Implement config reading

- support config file
- support reading checks, server definition and endpoint definitions from env

.gitignore

@@ -15,4 +15,5 @@
 # vendor/
 
 dist/
-.idea/
+.idea/
+cue.mod/

check/api.go

@@ -4,12 +4,26 @@ import (
 	"context"
 	"errors"
 
+	"github.com/baez90/nurse/config"
 	"github.com/baez90/nurse/grammar"
 )
 
-var ErrNoSuchCheck = errors.New("no such check")
+var (
+	ErrNoSuchCheck      = errors.New("no such check")
+	ErrConflictingCheck = errors.New("check with same name already registered")
+)
 
-type SystemChecker interface {
+type (
-	grammar.CheckUnmarshaler
+	Unmarshaler interface {
-	Execute(ctx context.Context) error
+		UnmarshalCheck(c grammar.Check, lookup config.ServerLookup) error
-}
+	}
+
+	SystemChecker interface {
+		Unmarshaler
+		Execute(ctx context.Context) error
+	}
+
+	CallUnmarshaler interface {
+		UnmarshalCall(c grammar.Call) error
+	}
+)

check/modules.go

@@ -0,0 +1,91 @@
+package check
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/baez90/nurse/config"
+	"github.com/baez90/nurse/grammar"
+)
+
+type (
+	ModuleOption interface {
+		Apply(m *Module) error
+	}
+
+	ModuleOptionFunc func(m *Module) error
+
+	Factory interface {
+		New() SystemChecker
+	}
+
+	FactoryFunc func() SystemChecker
+)
+
+func (f ModuleOptionFunc) Apply(m *Module) error {
+	return f(m)
+}
+
+func (f FactoryFunc) New() SystemChecker {
+	return f()
+}
+
+func WithCheck(name string, factory Factory) ModuleOption {
+	return ModuleOptionFunc(func(m *Module) error {
+		return m.Register(name, factory)
+	})
+}
+
+func NewModule(opts ...ModuleOption) (*Module, error) {
+	m := &Module{
+		knownChecks: make(map[string]Factory),
+	}
+
+	for i := range opts {
+		if err := opts[i].Apply(m); err != nil {
+			return nil, err
+		}
+	}
+
+	return m, nil
+}
+
+type Module struct {
+	lock        sync.RWMutex
+	knownChecks map[string]Factory
+}
+
+func (m *Module) Lookup(c grammar.Check, srvLookup config.ServerLookup) (SystemChecker, error) {
+	m.lock.RLock()
+	defer m.lock.RUnlock()
+	var (
+		factory Factory
+		ok      bool
+	)
+	if factory, ok = m.knownChecks[strings.ToLower(c.Initiator.Name)]; !ok {
+		return nil, fmt.Errorf("%w: %s", ErrNoSuchCheck, c.Initiator.Name)
+	}
+
+	chk := factory.New()
+	if err := chk.UnmarshalCheck(c, srvLookup); err != nil {
+		return nil, err
+	}
+
+	return chk, nil
+}
+
+func (m *Module) Register(name string, factory Factory) error {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	name = strings.ToLower(name)
+
+	if _, ok := m.knownChecks[name]; ok {
+		return fmt.Errorf("%w: %s", ErrConflictingCheck, name)
+	}
+
+	m.knownChecks[name] = factory
+
+	return nil
+}

config/app_config.go

@@ -0,0 +1,91 @@
+package config
+
+import (
+	"io"
+	"os"
+	"time"
+)
+
+type (
+	Option interface {
+		Extend(n Nurse) (Nurse, error)
+	}
+	OptionFunc func(n Nurse) (Nurse, error)
+)
+
+func (f OptionFunc) Extend(n Nurse) (Nurse, error) {
+	return f(n)
+}
+
+func New(opts ...Option) (*Nurse, error) {
+	var (
+		inst Nurse
+		err  error
+	)
+
+	for i := range opts {
+		if inst, err = opts[i].Extend(inst); err != nil {
+			return nil, err
+		}
+	}
+
+	return &inst, nil
+}
+
+type Nurse struct {
+	Servers      map[string]Server
+	Endpoints    map[Route]EndpointSpec
+	CheckTimeout time.Duration
+}
+
+// Merge merges the current Nurse instance with another one
+// giving the current instance precedence means no set value is overwritten
+func (n Nurse) Merge(other Nurse) Nurse {
+	if n.CheckTimeout == 0 {
+		n.CheckTimeout = other.CheckTimeout
+	}
+
+	for name, srv := range other.Servers {
+		if _, ok := n.Servers[name]; !ok {
+			n.Servers[name] = srv
+		}
+	}
+
+	return n
+}
+
+func (n *Nurse) Unmarshal(reader io.ReadSeeker) error {
+	providers := []func(io.Reader) configDecoder{
+		newYAMLDecoder,
+		newJSONDecoder,
+	}
+
+	for i := range providers {
+		if err := n.tryUnmarshal(reader, providers[i]); err == nil {
+			return nil
+		}
+	}
+
+	return nil
+}
+
+func (n *Nurse) ReadFromFile(configFilePath string) error {
+	if file, err := os.Open(configFilePath); err != nil {
+		return err
+	} else {
+		defer func() {
+			_ = file.Close()
+		}()
+
+		return n.Unmarshal(file)
+	}
+}
+
+func (n *Nurse) tryUnmarshal(seeker io.ReadSeeker, prov func(reader io.Reader) configDecoder) error {
+	if _, err := seeker.Seek(0, 0); err != nil {
+		return err
+	}
+
+	decoder := prov(seeker)
+	return decoder.DecodeConfig(n)
+}

config/decoder.go

@@ -0,0 +1,41 @@
+package config
+
+import (
+	"encoding/json"
+	"io"
+
+	"gopkg.in/yaml.v3"
+)
+
+var (
+	_ configDecoder = (*jsonDecoder)(nil)
+	_ configDecoder = (*yamlDecoder)(nil)
+)
+
+type configDecoder interface {
+	DecodeConfig(into *Nurse) error
+}
+
+func newJSONDecoder(r io.Reader) configDecoder {
+	return &jsonDecoder{decoder: json.NewDecoder(r)}
+}
+
+type jsonDecoder struct {
+	decoder *json.Decoder
+}
+
+func (j jsonDecoder) DecodeConfig(into *Nurse) error {
+	return j.decoder.Decode(into)
+}
+
+func newYAMLDecoder(r io.Reader) configDecoder {
+	return &yamlDecoder{decoder: yaml.NewDecoder(r)}
+}
+
+type yamlDecoder struct {
+	decoder *yaml.Decoder
+}
+
+func (y yamlDecoder) DecodeConfig(into *Nurse) error {
+	return y.decoder.Decode(into)
+}

