Add configuration via environment

NEWS.md

@@ -6,15 +6,16 @@
 ### New Features
 
 * Support for HTTPS
-* Provide the `groupby` query parameter, and ability to aggregate query features
-* Support OGC API `sortby` query parameter (`orderBy` is deprecated)
 * Support Postgres data types: JSON, array of text/int/float/numeric
 * Add support for partitioned tables and foreign tables
 * Add configuration to include/exclude published schemas and tables
 * Add configuration for web UI map view basemap URL template
 * Add configuration to set base path (#88)
-* Add standard query parameters `crs` and `bbox-crs` (#98)
+* Add configuration via enviroment variables (#104)
 * Allow configuring published function schemas (#99)
+* Add the `groupby` query parameter, and ability to aggregate query features
+* Support OGC API query parameter `sortby` (`orderBy` is deprecated)
+* Add OGC API query parameters `crs` and `bbox-crs` (#98)
 * Add support for CQL filtering with `filter` and `filter-crs` query parameters (#101, #102, #103)
 
 ### Performance Improvements

README.md

@@ -13,7 +13,7 @@ It supports the [*OGC API - Features*](https://ogcapi.ogc.org/features/) REST AP
 
 * Implements the [*OGC API - Features*](https://ogcapi.ogc.org/features/) standard.
   * Standard query parameters: `limit`, `bbox`, `bbox-crs`, property filtering, `sortby`, `crs`
-  * Query parameters `filter` and `filter-crs` allow [CQL filtering](https://portal.ogc.org/files/96288), with spatial support 
+  * Query parameters `filter` and `filter-crs` allow [CQL filtering](https://portal.ogc.org/files/96288), with spatial support
   * Extended query parameters: `offset`, `properties`, `transform`, `precision`, `groupby`
 * Data responses are formatted in JSON and [GeoJSON](https://www.rfc-editor.org/rfc/rfc7946.txt)
 * Provides a simple HTML user interface, with web maps to view spatial data
@@ -22,7 +22,7 @@ It supports the [*OGC API - Features*](https://ogcapi.ogc.org/features/) REST AP
   * Feature collections are defined by database objects (tables and views)
   * Filters are executed in the database, and use indexes where defined
 * Uses PostGIS to provide geospatial functionality:
-  * Spatial filtering  
+  * Spatial filtering
   * Transforming geometry data into the output coordinate system
   * Marshalling feature data into GeoJSON
 * Full-featured HTTP support
@@ -56,7 +56,7 @@ Builds of the latest code:
 * [Docker](https://hub.docker.com/r/pramsey/pg_featureserv)
 
 
-## Building from Source
+## Build from Source
 
 `pg_featureserv` is developed under Go 1.13.  It may also work with earlier versions.
 
@@ -70,7 +70,7 @@ go build
 * This creates a `pg_featureserv` executable in the application directory
 * (Optional) Run the unit tests using `go test ./...`
 
-### Building a Docker image
+### Build a Docker image
 
 * Build the `pg_featureserv` executable with the command:
 ```bash
@@ -84,14 +84,42 @@ docker build -f container/Dockerfile --build-arg VERSION=<VERSION> -t crunchydat
 ```
 Replace version `<VERSION>` with the `pg_featureserv` version you are building against.
 
-## Configuring the service
+## Configure the service
 
-* Set the environment variable `DATABASE_URL` with a Postgres [connection string](https://www.postgresql.org/docs/12/libpq-connect.html#LIBPQ-CONNSTRING)
-  * Example: `export DATABASE_URL="host=localhost user=postgres"`
-  * Database URL can also be set in the configuration file
-* Edit the configuration file `pg_featureserv.toml`, located in `./config`, `/config`, or `/etc`
+The [configuration file](config/pg_featureserv.toml.example) is automatically read from the following locations, if it exists:
 
