Refactoring for better separation of concerns

Makefile

@@ -1,15 +1,22 @@
-.PHONY: all build test docker
+.PHONY: all build build-sql test docker
 
 all: build test
 
 DOCKER_IMAGE := checkup
 
 build:
+	go fmt ./...
+	go mod tidy
 	mkdir -p builds/
 	go build -o builds/ ./cmd/...
 
+build-sql:
+	go fmt ./...
+	go mod tidy
+	go build -o builds/ -tags sql ./cmd/...
+
 test:
-	go test -race -count=1 -v ./...
+	go test -race -count=1 ./...
 
 docker:
 	docker build --no-cache . -t $(DOCKER_IMAGE)

README.md

@@ -11,7 +11,20 @@ Checkup was created by Matt Holt, author of the [Caddy web server](https://caddy
 
 This tool is a work-in-progress. Please use liberally (with discretion) and report any bugs!
 
+## Recent changes
 
+Due to recent development, some breaking changes have been introduced:
+
+- providers: the json config field `provider` was renamed to `type` for consistency,
+- notifiers: the json config field `name` was renamed to `type` for consistency,
+- sql: by default the sqlite storage engine is disabled (needs build with `-tags sql` to enable),
+
+If you want to build the latest version, it's best to run:
+
+- `make build` - builds checkup without sql support,
+- `make build-sql` - builds checkup with pgsql/sqlite;
+
+The resulting binary will be placed into `builds/checkup`.
 
 ## Intro
 
@@ -76,9 +89,9 @@ You can configure Checkup entirely with a simple JSON document. You should confi
 		// storage configuration goes here
 	},
 
-	"notifier": {
+	"notifiers": [
 		// notifier configuration goes here
-	}
+	]
 }
 ```
 
@@ -90,7 +103,7 @@ Here are the configuration structures you can use, which are explained fully [in
 
 #### HTTP Checkers
 
-**[godoc: HTTPChecker](https://godoc.org/github.com/sourcegraph/checkup#HTTPChecker)**
+**[godoc: HTTPChecker](https://godoc.org/github.com/sourcegraph/checkup/check/http)**
 
 ```js
 {
@@ -104,7 +117,7 @@ Here are the configuration structures you can use, which are explained fully [in
 
 #### TCP Checkers
 
-**[godoc: TCPChecker](https://godoc.org/github.com/sourcegraph/checkup#TCPChecker)**
+**[godoc: TCPChecker](https://godoc.org/github.com/sourcegraph/checkup/check/tcp)**
 
 ```js
 {
@@ -116,7 +129,7 @@ Here are the configuration structures you can use, which are explained fully [in
 
 #### DNS Checkers
 
-**[godoc: DNSChecker](https://godoc.org/github.com/sourcegraph/checkup#DNSChecker)**
+**[godoc: DNSChecker](https://godoc.org/github.com/sourcegraph/checkup/check/dns)**
 
 ```js
 {
@@ -129,7 +142,7 @@ Here are the configuration structures you can use, which are explained fully [in
 
 #### TLS Checkers
 
-**[godoc: TLSChecker](https://godoc.org/github.com/sourcegraph/checkup#TLSChecker)**
+**[godoc: TLSChecker](https://godoc.org/github.com/sourcegraph/checkup/check/tls)**
 
 ```js
 {
@@ -142,11 +155,11 @@ Here are the configuration structures you can use, which are explained fully [in
 
 #### Amazon S3 Storage
 
-**[godoc: S3](https://godoc.org/github.com/sourcegraph/checkup#S3)**
+**[godoc: S3](https://godoc.org/github.com/sourcegraph/checkup/check/s3)**
 
 ```js
 {
-	"provider": "s3",
+	"type": "s3",
 	"access_key_id": "<yours>",
 	"secret_access_key": "<yours>",
 	"bucket": "<yours>",
@@ -159,11 +172,11 @@ S3 is the default storage provider assumed by the status page, so the only chang
 
 #### File System Storage
 
-**[godoc: FS](https://godoc.org/github.com/sourcegraph/checkup#FS)**
+**[godoc: FS](https://godoc.org/github.com/sourcegraph/checkup/storage/fs)**
 
 ```js
 {
-	"provider": "fs",
+	"type": "fs",
 	"dir": "/path/to/your/check_files",
 	"url": "http://127.0.0.1:2015/check_files"
 }
@@ -180,11 +193,11 @@ Then fill out [config.js](https://github.com/sourcegraph/checkup/blob/master/sta
 
 #### GitHub Storage
 
-**[godoc: GitHub](https://godoc.org/github.com/sourcegraph/checkup#GitHub)**
+**[godoc: GitHub](https://godoc.org/github.com/sourcegraph/checkup/storage/github)**
 