config/endpoints.go

@@ -0,0 +1,42 @@
+package config
+
+import (
+	"encoding"
+	"fmt"
+	"path"
+	"strings"
+	"time"
+
+	"github.com/baez90/nurse/grammar"
+)
+
+var _ encoding.TextUnmarshaler = (*EndpointSpec)(nil)
+
+type Route string
+
+func (r Route) String() string {
+	val := string(r)
+	val = strings.Trim(val, "/")
+
+	return path.Clean(fmt.Sprintf("/%s", val))
+}
+
+type EndpointSpec struct {
+	CheckTimeout time.Duration
+	Checks       []grammar.Check
+}
+
+func (e *EndpointSpec) UnmarshalText(text []byte) error {
+	parser, err := grammar.NewParser[grammar.Script]()
+	if err != nil {
+		return err
+	}
+
+	script, err := parser.Parse(string(text))
+	if err != nil {
+		return err
+	}
+
+	e.Checks = script.Checks
+	return nil
+}

config/env.go

@@ -0,0 +1,61 @@
+package config
+
+import (
+	"os"
+	"path"
+	. "strings"
+)
+
+const (
+	ServerKeyPrefix   = "NURSE_SERVER"
+	EndpointKeyPrefix = "NURSE_ENDPOINT"
+)
+
+func ServersFromEnv() (map[string]Server, error) {
+	servers := make(map[string]Server)
+	for _, kv := range os.Environ() {
+		key, value, valid := Cut(kv, "=")
+		if !valid {
+			continue
+		}
+
+		if !HasPrefix(key, ServerKeyPrefix) {
+			continue
+		}
+
+		serverName := ToLower(Trim(Replace(key, ServerKeyPrefix, "", -1), "_"))
+		srv := Server{}
+		if err := srv.UnmarshalURL(value); err != nil {
+			return nil, err
+		}
+
+		servers[serverName] = srv
+	}
+
+	return servers, nil
+}
+
+func EndpointsFromEnv() (map[Route]EndpointSpec, error) {
+	endpoints := make(map[Route]EndpointSpec)
+
+	for _, kv := range os.Environ() {
+		key, value, valid := Cut(kv, "=")
+		if !valid {
+			continue
+		}
+
+		if !HasPrefix(key, EndpointKeyPrefix) {
+			continue
+		}
+
+		endpointRoute := path.Join(Split(ToLower(Trim(Replace(key, EndpointKeyPrefix, "", -1), "_")), "_")...)
+		spec := EndpointSpec{}
+		if err := spec.UnmarshalText([]byte(value)); err != nil {
+			return nil, err
+		}
+
+		endpoints[Route(endpointRoute)] = spec
+	}
+
+	return endpoints, nil
+}

config/env_test.go

@@ -0,0 +1,162 @@
+package config_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/maxatome/go-testdeep/td"
+
+	"github.com/baez90/nurse/config"
+)
+
+//nolint:paralleltest // not possible with env setup
+func TestServersFromEnv(t *testing.T) {
+	tests := []struct {
+		name    string
+		env     map[string]string
+		want    any
+		wantErr bool
+	}{
+		{
+			name: "Empty env",
+			want: td.NotNil(),
+		},
+		{
+			name: "Single server",
+			env: map[string]string{
+				fmt.Sprintf("%s_REDIS_1", config.ServerKeyPrefix): "redis://localhost:6379",
+			},
+			want: td.Map(make(map[string]config.Server), td.MapEntries{
+				"redis_1": config.Server{
+					Type:  config.ServerTypeRedis,
+					Hosts: []string{"localhost:6379"},
+					Args:  make(map[string]any),
+				},
+			}),
+			wantErr: false,
+		},
+		{
+			name: "Multiple servers",
+			env: map[string]string{
+				fmt.Sprintf("%s_REDIS_1", config.ServerKeyPrefix): "redis://localhost:6379",
+				fmt.Sprintf("%s_REDIS_2", config.ServerKeyPrefix): "redis://redis:6379",
+			},
+			want: td.Map(make(map[string]config.Server), td.MapEntries{
+				"redis_1": config.Server{
+					Type:  config.ServerTypeRedis,
+					Hosts: []string{"localhost:6379"},
+					Args:  make(map[string]any),
+				},
+				"redis_2": config.Server{
+					Type:  config.ServerTypeRedis,
+					Hosts: []string{"redis:6379"},
+					Args:  make(map[string]any),
+				},
+			}),
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.env != nil {
+				for k, v := range tt.env {
+					t.Setenv(k, v)
+				}
+			}
+
+			got, err := config.ServersFromEnv()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ServersFromEnv() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			td.Cmp(t, got, tt.want)
+		})
+	}
+}
+
+//nolint:paralleltest // not possible with env setup
+func TestEndpointsFromEnv(t *testing.T) {
+	tests := []struct {
+		name    string
+		env     map[string]string
+		want    any
+		wantErr bool
+	}{
+		{
+			name: "Empty env",
+			want: td.NotNil(),
+		},
+		{
+			name: "Single endpoint",
+			env: map[string]string{
+				fmt.Sprintf("%s_readiness", config.EndpointKeyPrefix): `redis.PING("local_redis")`,
+			},
+			want: td.Map(make(map[config.Route]config.EndpointSpec), td.MapEntries{
+				config.Route("readiness"): td.Struct(config.EndpointSpec{}, td.StructFields{
+					"Checks": td.Len(1),
+				}),
+			}),
+			wantErr: false,
+		},
+		{
+			name: "Single endpoint - multiple checks",
+			env: map[string]string{
+				fmt.Sprintf("%s_readiness", config.EndpointKeyPrefix): `redis.PING("local_redis");redis.GET("local_redis", "serving") => String("ok")`,
+			},
+			want: td.Map(make(map[config.Route]config.EndpointSpec), td.MapEntries{
+				config.Route("readiness"): td.Struct(config.EndpointSpec{}, td.StructFields{
+					"Checks": td.Len(2),
+				}),
+			}),
+			wantErr: false,
+		},
+		{
+			name: "Single endpoint - sub-route",
+			env: map[string]string{
+				fmt.Sprintf("%s_READINESS_REDIS", config.EndpointKeyPrefix): `redis.PING("local_redis");redis.GET("local_redis", "serving") => String("ok")`,
+			},
+			want: td.Map(make(map[config.Route]config.EndpointSpec), td.MapEntries{
+				config.Route("readiness/redis"): td.Struct(config.EndpointSpec{}, td.StructFields{
+					"Checks": td.Len(2),
+				}),
+			}),
+			wantErr: false,
+		},
+		{
+			name: "Multiple endpoints",
+			env: map[string]string{
+				fmt.Sprintf("%s_readiness", config.EndpointKeyPrefix): `redis.PING("local_redis")`,
+				fmt.Sprintf("%s_liveness", config.EndpointKeyPrefix):  `redis.GET("local_redis", "serving") => String("ok")`,
+			},
+			want: td.Map(make(map[config.Route]config.EndpointSpec), td.MapEntries{
+				config.Route("readiness"): td.Struct(config.EndpointSpec{}, td.StructFields{
+					"Checks": td.Len(1),
+				}),
+				config.Route("liveness"): td.Struct(config.EndpointSpec{}, td.StructFields{
+					"Checks": td.Len(1),
+				}),
+			}),
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.env != nil {
+				for k, v := range tt.env {
+					t.Setenv(k, v)
+				}
+			}
+
+			got, err := config.EndpointsFromEnv()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("EndpointsFromEnv() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			td.Cmp(t, got, tt.want)
+		})
+	}
+}

