Use an enviroENV for db host

.project

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>clair</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+	</buildSpec>
+	<natures>
+	</natures>
+</projectDescription>

Dockerfile

@@ -14,12 +14,16 @@
 
 FROM golang:1.8-alpine
 
+ENV POSTGRESQL_SERVICE_HOST localhost
+
 VOLUME /config
 EXPOSE 6060 6061
 
 ADD .   /go/src/github.com/coreos/clair/
 WORKDIR /go/src/github.com/coreos/clair/
 
+COPY /config.yaml /etc/clair/config.yaml
+
 RUN apk add --no-cache git bzr rpm xz && \
     go install -v github.com/coreos/clair/cmd/clair && \
     mv /go/bin/clair /clair && \

config.yaml.sample

@@ -20,7 +20,7 @@ clair:
     options:
       # PostgreSQL Connection string
       # https://www.postgresql.org/docs/current/static/libpq-connect.html#LIBPQ-CONNSTRING
-      source: host=localhost port=5432 user=postgres sslmode=disable statement_timeout=60000
+      source: host=$POSTGRESQL_SERVICE_HOST port=5432 user=postgres sslmode=disable statement_timeout=60000
 
       # Number of elements kept in the cache
       # Values unlikely to change (e.g. namespaces) are cached in order to save prevent needless roundtrips to the database.

database/pgsql/pgsql.go

@@ -22,6 +22,7 @@ import (
 	"net/url"
 	"strings"
 	"time"
+	"os"
 
 	"gopkg.in/yaml.v2"
 
@@ -202,7 +203,12 @@ func openDatabase(registrableComponentConfig database.RegistrableComponentConfig
 	}
 
 	// Open database.
-	pg.DB, err = sql.Open("postgres", pg.config.Source)
+	host := os.Getenv("POSTGRESQL_SERVICE_HOST")
+	
+	modifiedSource := strings.Replace(pg.config.Source, "$POSTGRESQL_SERVICE_HOST", host, -1)
+	fmt.Println("postgresql hostname replaced: ", modifiedSource)
+	
+	pg.DB, err = sql.Open("postgres", modifiedSource)
 	if err != nil {
 		pg.Close()
 		return nil, fmt.Errorf("pgsql: could not open database: %v", err)