 ```js
 {
-	"provider": "github",
+	"type": "github",
 	"access_token": "some_api_access_token_with_repo_scope",
 	"repository_owner": "owner",
 	"repository_name": "repo",
@@ -209,22 +222,22 @@ Where "dir" is a subdirectory within the repo to push all the check files. Setup
 
 #### SQL Storage (sqlite3/PostgreSQL)
 
-**[godoc: SQL](https://godoc.org/github.com/sourcegraph/checkup#SQL)**
+**[godoc: SQL](https://godoc.org/github.com/sourcegraph/checkup/storage/sql)**
 
 Postgres or sqlite3 databases can be used as storage backends.
 
 sqlite database file configuration:
 ```js
 {
-	"provider": "sql",
+	"type": "sql",
 	"sqlite_db_file": "/path/to/your/sqlite.db"
 }
 ```
 
 postgresql database file configuration:
 ```js
 {
-	"provider": "sql",
+	"type": "sql",
 	"postgresql": {
 		"user": "postgres",
 		"dbname": "dbname",
@@ -251,7 +264,7 @@ Currently the status page does not support SQL storage.
 Enable notifications in Slack with this Notifier configuration:
 ```js
 {
-	"name": "slack",
+	"type": "slack",
 	"username": "username",
 	"channel": "#channel-name",
 	"webhook": "webhook-url"
@@ -260,6 +273,26 @@ Enable notifications in Slack with this Notifier configuration:
 
 Follow these instructions to [create a webhook](https://get.slack.help/hc/en-us/articles/115005265063-Incoming-WebHooks-for-Slack).
 
+#### Mail notifier
+
+Enable E-mail notifications with this Notifier configuration:
+```js
+{
+	"type": "mail",
+	"from": "[email protected]",
+	"to": [ "[email protected]", "[email protected]" ],
+	"subject": "Custom subject line",
+	"smtp": {
+		"server": "smtp.example.com",
+		"port": 25,
+		"username": "username",
+		"password": "password"
+	}
+}
+```
+
+The settings for `subject`, `smtp.port` (default to 25), `smtp.username` and `smtp.password` are optional.
+
 ## Setting up storage on S3
 
 The easiest way to do this is to give an IAM user these two privileges (keep the credentials secret):
@@ -453,34 +486,18 @@ You can implement your own Checker and Storage types. If it's general enough, fe
 
 ### Building Locally
 
-Requires Go v1.10 or newer.
+Requires Go v1.13 or newer.
 
 ```bash
 git clone [email protected]:sourcegraph/checkup.git
-cd checkup/cmd/checkup/
-
-# Install dependencies
-go get -v -d
-
-# Build binary
-go build -v -ldflags '-s' -o ../../checkup
-
-# Run tests
-go test -race ../../
+cd checkup
+make
 ```
 
-### Building with Docker
+Building the SQL enabled version is done with `make build-sql`.
 
-Linux binary:
-
-```bash
-git clone [email protected]:sourcegraph/checkup.git
-cd checkup
-docker pull golang:latest
-docker run --net=host --rm \
--v `pwd`:/project \
--w /project golang bash \
--c "cd cmd/checkup; go get -v -d; go build -v -ldflags '-s' -o ../../checkup"
-```
+### Building a Docker image
 
-This will create a checkup binary in the root project folder.
+If you would like to run checkup in a docker container, building it is done by running `make docker`.
+It will build the version without sql support. An SQL supported docker image is currently not provided,
+but there's a plan to do that in the future.

check.go

@@ -0,0 +1,29 @@
+package checkup
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/sourcegraph/checkup/check/dns"
+	"github.com/sourcegraph/checkup/check/exec"
+	"github.com/sourcegraph/checkup/check/http"
+	"github.com/sourcegraph/checkup/check/tcp"
+	"github.com/sourcegraph/checkup/check/tls"
+)
+
+func checkerDecode(typeName string, config json.RawMessage) (Checker, error) {
+	switch typeName {
+	case dns.Type:
+		return dns.New(config)
+	case exec.Type:
+		return exec.New(config)
+	case http.Type:
+		return http.New(config)
+	case tcp.Type:
+		return tcp.New(config)
+	case tls.Type:
+		return tls.New(config)
+	default:
+		return nil, fmt.Errorf(errUnknownCheckerType, typeName)
+	}
+}

dnschecker.go → check/dns/dns.go

@@ -1,15 +1,21 @@
-package checkup
+package dns
 
 import (
+	"encoding/json"
 	"fmt"
 	"net"
 	"time"
 