config/flags.go

@@ -0,0 +1,39 @@
+package config
+
+import (
+	"flag"
+	"os"
+	"time"
+)
+
+const defaultCheckTimeout = 500 * time.Millisecond
+
+func ConfigureFlags(cfg *Nurse) *flag.FlagSet {
+	set := flag.NewFlagSet("nurse", flag.ContinueOnError)
+
+	set.DurationVar(
+		&cfg.CheckTimeout,
+		"check-timeout",
+		LookupEnvOr("NURSE_CHECK_TIMEOUT", defaultCheckTimeout, time.ParseDuration),
+		"Timeout when running checks",
+	)
+
+	return set
+}
+
+func LookupEnvOr[T any](envKey string, fallback T, parse func(envVal string) (T, error)) T {
+	envVal := os.Getenv(envKey)
+	if envVal == "" {
+		return fallback
+	}
+
+	if parsed, err := parse(envVal); err != nil {
+		return fallback
+	} else {
+		return parsed
+	}
+}
+
+func Identity[T any](in T) (T, error) {
+	return in, nil
+}

config/lookup.go

@@ -10,17 +10,26 @@ import (
 var (
 	ErrServerNameAlreadyRegistered = errors.New("server name is already registered")
 	ErrNoSuchServer                = errors.New("no known server with given name")
-	DefaultLookup                  = &ServerLookup{
+
-		servers: make(map[string]Server),
+	_ ServerLookup = (*ServerRegister)(nil)
-	}
 )
 
-type ServerLookup struct {
+type ServerLookup interface {
+	Lookup(name string) (*Server, error)
+}
+
+func NewServerRegister() *ServerRegister {
+	return &ServerRegister{
+		servers: make(map[string]Server),
+	}
+}
+
+type ServerRegister struct {
 	lock    sync.RWMutex
 	servers map[string]Server
 }
 
-func (l *ServerLookup) Register(name string, srv Server) error {
+func (l *ServerRegister) Register(name string, srv Server) error {
 	l.lock.Lock()
 	defer l.lock.Unlock()
 
@@ -34,7 +43,7 @@ func (l *ServerLookup) Register(name string, srv Server) error {
 	return nil
 }
 
-func (l *ServerLookup) Lookup(name string) (*Server, error) {
+func (l *ServerRegister) Lookup(name string) (*Server, error) {
 	l.lock.RLock()
 	defer l.lock.RUnlock()
 

config/options.go

@@ -0,0 +1,119 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+
+	"go.uber.org/zap"
+)
+
+func WithServersFromEnv() Option {
+	return OptionFunc(func(n Nurse) (Nurse, error) {
+		envServers, err := ServersFromEnv()
+		if err != nil {
+			return Nurse{}, err
+		}
+
+		if n.Servers == nil || len(n.Servers) == 0 {
+			n.Servers = envServers
+			return n, nil
+		}
+
+		for name, srv := range envServers {
+			if _, ok := n.Servers[name]; !ok {
+				n.Servers[name] = srv
+			}
+		}
+
+		return n, nil
+	})
+}
+
+func WithEndpointsFromEnv() Option {
+	return OptionFunc(func(n Nurse) (Nurse, error) {
+		envEndpoints, err := EndpointsFromEnv()
+		if err != nil {
+			return Nurse{}, err
+		}
+
+		if n.Endpoints == nil || len(n.Endpoints) == 0 {
+			n.Endpoints = envEndpoints
+			return n, nil
+		}
+
+		for route, spec := range envEndpoints {
+			if _, ok := n.Endpoints[route]; !ok {
+				n.Endpoints[route] = spec
+			}
+		}
+
+		return n, nil
+	})
+}
+
+func WithValuesFrom(other Nurse) Option {
+	return OptionFunc(func(n Nurse) (Nurse, error) {
+		return n.Merge(other), nil
+	})
+}
+
+func WithConfigFile(configFilePath string) Option {
+	logger := zap.L()
+	return OptionFunc(func(n Nurse) (Nurse, error) {
+		var out Nurse
+		if configFilePath != "" {
+			logger.Debug("Attempt to load config file")
+			if err := out.ReadFromFile(configFilePath); err == nil {
+				return out, nil
+			} else {
+				logger.Warn(
+					"Failed to load config file",
+					zap.String("config_file_path", configFilePath),
+					zap.Error(err),
+				)
+			}
+		}
+
+		if workingDir, err := os.Getwd(); err == nil {
+			configFilePath = filepath.Join(workingDir, "nurse.yaml")
+			logger.Debug("Attempt to load config file from current working directory")
+			if err = out.ReadFromFile(configFilePath); err == nil {
+				return out, nil
+			} else {
+				logger.Warn(
+					"Failed to load config file",
+					zap.String("config_file_path", configFilePath),
+					zap.Error(err),
+				)
+			}
+		}
+
+		if home, err := os.UserHomeDir(); err == nil {
+			configFilePath = filepath.Join(home, ".nurse.yaml")
+			logger.Debug("Attempt to load config file from user home directory")
+			if err = out.ReadFromFile(configFilePath); err == nil {
+				return out, nil
+			} else {
+				logger.Warn(
+					"Failed to load config file",
+					zap.String("config_file_path", configFilePath),
+					zap.Error(err),
+				)
+			}
+		}
+
+		configFilePath = filepath.Join("", "etc", "nurse", "config.yaml")
+		logger.Debug("Attempt to load config file from global config directory")
+		if err := out.ReadFromFile(configFilePath); err == nil {
+			return out, nil
+		} else {
+			logger.Warn(
+				"Failed to load config file",
+				zap.String("config_file_path", configFilePath),
+				zap.Error(err),
+			)
+		}
+
+		return Nurse{}, nil
+	})
+}

config/server.go

@@ -2,11 +2,13 @@ package config
 
 import (
 	"encoding/json"
+	"fmt"
 	"net/url"
 	"regexp"
 	"strings"
 
-	"github.com/baez90/nurse/internal/values"
+	"golang.org/x/exp/maps"
+	"gopkg.in/yaml.v3"
 )
 
 type ServerType uint
@@ -14,48 +16,42 @@ type ServerType uint
 const (
 	ServerTypeUnspecified ServerType = iota
 	ServerTypeRedis
+
+	//nolint:lll // cannot break regex
+	// language=regexp
+	urlSchemeRegex = `^(?P<scheme>\w+)://((?P<username>[\w-.]+)(:(?P<password>.*))?@)?(\{(?P<hosts>(.+:\d{1,5})(,(.+:\d{1,5}))*)}|(?P<host>.+:\d{1,5}))(?P<path>/.*$)?`
 )
 
