fixes #104 by supporting properties via environment variables

.gitignore

@@ -1,7 +1,7 @@
 *.class
 *.iml
 *.jar
-/.calva/output-window/
+/.calva/repl.calva-repl
 /.clj-kondo/.cache/
 /.cpcache/
 /.idea/

README.md

@@ -40,7 +40,7 @@ clojure -M:clj-watson scan -p deps.edn
 The first time it runs, it will download the entire vulnerability database, which
 can take several minutes. Subsequent runs will be much faster.
 
-> [!NOTE] 
+> [!NOTE]
 > The database is stored in the `/tmp/db/` folder (on macOS/Linux) - in case you ever need to delete that folder, if it looks like the database is corrupted.
 
 `clj-watson` can also be installed as a Clojure CLI tool:
@@ -105,7 +105,8 @@ It is easy to [request an API key](https://github.com/jeremylong/DependencyCheck
 You can specify you key via:
 
 1. The `nvd.api.key` Java system property on the command line
-2. Or, an `nvd.api.key` entry in your `clj-watson.properties` file
+2. Or, the `CLJ_WATSON_NVD_API_KEY` environment variable
+3. Or, an `nvd.api.key` entry in your `clj-watson.properties` file
 
 > [!CAUTION]
 > Keeping your nvd api key secret is your responsibility.
@@ -129,7 +130,39 @@ clojure -J-Dnvd.api.key=<your key here> -Tclj-watson scan :p deps.edn
 Replace `<your key here>` with your actual api key.
 
 > [!CAUTION]
-> You could specify this system property under `:jvm-opts` in your `deps.edn` under your `:clj-watson` alias, but be careful not to commit it to version control. 
+> You could specify this system property under `:jvm-opts` in your `deps.edn` under your `:clj-watson` alias, but be careful not to commit it to version control.
+
+##### Via Environment Variable
+
+Example usage:
+
+```shell
+CLJ_WATSON_NVD_API_KEY=<your key here> clojure -M:clj-watson scan -p deps.edn
+```
+
+Or:
+
+```shell
+export CLJ_WATSON_NVD_API_KEY=<your key here>
+
+clojure -M:clj-watson scan -p deps.edn
+```
+
+Or:
+
+```shell
+CLJ_WATSON_NVD_API_KEY=<your key here> clojure -Tclj-watson scan :p deps.edn
+```
+
+Or:
+
+```shell
+export CLJ_WATSON_NVD_API_KEY=<your key here>
+
+clojure -Tclj-watson scan :p deps.edn
+```
+
+Replace `<your key here>` with your actual api key.
 
 ##### Via the `clj-watson.properties` File
 
@@ -154,7 +187,7 @@ Or:
 clojure -Tclj-watson scan :p deps.edn :clj-watson-properties ./clj-watson.properties
 ```
 
-> [!CAUTION] 
+> [!CAUTION]
 > Be careful not to commit your key to version control.
 
 ### GitHub Advisory Database [experimental]
@@ -233,7 +266,7 @@ the `--suggest-fix` or `-s` option when running `clj-watson`.
 # Installation
 
 > [!IMPORTANT]
-> You'll need to [setup your NVD API key](#nist-nvd-api). 
+> You'll need to [setup your NVD API key](#nist-nvd-api).
 
 `clj-watson` can be installed as a Clojure CLI tool, as shown above. While
 this is the easiest way to install the latest version and keep it up-to-date
@@ -309,6 +342,8 @@ OPTIONS valid when database-strategy is dependency-check:
                                                              See docs for configuration. [false]
 ```
 
+## Properties
+
 By default, when using the DEPENDENCY-CHECK strategy, `clj-watson` will load
 its own `dependency-check.properties` file, and then look for a
 `clj-watson.properties` file on the classpath and load that if found, for
@@ -324,14 +359,35 @@ that file and apply those properties to the dependency-check scan. This is
 in addition to the properties loaded from the `dependency-check.properties`
 or the `-d` file. This can be useful to override just a few properties.
 
