open-nomad/api/services.go
Seth Hoenig 14c7cebdea connect: enable automatic expose paths for individual group service checks
Part of #6120

Building on the support for enabling connect proxy paths in #7323, this change
adds the ability to configure the 'service.check.expose' flag on group-level
service check definitions for services that are connect-enabled. This is a slight
deviation from the "magic" that Consul provides. With Consul, the 'expose' flag
exists on the connect.proxy stanza, which will then auto-generate expose paths
for every HTTP and gRPC service check associated with that connect-enabled
service.

A first attempt at providing similar magic for Nomad's Consul Connect integration
followed that pattern exactly, as seen in #7396. However, on reviewing the PR
we realized having the `expose` flag on the proxy stanza inseperably ties together
the automatic path generation with every HTTP/gRPC defined on the service. This
makes sense in Consul's context, because a service definition is reasonably
associated with a single "task". With Nomad's group level service definitions
however, there is a reasonable expectation that a service definition is more
abstractly representative of multiple services within the task group. In this
case, one would want to define checks of that service which concretely make HTTP
or gRPC requests to different underlying tasks. Such a model is not possible
with the course `proxy.expose` flag.

Instead, we now have the flag made available within the check definitions themselves.
By making the expose feature resolute to each check, it is possible to have
some HTTP/gRPC checks which make use of the envoy exposed paths, as well as
some HTTP/gRPC checks which make use of some orthongonal port-mapping to do
checks on some other task (or even some other bound port of the same task)
within the task group.

Given this example,

group "server-group" {
  network {
    mode = "bridge"
    port "forchecks" {
      to = -1
    }
  }

  service {
    name = "myserver"
    port = 2000

    connect {
      sidecar_service {
      }
    }

    check {
      name     = "mycheck-myserver"
      type     = "http"
      port     = "forchecks"
      interval = "3s"
      timeout  = "2s"
      method   = "GET"
      path     = "/classic/responder/health"
      expose   = true
    }
  }
}

Nomad will automatically inject (via job endpoint mutator) the
extrapolated expose path configuration, i.e.

expose {
  path {
    path            = "/classic/responder/health"
    protocol        = "http"
    local_path_port = 2000
    listener_port   = "forchecks"
  }
}

Documentation is coming in #7440 (needs updating, doing next)

Modifications to the `countdash` examples in https://github.com/hashicorp/demo-consul-101/pull/6
which will make the examples in the documentation actually runnable.

Will add some e2e tests based on the above when it becomes available.
2020-03-31 17:15:50 -06:00