-var hostsRegexp = regexp.MustCompile(`^{(.+:\d{1,5})(,(.+:\d{1,5}))*}|(.+:\d{1,5})$`)
+func (t ServerType) Scheme() string {
-
+	switch t {
-func ParseFromURL(url *url.URL) (*Server, error) {
+	case ServerTypeRedis:
-	srv := &Server{
+		return "redis"
-		Type:  SchemeToServerType(url.Scheme),
+	case ServerTypeUnspecified:
-		Hosts: hostsRegexp.FindAllString(url.Host, -1),
+		fallthrough
+	default:
+		return "unknown"
 	}
-
-	if user := url.User; user != nil {
-		srv.Credentials = &Credentials{
-			Username: user.Username(),
-		}
-		if pw, ok := user.Password(); ok {
-			srv.Credentials.Password = values.StringP(pw)
-		}
-	}
-
-	srv.Path = strings.Split(strings.Trim(url.EscapedPath(), "/"), "/")
-
-	q := url.Query()
-	qm := map[string][]string(q)
-	srv.Args = make(map[string]any, len(qm))
-
-	for k := range qm {
-		var val any
-		if err := json.Unmarshal([]byte(q.Get(k)), &val); err != nil {
-			return nil, err
-		} else {
-			srv.Args[k] = val
-		}
-	}
-
-	return srv, nil
 }
 
+var hostsRegexp = regexp.MustCompile(urlSchemeRegex)
+
 type Credentials struct {
 	Username string
 	Password *string
 }
 
+var (
+	_ json.Unmarshaler = (*Server)(nil)
+	_ yaml.Unmarshaler = (*Server)(nil)
+)
+
+type marshaledServer struct {
+	Type  ServerType
+	URL   string
+	Hosts []string
+	Args  map[string]any
+}
+
 type Server struct {
 	Type        ServerType
 	Credentials *Credentials
@@ -63,3 +59,135 @@ type Server struct {
 	Path        []string
 	Args        map[string]any
 }
+
+func (s *Server) UnmarshalYAML(value *yaml.Node) error {
+	s.Args = make(map[string]any)
+
+	tmp := new(marshaledServer)
+
+	if err := value.Decode(tmp); err != nil {
+		return err
+	}
+
+	return s.mergedMarshaledServer(*tmp)
+}
+
+func (s *Server) UnmarshalJSON(bytes []byte) error {
+	s.Args = make(map[string]any)
+
+	tmp := new(marshaledServer)
+
+	if err := json.Unmarshal(bytes, tmp); err != nil {
+		return err
+	}
+
+	return s.mergedMarshaledServer(*tmp)
+}
+
+func (s *Server) UnmarshalURL(rawUrl string) error {
+	rawPath, username, password, err := s.extractBaseProperties(rawUrl)
+	if err != nil {
+		return err
+	}
+
+	if username != "" {
+		s.Credentials = &Credentials{
+			Username: username,
+		}
+		if password != "" {
+			s.Credentials.Password = &password
+		}
+	}
+
+	if rawPath != "" {
+		parsedUrl, err := url.Parse(fmt.Sprintf("%s://%s%s", s.Type.Scheme(), s.Hosts[0], rawPath))
+		if err != nil {
+			return err
+		}
+		if err = s.unmarshalPath(parsedUrl); err != nil {
+			return err
+		}
+	} else {
+		s.Args = make(map[string]any)
+	}
+
+	return nil
+}
+
+func (s *Server) extractBaseProperties(rawUrl string) (rawPath, username, password string, err error) {
+	allMatches := hostsRegexp.FindAllStringSubmatch(rawUrl, -1)
+	if matchLen := len(allMatches); matchLen != 1 {
+		return "", "", "", fmt.Errorf("ambiguous server match: %d", matchLen)
+	}
+
+	match := allMatches[0]
+
+	for i, name := range hostsRegexp.SubexpNames() {
+		if i == 0 {
+			continue
+		}
+
+		switch name {
+		case "scheme":
+			s.Type = SchemeToServerType(match[i])
+		case "host":
+			singleHost := match[i]
+			if singleHost != "" {
+				s.Hosts = []string{singleHost}
+			}
+		case "hosts":
+			hosts := strings.Split(match[i], ",")
+			for _, host := range hosts {
+				s.Hosts = append(s.Hosts, strings.TrimSpace(host))
+			}
+		case "path":
+			rawPath = match[i]
+		case "username":
+			username = match[i]
+		case "password":
+			password = match[i]
+		}
+	}
+
+	return rawPath, username, password, nil
+}
+
+func (s *Server) unmarshalPath(u *url.URL) error {
+	s.Path = strings.Split(strings.Trim(u.EscapedPath(), "/"), "/")
+
+	q := u.Query()
+	qm := map[string][]string(q)
+	s.Args = make(map[string]any, len(qm))
+
+	for k := range qm {
+		var val any
+		if err := json.Unmarshal([]byte(q.Get(k)), &val); err != nil {
+			return err
+		} else {
+			s.Args[k] = val
+		}
+	}
+
+	return nil
+}
+
+func (s *Server) mergedMarshaledServer(srv marshaledServer) error {
+	if srv.URL != "" {
+		if err := s.UnmarshalURL(srv.URL); err != nil {
+			return err
+		}
+
+		if srv.Args != nil {
+			maps.Copy(s.Args, srv.Args)
+		}
+		return nil
+	}
+
+	s.Type = srv.Type
+	s.Hosts = srv.Hosts
+	if srv.Args != nil {
+		s.Args = srv.Args
+	}
+
+	return nil
+}

