From bd2017314fbe1b43aa2c80fbee708cf5e3e5e4ae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Mierzwa?= <l.mierzwa@gmail.com>
Date: Wed, 26 Feb 2020 10:27:49 +0000
Subject: [PATCH] fix(backend): correctly load configuration using CONFIG_FILE
 env variable

Fixes #1466
---
 .../testscript/config_file_flag_over_env.txt  | 28 +++++++++++++++++++
 .../tests/testscript/config_file_from_env.txt | 15 ++++++++++
 .../testscript/config_file_from_flag.txt      | 15 ++++++++++
 cmd/karma/tests/testscript/invalid_flag.txt   |  6 ++++
 internal/config/config.go                     | 14 ++++++++--
 5 files changed, 75 insertions(+), 3 deletions(-)
 create mode 100644 cmd/karma/tests/testscript/config_file_flag_over_env.txt
 create mode 100644 cmd/karma/tests/testscript/config_file_from_env.txt
 create mode 100644 cmd/karma/tests/testscript/config_file_from_flag.txt
 create mode 100644 cmd/karma/tests/testscript/invalid_flag.txt

diff --git a/cmd/karma/tests/testscript/config_file_flag_over_env.txt b/cmd/karma/tests/testscript/config_file_flag_over_env.txt
new file mode 100644
index 000000000..253ba6d15
--- /dev/null
+++ b/cmd/karma/tests/testscript/config_file_flag_over_env.txt
@@ -0,0 +1,28 @@
+# Loads config file from flags when CONFIG_FILE env is also set
+env CONFIG_FILE=env.yaml
+karma.bin-should-work --check-config --config.file=flag.yaml
+! stdout .
+stderr 'msg="Reading configuration file flag.yaml"'
+stderr 'msg="Configuration is valid"'
+stderr 'msg="\[flag\] Configured Alertmanager source at http://localhost:8080 \(proxied: false\, readonly: false\)"'
+! stderr 'level=error'
+! stderr 'msg="Reading configuration file karma.yaml"'
+! stderr 'msg="Reading configuration file env.yaml"'
+
+-- flag.yaml --
+alertmanager:
+  servers:
+    - name: flag
+      uri: "http://localhost:8080"
+
+-- env.yaml --
+alertmanager:
+  servers:
+    - name: env
+      uri: "http://localhost:8080"
+
+-- karma.yaml --
+alertmanager:
+  servers:
+    - name: karma
+      uri: "http://localhost:8080"
diff --git a/cmd/karma/tests/testscript/config_file_from_env.txt b/cmd/karma/tests/testscript/config_file_from_env.txt
new file mode 100644
index 000000000..f5ed35286
--- /dev/null
+++ b/cmd/karma/tests/testscript/config_file_from_env.txt
@@ -0,0 +1,15 @@
+# Loads config file from CONFIG_FILE env
+env CONFIG_FILE=foo.yaml
+karma.bin-should-work --check-config
+! stdout .
+stderr 'msg="Reading configuration file foo.yaml"'
+stderr 'msg="Configuration is valid"'
+stderr 'msg="\[cwd\] Configured Alertmanager source at http://localhost:8080 \(proxied: true\, readonly: false\)"'
+! stderr 'level=error'
+
+-- foo.yaml --
+alertmanager:
+  servers:
+    - name: cwd
+      uri: "http://localhost:8080"
+      proxy: true
diff --git a/cmd/karma/tests/testscript/config_file_from_flag.txt b/cmd/karma/tests/testscript/config_file_from_flag.txt
new file mode 100644
index 000000000..906266cc5
--- /dev/null
+++ b/cmd/karma/tests/testscript/config_file_from_flag.txt
@@ -0,0 +1,15 @@
+# Loads config file from --config.file flag
+env CONFIG_FILE=foo.yaml
+karma.bin-should-work --check-config --config.file foo.yaml
+! stdout .
+stderr 'msg="Reading configuration file foo.yaml"'
+stderr 'msg="Configuration is valid"'
+stderr 'msg="\[cwd\] Configured Alertmanager source at http://localhost:8080 \(proxied: true\, readonly: false\)"'
+! stderr 'level=error'
+
+-- foo.yaml --
+alertmanager:
+  servers:
+    - name: cwd
+      uri: "http://localhost:8080"
+      proxy: true
diff --git a/cmd/karma/tests/testscript/invalid_flag.txt b/cmd/karma/tests/testscript/invalid_flag.txt
new file mode 100644
index 000000000..16d720cfe
--- /dev/null
+++ b/cmd/karma/tests/testscript/invalid_flag.txt
@@ -0,0 +1,6 @@
+# Fails on invalid flag usage
+env CONFIG_FILE=foo.yaml
+karma.bin-should-fail --check-config --invalid.flag
+! stdout .
+! stderr 'msg="Configuration is valid"'
+stderr 'level=error msg="unknown flag: --invalid.flag"'
diff --git a/internal/config/config.go b/internal/config/config.go
index 6dda2fb42..bf21b7c2b 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -121,9 +121,17 @@ func SetupFlags(f *pflag.FlagSet) {
 }
 
 func readConfigFile(k *koanf.Koanf, flags *pflag.FlagSet) string {
-	configFile, _ := flags.GetString("config.file")
-	// if config.file is not passed via flags then see if there's karma.yaml in
-	// current working directory
+	var configFile string
+
+	// 1. Load file from flags is set
+	configFile, _ = flags.GetString("config.file")
+	// 2. Fallback to CONFIG_FILE env if there's no flag value
+	if configFile == "" {
+		if v, found := os.LookupEnv("CONFIG_FILE"); found {
+			configFile = v
+		}
+	}
+	// 3 see if there's karma.yaml in current working directory
 	if configFile == "" {
 		if _, err := os.Stat("karma.yaml"); !os.IsNotExist(err) {
 			configFile = "karma.yaml"