Adds optional depth parameter for specifying the number of git commits

README.md

@@ -72,6 +72,14 @@ filed named `.gitkeep`. Finally, create individual locks by making an empty file
   retrying to acquire a lock or release a lock. The default is 10 seconds.
   Valid values: `60s`, `90m`, `1h`.
 
+### Example
+
+Fetching a repo with only 100 commits of history:
+
+``` yaml
+- get: source-code
+  params: {depth: 100}
+```
 
 ## Behavior
 
@@ -83,13 +91,18 @@ given, the ref for `HEAD` is returned.
 
 ### `in`: Fetch an acquired lock.
 
+
 Outputs 2 files:
 
 * `metadata`: Contains the contents of whatever was in your lock file. This is
   useful for environment configuration settings.
 
 * `name`: Contains the name of lock that was acquired.
 
+#### Parameters
+
+* `depth`: *Optional.* If a positive integer is given, *shallow* clone the
+  repository using the `--depth` option.
 
 ### `out`: Acquire, release, add, or remove a lock.
 

assets/in

@@ -39,6 +39,7 @@ uri=$(jq -r '.source.uri // ""' < $payload)
 branch=$(jq -r '.source.branch // ""' < $payload)
 pool_name=$(jq -r '.source.pool // ""' < $payload)
 ref=$(jq -r '.version.ref // "HEAD"' < $payload)
+depth=$(jq -r '(.params.depth // 0)' < $payload)
 
 if [ -z "$uri" ]; then
   config_errors="${config_errors}invalid payload (missing uri)\n"
@@ -62,7 +63,12 @@ if [ -n "$branch" ]; then
   branchflag="--branch $branch"
 fi
 
-git clone --single-branch $uri $branchflag $destination
+depthflag=""
+if test "$depth" -gt 0 2> /dev/null; then
+  depthflag="--depth $depth"
+fi
+
+git clone --single-branch $depthflag $uri $branchflag $destination
 
 cd $destination