config/server_test.go

@@ -0,0 +1,144 @@
+package config_test
+
+import (
+	"testing"
+
+	"github.com/maxatome/go-testdeep/td"
+
+	"github.com/baez90/nurse/config"
+	"github.com/baez90/nurse/internal/values"
+)
+
+func TestParseFromURL(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name    string
+		url     string
+		want    any
+		wantErr bool
+	}{
+		{
+			name: "Single Redis server",
+			url:  "redis://localhost:6379/0",
+			want: &config.Server{
+				Type:  config.ServerTypeRedis,
+				Hosts: []string{"localhost:6379"},
+				Path:  []string{"0"},
+				Args:  make(map[string]any),
+			},
+		},
+		{
+			name: "Single Redis server with args",
+			url:  "redis://localhost:6379/0?MaxRetries=3",
+			want: &config.Server{
+				Type:  config.ServerTypeRedis,
+				Hosts: []string{"localhost:6379"},
+				Path:  []string{"0"},
+				Args: map[string]any{
+					"MaxRetries": 3.0,
+				},
+			},
+		},
+		{
+			name: "Single Redis server with user",
+			url:  "redis://user@localhost:6379/0",
+			want: &config.Server{
+				Type:  config.ServerTypeRedis,
+				Hosts: []string{"localhost:6379"},
+				Path:  []string{"0"},
+				Args:  make(map[string]any),
+				Credentials: &config.Credentials{
+					Username: "user",
+				},
+			},
+		},
+		{
+			name: "Single Redis server with credentials",
+			url:  "redis://user:p4$$w0rd@localhost:6379/0",
+			want: &config.Server{
+				Type:  config.ServerTypeRedis,
+				Hosts: []string{"localhost:6379"},
+				Path:  []string{"0"},
+				Args:  make(map[string]any),
+				Credentials: &config.Credentials{
+					Username: "user",
+					Password: values.StringP("p4$$w0rd"),
+				},
+			},
+		},
+		{
+			name: "Multiple Redis servers",
+			url:  "redis://{localhost:6379,localhost:6380}/0",
+			want: &config.Server{
+				Type: config.ServerTypeRedis,
+				Hosts: []string{
+					"localhost:6379",
+					"localhost:6380",
+				},
+				Path: []string{"0"},
+				Args: make(map[string]any),
+			},
+		},
+		{
+			name: "Multiple Redis servers with args",
+			url:  "redis://{localhost:6379,localhost:6380}/0?MaxRetries=3",
+			want: &config.Server{
+				Type: config.ServerTypeRedis,
+				Hosts: []string{
+					"localhost:6379",
+					"localhost:6380",
+				},
+				Path: []string{"0"},
+				Args: map[string]any{
+					"MaxRetries": 3.0,
+				},
+			},
+		},
+		{
+			name: "Multiple Redis servers with user",
+			url:  "redis://user@{localhost:6379,localhost:6380}/0",
+			want: &config.Server{
+				Type: config.ServerTypeRedis,
+				Hosts: []string{
+					"localhost:6379",
+					"localhost:6380",
+				},
+				Credentials: &config.Credentials{
+					Username: "user",
+				},
+				Path: []string{"0"},
+				Args: make(map[string]any),
+			},
+		},
+		{
+			name: "Multiple Redis servers with credentials",
+			url:  "redis://user:p4$$w0rd@{localhost:6379,localhost:6380}/0",
+			want: &config.Server{
+				Type: config.ServerTypeRedis,
+				Hosts: []string{
+					"localhost:6379",
+					"localhost:6380",
+				},
+				Credentials: &config.Credentials{
+					Username: "user",
+					Password: values.StringP("p4$$w0rd"),
+				},
+				Path: []string{"0"},
+				Args: make(map[string]any),
+			},
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			got := new(config.Server)
+
+			if err := got.UnmarshalURL(tt.url); (err != nil) != tt.wantErr {
+				t.Errorf("ParseFromURL() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			td.Cmp(t, got, tt.want)
+		})
+	}
+}

go.mod

@@ -5,9 +5,12 @@ go 1.18
 require (
 	github.com/alecthomas/participle/v2 v2.0.0-alpha8
 	github.com/go-redis/redis/v8 v8.11.5
+	github.com/google/uuid v1.3.0
 	github.com/maxatome/go-testdeep v1.11.0
-	github.com/mitchellh/mapstructure v1.4.3
+	github.com/mitchellh/mapstructure v1.5.0
 	github.com/testcontainers/testcontainers-go v0.13.0
+	go.uber.org/zap v1.10.0
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )
 
 require (
@@ -27,7 +30,6 @@ require (
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
-	github.com/google/uuid v1.3.0 // indirect
 	github.com/magiconair/properties v1.8.6 // indirect
 	github.com/moby/sys/mount v0.3.2 // indirect
 	github.com/moby/sys/mountinfo v0.6.1 // indirect
@@ -39,10 +41,12 @@ require (
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/sirupsen/logrus v1.8.1 // indirect
 	go.opencensus.io v0.23.0 // indirect
+	go.uber.org/atomic v1.4.0 // indirect
+	go.uber.org/multierr v1.1.0 // indirect
+	golang.org/x/exp v0.0.0-20220428152302-39d4317da171 // indirect
 	golang.org/x/net v0.0.0-20220420153159-1850ba15e1be // indirect
 	golang.org/x/sys v0.0.0-20220412211240-33da011f77ad // indirect
 	google.golang.org/genproto v0.0.0-20220414192740-2d67ff6cf2b4 // indirect
 	google.golang.org/grpc v1.45.0 // indirect
 	google.golang.org/protobuf v1.28.0 // indirect
-	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )

go.sum

@@ -500,8 +500,8 @@ github.com/miekg/pkcs11 v1.0.3/go.mod h1:XsNlhZGX73bx86s2hdc/FuaLm2CPZJemRLMA+WT
 github.com/mistifyio/go-zfs v2.1.2-0.20190413222219-f784269be439+incompatible/go.mod h1:8AuVvqP/mXw1px98n46wfvcGfQ4ci2FwoAjKYxuo3Z4=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/mapstructure v1.1.2/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
-github.com/mitchellh/mapstructure v1.4.3 h1:OVowDSCllw/YjdLkam3/sm7wEtOy59d8ndGgCcyj8cs=
+github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
-github.com/mitchellh/mapstructure v1.4.3/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
+github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
 github.com/mitchellh/osext v0.0.0-20151018003038-5e2d6d41470f/go.mod h1:OkQIRizQZAeMln+1tSwduZz7+Af5oFlKirV/MSYes2A=
 github.com/moby/locker v1.0.1/go.mod h1:S7SDdo5zpBK84bzzVlKr2V0hz+7x9hWbYC/kq7oQppc=
 github.com/moby/sys/mount v0.2.0/go.mod h1:aAivFE2LB3W4bACsUXChRHQ0qKWsetY4Y9V7sxOougM=
@@ -717,9 +717,12 @@ go.opencensus.io v0.23.0 h1:gqCw0LfLxScz8irSi8exQc7fyQ0fKQU/qnC/X8+V/1M=
 go.opencensus.io v0.23.0/go.mod h1:XItmlyltB5F7CS4xOC1DcqMoFqwtC6OG2xF7mCv7P7E=
 go.opentelemetry.io/proto/otlp v0.7.0/go.mod h1:PqfVotwruBrMGOCsRd/89rSnXhoiJIqeYNgFYFoEGnI=
 go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
+go.uber.org/atomic v1.4.0 h1:cxzIVoETapQEqDhQu3QfnvXAV4AlzcvUCxkVUFw3+EU=
 go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/goleak v1.1.12/go.mod h1:cwTWslyiVhfpKIDGSZEM2HlOvcqm+tG4zioyIeLoqMQ=
+go.uber.org/multierr v1.1.0 h1:HoEmRHQPVSqub6w2z2d2EOVs2fjyFRGyofhKuyDq0QI=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
+go.uber.org/zap v1.10.0 h1:ORx85nbTijNz8ljznvCMR1ZBIPKFn3jQrag10X2AsuM=
 go.uber.org/zap v1.10.0/go.mod h1:vwi/ZaCAaUcBkycHslxD9B2zi4UTXhF60s6SWpuDF0Q=
 golang.org/x/crypto v0.0.0-20171113213409-9f005a07e0d3/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
@@ -744,6 +747,8 @@ golang.org/x/exp v0.0.0-20191227195350-da58074b4299/go.mod h1:2RIsYlXP63K8oxa1u0
 golang.org/x/exp v0.0.0-20200119233911-0405dc783f0a/go.mod h1:2RIsYlXP63K8oxa1u096TMicItID8zy7Y6sNkU49FU4=
 golang.org/x/exp v0.0.0-20200207192155-f17229e696bd/go.mod h1:J/WKrq2StrnmMY6+EHIKF9dgMWnmCNThgcyBT1FY9mM=
 golang.org/x/exp v0.0.0-20200224162631-6cc2880d07d6/go.mod h1:3jZMyOhIsHpP37uCMkUooju7aAi5cS1Q23tOzKc+0MU=
+golang.org/x/exp v0.0.0-20220428152302-39d4317da171 h1:TfdoLivD44QwvssI9Sv1xwa5DcL5XQr4au4sZ2F2NV4=
+golang.org/x/exp v0.0.0-20220428152302-39d4317da171/go.mod h1:lgLbSvA5ygNOMpwM/9anMpWVlVJ7Z+cHWq/eFuinpGE=
 golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
 golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=