 	"github.com/miekg/dns"
+
+	"github.com/sourcegraph/checkup/types"
 )
 
-// DNSChecker implements a Checker for TCP endpoints.
-type DNSChecker struct {
+// Type should match the package name
+const Type = "dns"
+
+// Checker implements a Checker for TCP endpoints.
+type Checker struct {
 	// Name is the name of the endpoint.
 	Name string `json:"endpoint_name"`
 	// This is the name of the DNS server you are testing.
@@ -31,29 +37,43 @@ type DNSChecker struct {
 	Attempts int `json:"attempts,omitempty"`
 }
 
+// New creates a new Checker instance based on json config
+func New(config json.RawMessage) (Checker, error) {
+	var checker Checker
+	err := json.Unmarshal(config, &checker)
+	return checker, err
+}
+
+// Type returns the checker package name
+func (Checker) Type() string {
+	return Type
+}
+
 // Check performs checks using c according to its configuration.
 // An error is only returned if there is a configuration error.
-func (c DNSChecker) Check() (Result, error) {
+func (c Checker) Check() (types.Result, error) {
 	if c.Attempts < 1 {
 		c.Attempts = 1
 	}
 
-	result := Result{Title: c.Name, Endpoint: c.URL, Timestamp: Timestamp()}
+	result := types.NewResult()
+	result.Title = c.Name
+	result.Endpoint = c.URL
 	result.Times = c.doChecks()
 
 	return c.conclude(result), nil
 }
 
 // doChecks executes and returns each attempt.
-func (c DNSChecker) doChecks() Attempts {
+func (c Checker) doChecks() types.Attempts {
 	var conn net.Conn
 
 	timeout := c.Timeout
 	if timeout == 0 {
 		timeout = 1 * time.Second
 	}
 
-	checks := make(Attempts, c.Attempts)
+	checks := make(types.Attempts, c.Attempts)
 	for i := 0; i < c.Attempts; i++ {
 		var err error
 		start := time.Now()
@@ -86,7 +106,7 @@ func (c DNSChecker) doChecks() Attempts {
 // computes remaining values needed to fill out the result.
 // It detects degraded (high-latency) responses and makes
 // the conclusion about the result's status.
-func (c DNSChecker) conclude(result Result) Result {
+func (c Checker) conclude(result types.Result) types.Result {
 	result.ThresholdRTT = c.ThresholdRTT
 
 	// Check errors (down)

dnschecker_test.go → check/dns/dns_test.go

@@ -1,12 +1,12 @@
-package checkup
+package dns
 
 import (
 	"net"
 	"testing"
 	"time"
 )
 
-func TestDNSChecker(t *testing.T) {
+func TestChecker(t *testing.T) {
 	// Listen on localhost, random port
 	srv, err := net.Listen("tcp", "localhost:8382")
 	if err != nil {
@@ -28,7 +28,7 @@ func TestDNSChecker(t *testing.T) {
 	// Should know the host:port by now
 	endpt := srv.Addr().String()
 	testName := "TestDNS"
-	hc := DNSChecker{Name: testName, URL: endpt, Attempts: 2}
+	hc := Checker{Name: testName, URL: endpt, Attempts: 2}
 
 	// Try an up server
 	result, err := hc.Check()
@@ -102,7 +102,7 @@ func TestDNSChecker(t *testing.T) {
 	}
 }
 
-func TestDNSCheckerWithAgressiveTimeout(t *testing.T) {
+func TestCheckerWithAgressiveTimeout(t *testing.T) {
 	// Listen on localhost, random port
 	srv, err := net.Listen("tcp", "localhost:0")
 	if err != nil {
@@ -124,7 +124,7 @@ func TestDNSCheckerWithAgressiveTimeout(t *testing.T) {
 	// Should know the host:port by now
 	endpt := srv.Addr().String()
 	testName := "TestTCP"
-	hc := DNSChecker{Name: testName, URL: endpt, Attempts: 2, Timeout: 1 * time.Nanosecond}
+	hc := Checker{Name: testName, URL: endpt, Attempts: 2, Timeout: 1 * time.Nanosecond}
 
 	result, err := hc.Check()
 	if err != nil {