195 lines
5.2 KiB
Go

package api
import (
"fmt"
"time"
)
// CheckRestart describes if and when a task should be restarted based on
// failing health checks.
type CheckRestart struct {
Limit int `mapstructure:"limit"`
Grace *time.Duration `mapstructure:"grace"`
IgnoreWarnings bool `mapstructure:"ignore_warnings"`
}
// Canonicalize CheckRestart fields if not nil.
func (c *CheckRestart) Canonicalize() {
if c == nil {
return
}
if c.Grace == nil {
c.Grace = timeToPtr(1 * time.Second)
}
}
// Copy returns a copy of CheckRestart or nil if unset.
func (c *CheckRestart) Copy() *CheckRestart {
if c == nil {
return nil
}
nc := new(CheckRestart)
nc.Limit = c.Limit
if c.Grace != nil {
g := *c.Grace
nc.Grace = &g
}
nc.IgnoreWarnings = c.IgnoreWarnings
return nc
}
// Merge values from other CheckRestart over default values on this
// CheckRestart and return merged copy.
func (c *CheckRestart) Merge(o *CheckRestart) *CheckRestart {
if c == nil {
// Just return other
return o
}
nc := c.Copy()
if o == nil {
// Nothing to merge
return nc
}
if o.Limit > 0 {
nc.Limit = o.Limit
}
if o.Grace != nil {
nc.Grace = o.Grace
}
if o.IgnoreWarnings {
nc.IgnoreWarnings = o.IgnoreWarnings
}
return nc
}
// ServiceCheck represents the consul health check that Nomad registers.
type ServiceCheck struct {
//FIXME Id is unused. Remove?
Id string
Name string
Type string
Command string
Args []string
Path string
Protocol string
PortLabel string `mapstructure:"port"`
Expose bool
AddressMode string `mapstructure:"address_mode"`
Interval time.Duration
Timeout time.Duration
InitialStatus string `mapstructure:"initial_status"`
TLSSkipVerify bool `mapstructure:"tls_skip_verify"`
Header map[string][]string
Method string
CheckRestart *CheckRestart `mapstructure:"check_restart"`
GRPCService string `mapstructure:"grpc_service"`
GRPCUseTLS bool `mapstructure:"grpc_use_tls"`
TaskName string `mapstructure:"task"`
}
// Service represents a Consul service definition.
type Service struct {
//FIXME Id is unused. Remove?
Id string
Name string
Tags []string
CanaryTags []string `mapstructure:"canary_tags"`
EnableTagOverride bool `mapstructure:"enable_tag_override"`
PortLabel string `mapstructure:"port"`
AddressMode string `mapstructure:"address_mode"`
Checks []ServiceCheck
CheckRestart *CheckRestart `mapstructure:"check_restart"`
Connect *ConsulConnect
Meta map[string]string
CanaryMeta map[string]string
}
// Canonicalize the Service by ensuring its name and address mode are set. Task
// will be nil for group services.
func (s *Service) Canonicalize(t *Task, tg *TaskGroup, job *Job) {
if s.Name == "" {
if t != nil {
s.Name = fmt.Sprintf("%s-%s-%s", *job.Name, *tg.Name, t.Name)
} else {
s.Name = fmt.Sprintf("%s-%s", *job.Name, *tg.Name)
}
}
// Default to AddressModeAuto
if s.AddressMode == "" {
s.AddressMode = "auto"
}
// Canonicalize CheckRestart on Checks and merge Service.CheckRestart
// into each check.
for i, check := range s.Checks {
s.Checks[i].CheckRestart = s.CheckRestart.Merge(check.CheckRestart)
s.Checks[i].CheckRestart.Canonicalize()
}
}
// ConsulConnect represents a Consul Connect jobspec stanza.
type ConsulConnect struct {
Native bool
SidecarService *ConsulSidecarService `mapstructure:"sidecar_service"`
SidecarTask *SidecarTask `mapstructure:"sidecar_task"`
}
// ConsulSidecarService represents a Consul Connect SidecarService jobspec
// stanza.
type ConsulSidecarService struct {
Tags []string
Port string
Proxy *ConsulProxy
}
// SidecarTask represents a subset of Task fields that can be set to override
// the fields of the Task generated for the sidecar
type SidecarTask struct {
Name string
Driver string
User string
Config map[string]interface{}
Env map[string]string
Resources *Resources
Meta map[string]string
KillTimeout *time.Duration `mapstructure:"kill_timeout"`
LogConfig *LogConfig `mapstructure:"logs"`
ShutdownDelay *time.Duration `mapstructure:"shutdown_delay"`
KillSignal string `mapstructure:"kill_signal"`
}
// ConsulProxy represents a Consul Connect sidecar proxy jobspec stanza.
type ConsulProxy struct {
LocalServiceAddress string `mapstructure:"local_service_address"`
LocalServicePort int `mapstructure:"local_service_port"`
ExposeConfig *ConsulExposeConfig `mapstructure:"expose"`
Upstreams []*ConsulUpstream
Config map[string]interface{}
}
// ConsulUpstream represents a Consul Connect upstream jobspec stanza.
type ConsulUpstream struct {
DestinationName string `mapstructure:"destination_name"`
LocalBindPort int `mapstructure:"local_bind_port"`
}
type ConsulExposeConfig struct {
Path []*ConsulExposePath `mapstructure:"path"`
}
type ConsulExposePath struct {
Path string
Protocol string
LocalPathPort int `mapstructure:"local_path_port"`
ListenerPort string `mapstructure:"listener_port"`
}