grammar/grammar.go

@@ -1,9 +1,5 @@
 package grammar
 
-type CheckUnmarshaler interface {
-	UnmarshalCheck(c Check) error
-}
-
 type Call struct {
 	Module string  `parser:"(@Module'.')?"`
 	Name   string  `parser:"@Ident"`
@@ -20,5 +16,5 @@ type Check struct {
 }
 
 type Script struct {
-	Checks []Check `parser:"@@*"`
+	Checks []Check `parser:"(@@';'?)*"`
 }

main.go

@@ -1,28 +1,66 @@
 package main
 
 import (
+	"log"
 	"os"
-	"time"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+
+	"github.com/baez90/nurse/config"
 )
 
-var checkTimeout time.Duration
+var (
+	logLevel = zapcore.InfoLevel
+	cfgFile  string
+	cfg      config.Nurse
+)
 
 func main() {
-}
+	if err := prepareFlags(); err != nil {
+		log.Fatalf("Failed to parse flags: %v", err)
+	}
+	setupLogging()
 
-func lookupEnvOr[T any](envKey string, fallback T, parse func(envVal string) (T, error)) T {
+	logger := zap.L()
-	envVal := os.Getenv(envKey)
+
-	if envVal == "" {
+	envCfg, err := config.New(
-		return fallback
+		config.WithValuesFrom(cfg),
+		config.WithConfigFile(cfgFile),
+		config.WithServersFromEnv(),
+		config.WithEndpointsFromEnv(),
+	)
+
+	if err != nil {
+		logger.Error("Failed to load config from environment", zap.Error(err))
+		os.Exit(1)
 	}
 
-	if parsed, err := parse(envVal); err != nil {
+	logger.Debug("Loaded config", zap.Any("config", envCfg))
-		return fallback
-	} else {
-		return parsed
-	}
 }
 
-func identity[T any](in T) (T, error) {
+func setupLogging() {
-	return in, nil
+	cfg := zap.NewProductionConfig()
+	cfg.Level = zap.NewAtomicLevelAt(logLevel)
+	logger, err := cfg.Build()
+	if err != nil {
+		log.Fatalf("Failed to setup logging: %v", err)
+	}
+
+	zap.ReplaceGlobals(logger)
+}
+
+func prepareFlags() error {
+	set := config.ConfigureFlags(&cfg)
+
+	set.Var(&logLevel, "log-level", "Log level to use")
+
+	set.StringVar(
+		&cfgFile,
+		"config",
+		config.LookupEnvOr[string]("NURSE_CONFIG", "", config.Identity[string]),
+		"Config file to load, if not set $HOME/.nurse.yaml, /etc/nurse/config.yaml and ./nurse.yaml are tried  - optional",
+	)
+
+	return set.Parse(os.Args)
 }

nurse.yaml

@@ -0,0 +1,16 @@
+checkTimeout: 500ms
+servers:
+  redis_local:
+    url: redis://localhost:6379/0
+    args:
+      MaxRetries: 3
+
+endpoints:
+  /ready:
+    checkTimeout: 500ms
+    checks:
+      - redis.PING("redis_local")
+  /liveness:
+    checkTimeout: 100ms
+    checks:
+      - redis.GET("redis_local", "running") => String("ok")

redis/checks.go

@@ -1,35 +1,18 @@
 package redis
 
 import (
-	"fmt"
-	"strings"
-
 	"github.com/baez90/nurse/check"
-	"github.com/baez90/nurse/grammar"
 )
 
-var knownChecks = map[string]func() check.SystemChecker{
+func Module() *check.Module {
-	"ping": func() check.SystemChecker {
+	m, _ := check.NewModule(
-		return new(PingCheck)
+		check.WithCheck("ping", check.FactoryFunc(func() check.SystemChecker {
-	},
+			return new(PingCheck)
-	"get": func() check.SystemChecker {
+		})),
-		return new(GetCheck)
+		check.WithCheck("get", check.FactoryFunc(func() check.SystemChecker {
-	},
+			return new(GetCheck)
-}
+		})),
-
-func LookupCheck(c grammar.Check) (check.SystemChecker, error) {
-	var (
-		provider func() check.SystemChecker
-		ok       bool
 	)
-	if provider, ok = knownChecks[strings.ToLower(c.Initiator.Name)]; !ok {
-		return nil, fmt.Errorf("%w: %s", check.ErrNoSuchCheck, c.Initiator.Name)
-	}
 
-	chk := provider()
+	return m
-	if err := chk.UnmarshalCheck(c); err != nil {
-		return nil, err
-	}
-
-	return chk, nil
 }

redis/checks_test.go

@@ -0,0 +1,103 @@
+package redis_test
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"testing"
+
+	redisCli "github.com/go-redis/redis/v8"
+	"github.com/google/uuid"
+	"github.com/maxatome/go-testdeep/td"
+
+	"github.com/baez90/nurse/config"
+	"github.com/baez90/nurse/grammar"
+	"github.com/baez90/nurse/redis"
+)
+
+func TestChecks_Execute(t *testing.T) {
+	t.Parallel()
+
+	redisModule := redis.Module()
+
+	tests := []struct {
+		name    string
+		check   string
+		setup   func(tb testing.TB, cli redisCli.UniversalClient)
+		wantErr bool
+	}{
+		{
+			name:  "Get value",
+			check: `redis.GET("%s", "some_key")`,
+			setup: func(tb testing.TB, cli redisCli.UniversalClient) {
+				tb.Helper()
+				td.CmpNoError(tb, cli.Set(context.Background(), "some_key", "some_value", 0).Err())
+			},
+			wantErr: false,
+		},
+		{
+			name:  "Get value - validate value",
+			check: `redis.GET("%s", "some_key") => String("some_value")`,
+			setup: func(tb testing.TB, cli redisCli.UniversalClient) {
+				tb.Helper()
+				td.CmpNoError(tb, cli.Set(context.Background(), "some_key", "some_value", 0).Err())
+			},
+			wantErr: false,
+		},
+		{
+			name:    "PING check",
+			check:   `redis.PING("%s")`,
+			wantErr: false,
+		},
+		{
+			name:    "PING check - with custom message",
+			check:   `redis.PING("%s", "Hello, Redis!")`,
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			srv := PrepareRedisContainer(t)
+			serverName := uuid.NewString()
+
+			register := config.NewServerRegister()
+
+			if err := register.Register(serverName, *srv); err != nil {
+				t.Fatalf("DefaultLookup.Register() err = %v", err)
+			}
+
+			cli, err := redis.ClientForServer(srv)
+			if err != nil {
+				t.Fatalf("redis.ClientForServer() err = %v", err)
+			}
+
+			if tt.setup != nil {
+				tt.setup(t, cli)
+			}
+
+			if strings.Contains(tt.check, "%s") {
+				tt.check = fmt.Sprintf(tt.check, serverName)
+			}
+
+			parser, err := grammar.NewParser[grammar.Check]()
+			td.CmpNoError(t, err, "grammar.NewParser()")
+			parsedCheck, err := parser.Parse(tt.check)
+			td.CmpNoError(t, err, "parser.Parse()")
+
+			chk, err := redisModule.Lookup(*parsedCheck, register)
+			td.CmpNoError(t, err, "redis.LookupCheck()")
+
+			td.CmpNoError(t, chk.UnmarshalCheck(*parsedCheck, register), "get.UnmarshalCheck()")
+			td.CmpNoError(t, chk.Execute(context.Background()))
+
+			if tt.wantErr {
+				td.CmpError(t, chk.Execute(context.Background()))
+			} else {
+				td.CmpNoError(t, chk.Execute(context.Background()))
+			}
+		})
+	}
+}