+In addition, relevant properties provided as Java system properties are
+read by the underlying DependencyCheck scan, and take precedence over the
+properties provided in these files. See the `-Dnvd.api.key=` example above.
+
+## Environment Variables
+
+`clj-watson` also supports environment variables that start with `CLJ_WATSON_`.
+These are used to set properties that are not provided on the command line.
+The `CLJ_WATSON_` prefix is removed, and the rest of the name is converted to
+a lowercase property name with `_` replaced by `.` (e.g., `CLJ_WATSON_NVD_API_KEY`).
+To specify a property name that contains an underscore, use two underscores
+in the environment variable name, e.g., `CLJ_WATSON_DATA_FILE__NAME` to
+set the `data.file_name` property.
+
+Properties set via environment variables take precedence over those set in
+the properties files described above, but not over Java system properties
+set on the command-line.
+
+Environment variables are often the most straightforward and most secure
+way to provide sensitive information like API keys in various CI systems.
+
 # Execution
 
 The minimum needed to run `clj-watson` is to provide the path to a `deps.edn`
 file, but it is recommended that you also provide the `-s` option so
 `clj-watson` will try to suggest remediations for any vulnerabilities found.
 
 > [!IMPORTANT]
-> You'll need to first [setup your NVD API key](#nist-nvd-api). 
+> You'll need to first [setup your NVD API key](#nist-nvd-api).
 
 ```bash
 clojure -M:clj-watson -p deps.edn
@@ -383,6 +439,7 @@ It writes settings and vulnerability findings to `stdout`.
 # Who uses it
 
 - [180 Seguros](https://180s.com.br)
+- [org.clojure/tools.deps](https://github.com/clojure/tools.deps)
 - [World Singles Networks](https://worldsinglesnetworks.com/)
 
 # Development

src/clj_watson/controller/dependency_check/scanner.clj

@@ -21,16 +21,40 @@
   ;; ensure (fake) API key is redacted:
   (sanitize-property "nvd.api.key=72a48765-90ab-5678-abcd-1234abcd5489"))
 
+(defn ^:private env-var->property [env-var]
+  (-> env-var
+      (string/replace #"^CLJ_WATSON_" "") ; strip prefix
+      (string/lower-case)                 ; lowercase
+      (string/replace "_" ".")            ; _ -> .
+      (string/replace ".." "_")))         ; allow __ -> .. -> _
+
+(comment
+  (env-var->property "CLJ_WATSON_NVD_API_KEY")
+  (env-var->property "CLJ_WATSON_DATA_FILE__NAME"))
+
+(defn ^:private set-watson-env-vars-as-properties []
+  (run! (fn [[env-var value]]
+          (when (string/starts-with? env-var "CLJ_WATSON_")
+            (let [property (env-var->property env-var)
+                  p-value  (System/getProperty property)]
+              (if p-value
+                (println (str "Ignoring " env-var " as " property " is already set."))
+                (do
+                  (println (str "Setting " property " from " env-var "."))
+                  (System/setProperty property value))))))
+        (System/getenv))
+  (println))
+
 (defn ^:private create-settings [^String properties-file-path ^String additional-properties-file-path]
-  (let [settings (Settings.)]
-    (let [props
-          (if properties-file-path
-            (->> properties-file-path File.)
-            (->> "dependency-check.properties" io/resource))]
-      (println (str "\nRead " (count (line-seq (io/reader props))) " dependency-check properties."))
-      (if properties-file-path
-        (->> props (.mergeProperties settings))
-        (->> props slurp .getBytes ByteArrayInputStream. (.mergeProperties settings))))
+  (let [settings (Settings.)
+        props
+        (if properties-file-path
+          (->> properties-file-path File.)
+          (->> "dependency-check.properties" io/resource))]
+    (println (str "\nRead " (count (line-seq (io/reader props))) " dependency-check properties."))
+    (if properties-file-path
+      (->> props (.mergeProperties settings))
+      (->> props slurp .getBytes ByteArrayInputStream. (.mergeProperties settings)))
     (if-let [add-props
              (if additional-properties-file-path
                (->> additional-properties-file-path File.)
@@ -50,6 +74,7 @@
           (->> add-props (.mergeProperties settings))
           (some->> add-props slurp .getBytes ByteArrayInputStream. (.mergeProperties settings))))
       (println "No additional properties found.\n"))
+    (set-watson-env-vars-as-properties)
     settings))
 
 (defn ^:private validate-settings