", "false")
 		computeURL.RawQuery = q.Encode()
 	}
-
 	nextLink := computeURL.String()
-
 	var servers []server
 	for {
 		resp, err := getAPIResponse(nextLink, cfg)
 		if err != nil {
 			return nil, err
 		}
-
 		serversDetail, err := parseServersDetail(resp)
 		if err != nil {
 			return nil, err
 		}
 		servers = append(servers, serversDetail.Servers...)
-
-		if len(serversDetail.Links) > 0 {
-			nextLink = serversDetail.Links[0].HREF
-			continue
+		if len(serversDetail.Links) == 0 {
+			return servers, nil
 		}
-
-		return servers, nil
+		nextLink = serversDetail.Links[0].HREF
 	}
 }
 
@@ -137,5 +141,4 @@ func getInstancesLabels(cfg *apiConfig) ([]map[string]string, error) {
 		return nil, err
 	}
 	return addInstanceLabels(srv, cfg.port), nil
-
 }

lib/promscrape/discovery/openstack/instance_test.go

@@ -19,13 +19,13 @@ func Test_addInstanceLabels(t *testing.T) {
 		want [][]prompbmarshal.Label
 	}{
 		{
-			name: "empty response",
+			name: "empty_response",
 			args: args{
 				port: 9100,
 			},
 		},
 		{
-			name: "1 server",
+			name: "one_server",
 			args: args{
 				port: 9100,
 				servers: []server{
@@ -70,7 +70,7 @@ func Test_addInstanceLabels(t *testing.T) {
 			},
 		},
 		{
-			name: "with public ip",
+			name: "with_public_ip",
 			args: args{
 				port: 9100,
 				servers: []server{
@@ -113,6 +113,17 @@ func Test_addInstanceLabels(t *testing.T) {
 				},
 			},
 			want: [][]prompbmarshal.Label{
+				discoveryutils.GetSortedLabels(map[string]string{
+					"__address__":                      "10.10.0.1:9100",
+					"__meta_openstack_address_pool":    "internal",
+					"__meta_openstack_instance_flavor": "5",
+					"__meta_openstack_instance_id":     "10",
+					"__meta_openstack_instance_name":   "server-2",
+					"__meta_openstack_instance_status": "enabled",
+					"__meta_openstack_private_ip":      "10.10.0.1",
+					"__meta_openstack_project_id":      "some-tenant-id",
+					"__meta_openstack_user_id":         "some-user-id",
+				}),
 				discoveryutils.GetSortedLabels(map[string]string{
 					"__address__":                      "192.168.0.1:9100",
 					"__meta_openstack_address_pool":    "test",
@@ -125,24 +136,12 @@ func Test_addInstanceLabels(t *testing.T) {
 					"__meta_openstack_project_id":      "some-tenant-id",
 					"__meta_openstack_user_id":         "some-user-id",
 				}),
-				discoveryutils.GetSortedLabels(map[string]string{
-					"__address__":                      "10.10.0.1:9100",
-					"__meta_openstack_address_pool":    "internal",
-					"__meta_openstack_instance_flavor": "5",
-					"__meta_openstack_instance_id":     "10",
-					"__meta_openstack_instance_name":   "server-2",
-					"__meta_openstack_instance_status": "enabled",
-					"__meta_openstack_private_ip":      "10.10.0.1",
-					"__meta_openstack_project_id":      "some-tenant-id",
-					"__meta_openstack_user_id":         "some-user-id",
-				}),
 			},
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			got := addInstanceLabels(tt.args.servers, tt.args.port)
-
 			var sortedLabelss [][]prompbmarshal.Label
 			for _, labels := range got {
 				sortedLabelss = append(sortedLabelss, discoveryutils.GetSortedLabels(labels))

lib/promscrape/discovery/openstack/openstack.go

@@ -7,24 +7,28 @@ import (
 )
 
 // SDConfig is the configuration for OpenStack based service discovery.
+//
+// See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#openstack_sd_config
 type SDConfig struct {
-	IdentityEndpoint            string              `yaml:"identity_endpoint"`
-	Username                    string              `yaml:"username"`
-	UserID                      string              `yaml:"userid"`
-	Password                    string              `yaml:"password"`
-	ProjectName                 string              `yaml:"project_name"`
-	ProjectID                   string              `yaml:"project_id"`
-	DomainName                  string              `yaml:"domain_name"`
-	DomainID                    string              `yaml:"domain_id"`
-	ApplicationCredentialName   string              `yaml:"application_credential_name"`
-	ApplicationCredentialID     string              `yaml:"application_credential_id"`
-	ApplicationCredentialSecret string              `yaml:"application_credential_secret"`
-	Role                        string              `yaml:"role"`
-	Region                      string              `yaml:"region"`
-	Port                        int                 `yaml:"port"`
-	AllTenants                  bool                `yaml:"all_tenants"`
-	TLSConfig                   *promauth.TLSConfig `yaml:"tls_config"`
-	Availability                string              `yaml:"availability"`
+	IdentityEndpoint            string `yaml:"identity_endpoint"`
+	Username                    string `yaml:"username"`
+	UserID                      string `yaml:"userid"`
+	Password                    string `yaml:"password"`
+	ProjectName                 string `yaml:"project_name"`
+	ProjectID                   string `yaml:"project_id"`
+	DomainName                  string `yaml:"domain_name"`
+	DomainID                    string `yaml:"domain_id"`
+	ApplicationCredentialName   string `yaml:"application_credential_name"`
+	ApplicationCredentialID     string `yaml:"application_credential_id"`
+	ApplicationCredentialSecret string `yaml:"application_credential_secret"`
+	Role                        string `yaml:"role"`
+	Region                      string `yaml:"region"`
+	// RefreshInterval time.Duration `yaml:"refresh_interval"`
+	// refresh_interval is obtained from `-promscrape.openstackSDCheckInterval` command-line option.
+	Port         int                 `yaml:"port"`
+	AllTenants   bool                `yaml:"all_tenants"`
+	TLSConfig    *promauth.TLSConfig `yaml:"tls_config"`
+	Availability string              `yaml:"availability"`
 }
 
 // GetLabels returns gce labels according to sdc.