redis/client.go

@@ -10,10 +10,10 @@ import (
 	"github.com/baez90/nurse/grammar"
 )
 
-func clientFromParam(p grammar.Param) (redis.UniversalClient, error) {
+func clientFromParam(p grammar.Param, srvLookup config.ServerLookup) (redis.UniversalClient, error) {
 	if srvName, err := p.AsString(); err != nil {
 		return nil, err
-	} else if srv, err := config.DefaultLookup.Lookup(srvName); err != nil {
+	} else if srv, err := srvLookup.Lookup(srvName); err != nil {
 		return nil, err
 	} else if redisCli, err := ClientForServer(srv); err != nil {
 		return nil, err
@@ -37,5 +37,10 @@ func ClientForServer(srv *config.Server) (redis.UniversalClient, error) {
 		return nil, err
 	}
 
+	if srv.Credentials != nil {
+		opts.Username = srv.Credentials.Username
+		opts.Password = *srv.Credentials.Password
+	}
+
 	return redis.NewUniversalClient(opts), nil
 }

redis/container_test.go

@@ -3,19 +3,16 @@ package redis_test
 import (
 	"context"
 	"fmt"
-	"net/url"
 	"testing"
 	"time"
 
 	"github.com/testcontainers/testcontainers-go"
-	"github.com/testcontainers/testcontainers-go/wait"
 
 	"github.com/baez90/nurse/config"
 )
 
 func PrepareRedisContainer(tb testing.TB) *config.Server {
 	tb.Helper()
-
 	const redisPort = "6379/tcp"
 
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
@@ -24,9 +21,9 @@ func PrepareRedisContainer(tb testing.TB) *config.Server {
 	container, err := testcontainers.GenericContainer(ctx, testcontainers.GenericContainerRequest{
 		ContainerRequest: testcontainers.ContainerRequest{
 			Image:        "docker.io/redis:alpine",
-			Name:         tb.Name(),
 			ExposedPorts: []string{redisPort},
-			WaitingFor:   wait.ForListeningPort(redisPort),
+			SkipReaper:   true,
+			AutoRemove:   true,
 		},
 		Started: true,
 		Logger:  testcontainers.TestLogger(tb),
@@ -46,13 +43,8 @@ func PrepareRedisContainer(tb testing.TB) *config.Server {
 		tb.Fatalf("container.PortEndpoint() err = %v", err)
 	}
 
-	u, err := url.Parse(fmt.Sprintf("%s/0?MaxRetries=3", ep))
+	srv := new(config.Server)
-	if err != nil {
+	if err := srv.UnmarshalURL(fmt.Sprintf("%s/0?MaxRetries=3", ep)); err != nil {
-		tb.Fatalf("url.Parse() err = %v", err)
-	}
-
-	srv, err := config.ParseFromURL(u)
-	if err != nil {
 		tb.Fatalf("config.ParseFromURL() err = %v", err)
 	}
 	return srv

redis/get.go

@@ -6,13 +6,11 @@ import (
 	"github.com/go-redis/redis/v8"
 
 	"github.com/baez90/nurse/check"
+	"github.com/baez90/nurse/config"
 	"github.com/baez90/nurse/grammar"
 )
 
-var (
+var _ check.SystemChecker = (*GetCheck)(nil)
-	_ check.SystemChecker      = (*GetCheck)(nil)
-	_ grammar.CheckUnmarshaler = (*GetCheck)(nil)
-)
 
 type GetCheck struct {
 	redis.UniversalClient
@@ -30,7 +28,7 @@ func (g GetCheck) Execute(ctx context.Context) error {
 	return g.validators.Validate(cmd)
 }
 
-func (g *GetCheck) UnmarshalCheck(c grammar.Check) error {
+func (g *GetCheck) UnmarshalCheck(c grammar.Check, lookup config.ServerLookup) error {
 	const serverAndKeyArgsNumber = 2
 	inst := c.Initiator
 	if err := grammar.ValidateParameterCount(inst.Params, serverAndKeyArgsNumber); err != nil {
@@ -38,7 +36,7 @@ func (g *GetCheck) UnmarshalCheck(c grammar.Check) error {
 	}
 
 	var err error
-	if g.UniversalClient, err = clientFromParam(inst.Params[0]); err != nil {
+	if g.UniversalClient, err = clientFromParam(inst.Params[0], lookup); err != nil {
 		return err
 	}
 
@@ -46,5 +44,9 @@ func (g *GetCheck) UnmarshalCheck(c grammar.Check) error {
 		return err
 	}
 
+	if g.validators, err = ValidatorsForFilters(c.Validators); err != nil {
+		return err
+	}
+
 	return nil
 }

redis/get_test.go

@@ -1,70 +0,0 @@
-package redis_test
-
-import (
-	"context"
-	"fmt"
-	"testing"
-
-	redisCli "github.com/go-redis/redis/v8"
-	"github.com/maxatome/go-testdeep/td"
-
-	"github.com/baez90/nurse/config"
-	"github.com/baez90/nurse/grammar"
-	"github.com/baez90/nurse/redis"
-)
-
-func TestGetCheck_Execute(t *testing.T) {
-	t.Parallel()
-	srv := PrepareRedisContainer(t)
-	if err := config.DefaultLookup.Register(t.Name(), *srv); err != nil {
-		t.Fatalf("DefaultLookup.Register() err = %v", err)
-	}
-
-	cli, err := redis.ClientForServer(srv)
-	if err != nil {
-		t.Fatalf("redis.ClientForServer() err = %v", err)
-	}
-
-	tests := []struct {
-		name    string
-		check   string
-		setup   func(tb testing.TB, cli redisCli.UniversalClient)
-		wantErr bool
-	}{
-		{
-			name:  "Get value",
-			check: fmt.Sprintf(`redis.GET("%s", "some_key")`, t.Name()),
-			setup: func(tb testing.TB, cli redisCli.UniversalClient) {
-				tb.Helper()
-				td.CmpNoError(tb, cli.Set(context.Background(), "some_key", "some_value", 0).Err())
-			},
-			wantErr: false,
-		},
-	}
-	for _, tt := range tests {
-		tt := tt
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-
-			if tt.setup != nil {
-				tt.setup(t, cli)
-			}
-
-			get := new(redis.GetCheck)
-
-			parser, err := grammar.NewParser[grammar.Check]()
-			td.CmpNoError(t, err, "grammar.NewParser()")
-			check, err := parser.Parse(tt.check)
-			td.CmpNoError(t, err, "parser.Parse()")
-
-			td.CmpNoError(t, get.UnmarshalCheck(*check), "get.UnmarshalCheck()")
-			td.CmpNoError(t, get.Execute(context.Background()))
-
-			if tt.wantErr {
-				td.CmpError(t, get.Execute(context.Background()))
-			} else {
-				td.CmpNoError(t, get.Execute(context.Background()))
-			}
-		})
-	}
-}

redis/ping.go

@@ -7,13 +7,11 @@ import (
 	"github.com/go-redis/redis/v8"
 