-## Running the service
+* In the system configuration directory, at `/etc/pg_featureserv.toml`
+* Relative to the directory from which the program is run, `./config/pg_featureserv.toml`
+* In a root volume at `/config/pg_featureserv.toml`
+
+To specify a configuration file directly use the `--config` commandline parameter.
+In this case configuration files in other locations are ignored.
+
+### Configuration Using Environment Variables
+
+To set the database connection the environment variable `DATABASE_URL`
+can be used with a
+Postgres [connection string](https://www.postgresql.org/docs/12/libpq-connect.html#LIBPQ-CONNSTRING):
+```bash
+export DATABASE_URL="host=localhost user=postgres"
+```
+
+Other parameters in the configuration file can be over-ridden at run-time in the environment.
+Prepend the upper-cased parameter name with `PGFS_section_` to set the value.
+For example, to change the HTTP port and service title:
+```bash
+export PGFS_SERVER_HTTPPORT=8889
+export PGFS_METADATA_TITLE="My PGFS"
+```
+
+### SSL
+For SSL support, you will need both a server private key and an authority certificate.
+For testing purposes you can generate a self-signed key/cert pair using `openssl`:
+```bash
+openssl req  -nodes -new -x509  -keyout server.key -out server.crt
+```
+
+## Run the service
 
 * If not already done, move to the application directory:
   * `cd $GOPATH/src/github.com/CrunchyData/pg_featureserv`
@@ -109,6 +137,19 @@ Replace version `<VERSION>` with the `pg_featureserv` version you are building a
 * `--test` - run in test mode, with an internal catalog of tables and data
 * `--version` - display the version number
 
+## Troubleshooting
+
+To get information about what is going on behind the scenes,
+run with the `--debug` commandline parameter.
+```sh
+./pg_featureserv --debug
+```
+Debugging can also be enabled via the configuration file (`Server.Debug=true`),
+or in the environment:
+```sh
+export PGFS_SERVER_DEBUG=true
+ ```
+
 ## Requests Overview
 
 Features are identified by a _collection name_ and _feature id_ pair.

internal/conf/appconfig.go

@@ -20,12 +20,14 @@ type AppConfiguration struct {
 	// AppName name of the software
 	Name string
 	// AppVersion version number of the software
-	Version  string
-	EnvDBURL string
+	Version   string
+	EnvDBURL  string
+	EnvPrefix string
 }
 
 var AppConfig = AppConfiguration{
-	Name:     "pg_featureserv",
-	Version:  setVersion,
-	EnvDBURL: "DATABASE_URL",
+	Name:      "pg_featureserv",
+	Version:   setVersion,
+	EnvDBURL:  "DATABASE_URL",
+	EnvPrefix: "PGFS",
 }

internal/conf/config.go

@@ -94,7 +94,7 @@ type Database struct {
 
 // Metadata config
 type Metadata struct {
-	Title       string
+	Title       string //`mapstructure:"METADATA_TITLE"`
 	Description string
 }
 
@@ -108,10 +108,18 @@ func (conf *Config) IsTLSEnabled() bool {
 }
 
 // InitConfig initializes the configuration from the config file
-func InitConfig(configFilename string) {
+func InitConfig(configFilename string, isDebug bool) {
 	// --- defaults
 	setDefaultConfig()
 
+	if isDebug {
+		viper.Set("Debug", true)
+	}
+
+	viper.SetEnvPrefix(AppConfig.EnvPrefix)
+	viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
+	viper.AutomaticEnv()
+
 	isExplictConfigFile := configFilename != ""
 	confFile := AppConfig.Name + ".toml"
 	if configFilename != "" {

pg_featureserv.go

@@ -75,7 +75,7 @@ func main() {
 
 	log.Infof("----  %s - Version %s ----------\n", conf.AppConfig.Name, conf.AppConfig.Version)
 
-	conf.InitConfig(flagConfigFilename)
+	conf.InitConfig(flagConfigFilename, flagDebugOn)
 
 	var catalog data.Catalog
 	if flagTestModeOn {