mirror of https://github.com/hashicorp/consul
Frank Schroeder
8 years ago
committed by
Frank Schröder
2 changed files with 159 additions and 151 deletions
@ -0,0 +1,159 @@
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package agent |
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import ( |
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"context" |
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"fmt" |
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"io/ioutil" |
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"log" |
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"net/http" |
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"strings" |
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"golang.org/x/oauth2" |
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"golang.org/x/oauth2/google" |
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compute "google.golang.org/api/compute/v1" |
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) |
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// discoverGCEHosts searches a Google Compute Engine region, returning a list
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// of instance ips that match the tags given in GCETags.
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func (c *Config) discoverGCEHosts(logger *log.Logger) ([]string, error) { |
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config := c.RetryJoinGCE |
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ctx := oauth2.NoContext |
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var client *http.Client |
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var err error |
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logger.Printf("[INFO] agent: Initializing GCE client") |
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if config.CredentialsFile != "" { |
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logger.Printf("[INFO] agent: Loading credentials from %s", config.CredentialsFile) |
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key, err := ioutil.ReadFile(config.CredentialsFile) |
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if err != nil { |
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return nil, err |
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} |
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jwtConfig, err := google.JWTConfigFromJSON(key, compute.ComputeScope) |
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if err != nil { |
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return nil, err |
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} |
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client = jwtConfig.Client(ctx) |
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} else { |
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logger.Printf("[INFO] agent: Using default credential chain") |
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client, err = google.DefaultClient(ctx, compute.ComputeScope) |
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if err != nil { |
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return nil, err |
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} |
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} |
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computeService, err := compute.New(client) |
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if err != nil { |
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return nil, err |
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} |
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if config.ProjectName == "" { |
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logger.Printf("[INFO] agent: No GCE project provided, will discover from metadata.") |
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config.ProjectName, err = gceProjectIDFromMetadata(logger) |
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if err != nil { |
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return nil, err |
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} |
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} else { |
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logger.Printf("[INFO] agent: Using pre-defined GCE project name: %s", config.ProjectName) |
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} |
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zones, err := gceDiscoverZones(ctx, logger, computeService, config.ProjectName, config.ZonePattern) |
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if err != nil { |
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return nil, err |
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} |
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logger.Printf("[INFO] agent: Discovering GCE hosts with tag %s in zones: %s", config.TagValue, strings.Join(zones, ", ")) |
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var servers []string |
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for _, zone := range zones { |
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addresses, err := gceInstancesAddressesForZone(ctx, logger, computeService, config.ProjectName, zone, config.TagValue) |
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if err != nil { |
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return nil, err |
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} |
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if len(addresses) > 0 { |
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logger.Printf("[INFO] agent: Discovered %d instances in %s/%s: %v", len(addresses), config.ProjectName, zone, addresses) |
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} |
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servers = append(servers, addresses...) |
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} |
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return servers, nil |
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} |
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// gceProjectIDFromMetadata queries the metadata service on GCE to get the
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// project ID (name) of an instance.
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func gceProjectIDFromMetadata(logger *log.Logger) (string, error) { |
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logger.Printf("[INFO] agent: Attempting to discover GCE project from metadata.") |
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client := &http.Client{} |
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req, err := http.NewRequest("GET", "http://metadata.google.internal/computeMetadata/v1/project/project-id", nil) |
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if err != nil { |
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return "", err |
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} |
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req.Header.Add("Metadata-Flavor", "Google") |
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resp, err := client.Do(req) |
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if err != nil { |
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return "", err |
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} |
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defer resp.Body.Close() |
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project, err := ioutil.ReadAll(resp.Body) |
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if err != nil { |
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return "", err |
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} |
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logger.Printf("[INFO] agent: GCE project discovered as: %s", project) |
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return string(project), nil |
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} |
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// gceDiscoverZones discovers a list of zones from a supplied zone pattern, or
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// all of the zones available to a project.
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func gceDiscoverZones(ctx context.Context, logger *log.Logger, computeService *compute.Service, project, pattern string) ([]string, error) { |
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var zones []string |
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if pattern != "" { |
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logger.Printf("[INFO] agent: Discovering zones for project %s matching pattern: %s", project, pattern) |
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} else { |
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logger.Printf("[INFO] agent: Discovering all zones available to project: %s", project) |
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} |
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call := computeService.Zones.List(project) |
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if pattern != "" { |
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call = call.Filter(fmt.Sprintf("name eq %s", pattern)) |
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} |
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if err := call.Pages(ctx, func(page *compute.ZoneList) error { |
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for _, v := range page.Items { |
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zones = append(zones, v.Name) |
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} |
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return nil |
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}); err != nil { |
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return zones, err |
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} |
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logger.Printf("[INFO] agent: Discovered GCE zones: %s", strings.Join(zones, ", ")) |
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return zones, nil |
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} |
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// gceInstancesAddressesForZone locates all instances within a specific project
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// and zone, matching the supplied tag. Only the private IP addresses are
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// returned, but ID is also logged.
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func gceInstancesAddressesForZone(ctx context.Context, logger *log.Logger, computeService *compute.Service, project, zone, tag string) ([]string, error) { |
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var addresses []string |
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call := computeService.Instances.List(project, zone) |
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if err := call.Pages(ctx, func(page *compute.InstanceList) error { |
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for _, v := range page.Items { |
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for _, t := range v.Tags.Items { |
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if t == tag && len(v.NetworkInterfaces) > 0 && v.NetworkInterfaces[0].NetworkIP != "" { |
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addresses = append(addresses, v.NetworkInterfaces[0].NetworkIP) |
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} |
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} |
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} |
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return nil |
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}); err != nil { |
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return addresses, err |
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} |
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return addresses, nil |
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} |
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