 	"github.com/baez90/nurse/check"
+	"github.com/baez90/nurse/config"
 	"github.com/baez90/nurse/grammar"
 )
 
-var (
+var _ check.SystemChecker = (*PingCheck)(nil)
-	_ check.SystemChecker      = (*PingCheck)(nil)
-	_ grammar.CheckUnmarshaler = (*PingCheck)(nil)
-)
 
 type PingCheck struct {
 	redis.UniversalClient
@@ -34,7 +32,7 @@ func (p PingCheck) Execute(ctx context.Context) error {
 	return nil
 }
 
-func (p *PingCheck) UnmarshalCheck(c grammar.Check) error {
+func (p *PingCheck) UnmarshalCheck(c grammar.Check, lookup config.ServerLookup) error {
 	const (
 		serverOnlyArgCount       = 1
 		serverAndMessageArgCount = 2
@@ -54,7 +52,7 @@ func (p *PingCheck) UnmarshalCheck(c grammar.Check) error {
 		}
 		fallthrough
 	case serverOnlyArgCount:
-		if cli, err := clientFromParam(init.Params[0]); err != nil {
+		if cli, err := clientFromParam(init.Params[0], lookup); err != nil {
 			return err
 		} else {
 			p.UniversalClient = cli

redis/ping_test.go

@@ -1,61 +0,0 @@
-package redis_test
-
-import (
-	"context"
-	"fmt"
-	"testing"
-
-	"github.com/maxatome/go-testdeep/td"
-
-	"github.com/baez90/nurse/config"
-	"github.com/baez90/nurse/grammar"
-	"github.com/baez90/nurse/redis"
-)
-
-func TestPingCheck_Execute(t *testing.T) {
-	t.Parallel()
-	srv := PrepareRedisContainer(t)
-	if err := config.DefaultLookup.Register(t.Name(), *srv); err != nil {
-		t.Fatalf("DefaultLookup.Register() err = %v", err)
-	}
-
-	tests := []struct {
-		name    string
-		check   string
-		wantErr bool
-	}{
-		{
-			name:    "PING check",
-			check:   fmt.Sprintf(`redis.PING("%s")`, t.Name()),
-			wantErr: false,
-		},
-		// redis.PING("my-redis")
-		// redis.PING("my-redis", "Hello, Redis!")
-		// redis.GET("my-redis", "some-key") -> String("Hello")
-		// redis.PING("my-redis"); redis.GET("my-redis", "some-key") -> String("Hello")
-		{
-			name:    "PING check - with custom message",
-			check:   fmt.Sprintf(`redis.PING("%s", "Hello, Redis!")`, t.Name()),
-			wantErr: false,
-		},
-	}
-	for _, tt := range tests {
-		tt := tt
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-			ping := new(redis.PingCheck)
-
-			parser, err := grammar.NewParser[grammar.Check]()
-			td.CmpNoError(t, err, "grammar.NewParser()")
-			check, err := parser.Parse(tt.check)
-			td.CmpNoError(t, err, "parser.Parse()")
-
-			if err := ping.UnmarshalCheck(*check); err != nil {
-				t.Fatalf("UnmarshalCheck() err = %v", err)
-			}
-			if err := ping.Execute(context.Background()); (err != nil) != tt.wantErr {
-				t.Errorf("Execute() error = %v, wantErr %v", err, tt.wantErr)
-			}
-		})
-	}
-}

redis/validation.go

@@ -3,23 +3,64 @@ package redis
 import (
 	"errors"
 	"fmt"
+	"strings"
 
 	"github.com/go-redis/redis/v8"
+
+	"github.com/baez90/nurse/check"
+	"github.com/baez90/nurse/grammar"
 )
 
 var (
+	ErrNoSuchValidator = errors.New("no such validator")
+
 	_ CmdValidator = (ValidationChain)(nil)
-	_ CmdValidator = StringCmdValidator("")
+	_ CmdValidator = (*StringCmdValidator)(nil)
+
+	knownValidators = map[string]func() unmarshallableCmdValidator{
+		"string": func() unmarshallableCmdValidator {
+			return new(StringCmdValidator)
+		},
+	}
 )
 
 type (
 	CmdValidator interface {
 		Validate(cmder redis.Cmder) error
 	}
-
+	unmarshallableCmdValidator interface {
-	ValidationChain []CmdValidator
+		CmdValidator
+		check.CallUnmarshaler
+	}
 )
 
+func ValidatorsForFilters(filters *grammar.Filters) (ValidationChain, error) {
+	if filters == nil || filters.Chain == nil {
+		return ValidationChain{}, nil
+	}
+	chain := make(ValidationChain, 0, len(filters.Chain))
+	for i := range filters.Chain {
+		validationCall := filters.Chain[i]
+		if validatorProvider, ok := knownValidators[strings.ToLower(validationCall.Name)]; !ok {
+			return nil, fmt.Errorf("%w: %s", ErrNoSuchValidator, validationCall.Name)
+		} else {
+			validator := validatorProvider()
+			if err := validator.UnmarshalCall(validationCall); err != nil {
+				return nil, err
+			}
+			chain = append(chain, validator)
+		}
+	}
+
+	return chain, nil
+}
+
+type ValidationChain []CmdValidator
+
+func (v ValidationChain) UnmarshalCall(grammar.Call) error {
+	return errors.New("cannot unmarshal chain")
+}
+
 func (v ValidationChain) Validate(cmder redis.Cmder) error {
 	for i := range v {
 		if err := v[i].Validate(cmder); err != nil {
@@ -32,6 +73,20 @@ func (v ValidationChain) Validate(cmder redis.Cmder) error {
 
 type StringCmdValidator string
 
+func (s *StringCmdValidator) UnmarshalCall(c grammar.Call) error {
+	if err := grammar.ValidateParameterCount(c.Params, 1); err != nil {
+		return err
+	}
+
+	want, err := c.Params[0].AsString()
+	if err != nil {
+		return err
+	}
+
+	*s = StringCmdValidator(want)
+	return nil
+}
+
 func (s StringCmdValidator) Validate(cmder redis.Cmder) error {
 	if err := cmder.Err(); err != nil {
 		return err