move loki client into separate package

internals/overlord/logstate/gatherer.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/canonical/pebble/internals/overlord/logstate/loki"
 	"gopkg.in/tomb.v2"
 
 	"github.com/canonical/pebble/internals/logger"
@@ -312,7 +313,7 @@ type logClient interface {
 func newLogClient(target *plan.LogTarget) (logClient, error) {
 	switch target.Type {
 	case plan.LokiTarget:
-		return newLokiClient(target), nil
+		return loki.NewClient(target), nil
 	//case plan.SyslogTarget: TODO
 	default:
 		return nil, fmt.Errorf("unknown type %q for log target %q", target.Type, target.Name)

internals/overlord/logstate/loki.go → internals/overlord/logstate/loki/loki.go

@@ -12,7 +12,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package logstate
+package loki
 
 import (
 	"bytes"
@@ -31,11 +31,11 @@ import (
 )
 
 const (
-	maxLokiRequestSize = 10
-	lokiRequestTimeout = 10 * time.Second
+	maxRequestSize = 10
+	requestTimeout = 10 * time.Second
 )
 
-type lokiClient struct {
+type Client struct {
 	target    *plan.LogTarget
 	remoteURL string
 	// buffered entries are "sharded" by service name
@@ -45,32 +45,32 @@ type lokiClient struct {
 	httpClient http.Client
 }
 
-func newLokiClient(target *plan.LogTarget) logClient {
-	return &lokiClient{
+func NewClient(target *plan.LogTarget) *Client {
+	return &Client{
 		target:     target,
 		remoteURL:  target.Location,
 		entries:    map[string][]lokiEntry{},
-		httpClient: http.Client{Timeout: lokiRequestTimeout},
+		httpClient: http.Client{Timeout: requestTimeout},
 	}
 }
 
-func (c *lokiClient) Write(ctx context.Context, entry servicelog.Entry) error {
-	c.entries[entry.Service] = append(c.entries[entry.Service], asLokiEntry(entry))
+func (c *Client) Write(ctx context.Context, entry servicelog.Entry) error {
+	c.entries[entry.Service] = append(c.entries[entry.Service], encodeEntry(entry))
 	c.numEntries++
-	if c.numEntries >= maxLokiRequestSize {
+	if c.numEntries >= maxRequestSize {
 		return c.Flush(ctx)
 	}
 	return nil
 }
 
-func asLokiEntry(entry servicelog.Entry) lokiEntry {
+func encodeEntry(entry servicelog.Entry) lokiEntry {
 	return lokiEntry{
 		strconv.FormatInt(entry.Time.UnixNano(), 10),
 		strings.TrimSuffix(entry.Message, "\n"),
 	}
 }
 
-func (c *lokiClient) Flush(ctx context.Context) error {
+func (c *Client) Flush(ctx context.Context) error {
 	if c.numEntries == 0 {
 		return nil // no-op
 	}
@@ -113,7 +113,7 @@ func (c *lokiClient) Flush(ctx context.Context) error {
 	return nil
 }
 
-func (c *lokiClient) buildRequest() lokiRequest {
+func (c *Client) buildRequest() request {
 	// Sort keys to guarantee deterministic output
 	var services []string
 	for svc, entries := range c.entries {
@@ -124,10 +124,10 @@ func (c *lokiClient) buildRequest() lokiRequest {
 	}
 	sort.Strings(services)
 
-	var req lokiRequest
+	var req request
 	for _, service := range services {
 		entries := c.entries[service]
-		stream := lokiStream{
+		stream := stream{
 			Labels: map[string]string{
 				"pebble_service": service,
 			},
@@ -138,18 +138,18 @@ func (c *lokiClient) buildRequest() lokiRequest {
 	return req
 }
 
-func (c *lokiClient) emptyBuffer() {
+func (c *Client) emptyBuffer() {
 	for svc := range c.entries {
 		c.entries[svc] = c.entries[svc][:0]
 	}
 	c.numEntries = 0
 }
 
-type lokiRequest struct {
-	Streams []lokiStream `json:"streams"`
+type request struct {
+	Streams []stream `json:"streams"`
 }
 
-type lokiStream struct {
+type stream struct {
 	Labels  map[string]string `json:"stream"`
 	Entries []lokiEntry       `json:"values"`
 }

internals/overlord/logstate/loki_test.go → internals/overlord/logstate/loki/loki_test.go

@@ -1,4 +1,4 @@
-package logstate
+package loki
 
 import (
 	"context"
@@ -113,7 +113,7 @@ func (*lokiSuite) TestLokiRequest(c *C) {
 	}))
 	defer server.Close()
 
-	client := newLokiClient(&plan.LogTarget{Location: server.URL})
+	client := NewClient(&plan.LogTarget{Location: server.URL})
 	for _, entry := range input {
 		err := client.Write(context.Background(), entry)
 		c.Assert(err, IsNil)
@@ -135,7 +135,7 @@ func (*lokiSuite) TestLokiFlushCancelContext(c *C) {
 	defer server.Close()
 	defer killServer()
 
-	client := newLokiClient(&plan.LogTarget{Location: server.URL})
+	client := NewClient(&plan.LogTarget{Location: server.URL})
 	err := client.Write(context.Background(), servicelog.Entry{
 		Time:    time.Now(),
 		Service: "svc1",